< draft-ietf-ipsecme-iptfs-06.txt   draft-ietf-ipsecme-iptfs-07.txt >
Network Working Group C. Hopps Network Working Group C. Hopps
Internet-Draft LabN Consulting, L.L.C. Internet-Draft LabN Consulting, L.L.C.
Intended status: Standards Track January 19, 2021 Intended status: Standards Track February 22, 2021
Expires: July 23, 2021 Expires: August 26, 2021
IP-TFS: IP Traffic Flow Security Using Aggregation and Fragmentation IP-TFS: IP Traffic Flow Security Using Aggregation and Fragmentation
draft-ietf-ipsecme-iptfs-06 draft-ietf-ipsecme-iptfs-07
Abstract Abstract
This document describes a mechanism to enhance IPsec traffic flow This document describes a mechanism to enhance IPsec traffic flow
security by adding traffic flow confidentiality to encrypted IP security (IP-TFS) by adding Traffic Flow Confidentiality (TFC) to
encapsulated traffic. Traffic flow confidentiality is provided by encrypted IP encapsulated traffic. TFC is provided by obscuring the
obscuring the size and frequency of IP traffic using a fixed-sized, size and frequency of IP traffic using a fixed-sized, constant-send-
constant-send-rate IPsec tunnel. The solution allows for congestion rate IPsec tunnel. The solution allows for congestion control as
control as well as non-constant send-rate usage. well as non-constant send-rate usage. The mechanisms defined in this
document are generic with the intent of allowing for non-TFS uses,
but such uses are outside the scope of this document.
Status of This Memo Status of This Memo
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provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on July 23, 2021. This Internet-Draft will expire on August 26, 2021.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology & Concepts . . . . . . . . . . . . . . . . . 3 1.1. Terminology & Concepts . . . . . . . . . . . . . . . . . 4
2. The IP-TFS Tunnel . . . . . . . . . . . . . . . . . . . . . . 4 2. The IP-TFS Tunnel . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Tunnel Content . . . . . . . . . . . . . . . . . . . . . 4 2.1. Tunnel Content . . . . . . . . . . . . . . . . . . . . . 4
2.2. Payload Content . . . . . . . . . . . . . . . . . . . . . 5 2.2. Payload Content . . . . . . . . . . . . . . . . . . . . . 5
2.2.1. Data Blocks . . . . . . . . . . . . . . . . . . . . . 6 2.2.1. Data Blocks . . . . . . . . . . . . . . . . . . . . . 6
2.2.2. No Implicit End Padding Required . . . . . . . . . . 6 2.2.2. End Padding . . . . . . . . . . . . . . . . . . . . . 6
2.2.3. Fragmentation, Sequence Numbers and All-Pad Payloads 6 2.2.3. Fragmentation, Sequence Numbers and All-Pad Payloads 6
2.2.4. Empty Payload . . . . . . . . . . . . . . . . . . . . 8 2.2.4. Empty Payload . . . . . . . . . . . . . . . . . . . . 8
2.2.5. IP Header Value Mapping . . . . . . . . . . . . . . . 8 2.2.5. IP Header Value Mapping . . . . . . . . . . . . . . . 8
2.2.6. IP Time-To-Live (TTL) and Tunnel errors . . . . . . . 9 2.2.6. IP Time-To-Live (TTL) and Tunnel errors . . . . . . . 9
2.2.7. Effective MTU of the Tunnel . . . . . . . . . . . . . 9 2.2.7. Effective MTU of the Tunnel . . . . . . . . . . . . . 9
2.3. Exclusive SA Use . . . . . . . . . . . . . . . . . . . . 9 2.3. Exclusive SA Use . . . . . . . . . . . . . . . . . . . . 9
2.4. Modes of Operation . . . . . . . . . . . . . . . . . . . 9 2.4. Modes of Operation . . . . . . . . . . . . . . . . . . . 10
2.4.1. Non-Congestion Controlled Mode . . . . . . . . . . . 9 2.4.1. Non-Congestion Controlled Mode . . . . . . . . . . . 10
2.4.2. Congestion Controlled Mode . . . . . . . . . . . . . 10 2.4.2. Congestion Controlled Mode . . . . . . . . . . . . . 10
3. Congestion Information . . . . . . . . . . . . . . . . . . . 11 2.5. Summary of Receiver Processing . . . . . . . . . . . . . 12
3.1. ECN Support . . . . . . . . . . . . . . . . . . . . . . . 12 3. Congestion Information . . . . . . . . . . . . . . . . . . . 12
4. Configuration . . . . . . . . . . . . . . . . . . . . . . . . 13 3.1. ECN Support . . . . . . . . . . . . . . . . . . . . . . . 13
4.1. Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . 13 4. Configuration . . . . . . . . . . . . . . . . . . . . . . . . 14
4.2. Fixed Packet Size . . . . . . . . . . . . . . . . . . . . 13 4.1. Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . 14
4.3. Congestion Control . . . . . . . . . . . . . . . . . . . 13 4.2. Fixed Packet Size . . . . . . . . . . . . . . . . . . . . 14
5. IKEv2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 4.3. Congestion Control . . . . . . . . . . . . . . . . . . . 14
5.1. USE_AGGFRAG Notification Message . . . . . . . . . . . . 13 5. IKEv2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6. Packet and Data Formats . . . . . . . . . . . . . . . . . . . 14 5.1. USE_AGGFRAG Notification Message . . . . . . . . . . . . 14
6.1. AGGFRAG_PAYLOAD Payload . . . . . . . . . . . . . . . . . 14 6. Packet and Data Formats . . . . . . . . . . . . . . . . . . . 15
6.1.1. Non-Congestion Control AGGFRAG_PAYLOAD Payload Format 15 6.1. AGGFRAG_PAYLOAD Payload . . . . . . . . . . . . . . . . . 15
6.1.2. Congestion Control AGGFRAG_PAYLOAD Payload Format . . 15 6.1.1. Non-Congestion Control AGGFRAG_PAYLOAD Payload Format 16
6.1.3. Data Blocks . . . . . . . . . . . . . . . . . . . . . 17 6.1.2. Congestion Control AGGFRAG_PAYLOAD Payload Format . . 16
6.1.4. IKEv2 USE_AGGFRAG Notification Message . . . . . . . 19 6.1.3. Data Blocks . . . . . . . . . . . . . . . . . . . . . 18
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20 6.1.4. IKEv2 USE_AGGFRAG Notification Message . . . . . . . 20
7.1. AGGFRAG_PAYLOAD Sub-Type Registry . . . . . . . . . . . . 20 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
7.2. USE_AGGFRAG Notify Message Status Type . . . . . . . . . 20 7.1. AGGFRAG_PAYLOAD Sub-Type Registry . . . . . . . . . . . . 21
8. Security Considerations . . . . . . . . . . . . . . . . . . . 20 7.2. USE_AGGFRAG Notify Message Status Type . . . . . . . . . 21
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 21 8. Security Considerations . . . . . . . . . . . . . . . . . . . 21
9.1. Normative References . . . . . . . . . . . . . . . . . . 21 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 22
9.2. Informative References . . . . . . . . . . . . . . . . . 21 9.1. Normative References . . . . . . . . . . . . . . . . . . 22
Appendix A. Example Of An Encapsulated IP Packet Flow . . . . . 23 9.2. Informative References . . . . . . . . . . . . . . . . . 22
Appendix B. A Send and Loss Event Rate Calculation . . . . . . . 24 Appendix A. Example Of An Encapsulated IP Packet Flow . . . . . 24
Appendix C. Comparisons of IP-TFS . . . . . . . . . . . . . . . 24 Appendix B. A Send and Loss Event Rate Calculation . . . . . . . 25
C.1. Comparing Overhead . . . . . . . . . . . . . . . . . . . 24 Appendix C. Comparisons of IP-TFS . . . . . . . . . . . . . . . 25
C.1.1. IP-TFS Overhead . . . . . . . . . . . . . . . . . . . 24 C.1. Comparing Overhead . . . . . . . . . . . . . . . . . . . 25
C.1.2. ESP with Padding Overhead . . . . . . . . . . . . . . 25 C.1.1. IP-TFS Overhead . . . . . . . . . . . . . . . . . . . 26
C.1.2. ESP with Padding Overhead . . . . . . . . . . . . . . 26
C.2. Overhead Comparison . . . . . . . . . . . . . . . . . . . 26 C.2. Overhead Comparison . . . . . . . . . . . . . . . . . . . 27
C.3. Comparing Available Bandwidth . . . . . . . . . . . . . . 26 C.3. Comparing Available Bandwidth . . . . . . . . . . . . . . 28
C.3.1. Ethernet . . . . . . . . . . . . . . . . . . . . . . 27 C.3.1. Ethernet . . . . . . . . . . . . . . . . . . . . . . 28
Appendix D. Acknowledgements . . . . . . . . . . . . . . . . . . 29 Appendix D. Acknowledgements . . . . . . . . . . . . . . . . . . 30
Appendix E. Contributors . . . . . . . . . . . . . . . . . . . . 29 Appendix E. Contributors . . . . . . . . . . . . . . . . . . . . 30
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 29 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 30
1. Introduction 1. Introduction
Traffic Analysis ([RFC4301], [AppCrypt]) is the act of extracting Traffic Analysis ([RFC4301], [AppCrypt]) is the act of extracting
information about data being sent through a network. While one may information about data being sent through a network. While directly
directly obscure the data through the use of encryption [RFC4303], obscuring the data with encryption [RFC4303], the traffic pattern
the traffic pattern itself exposes information due to variations in itself exposes information due to variations in its shape and timing
it's shape and timing ([I-D.iab-wire-image], [AppCrypt]). Hiding the ([RFC8546], [AppCrypt]). Hiding the size and frequency of traffic is
size and frequency of traffic is referred to as Traffic Flow referred to as Traffic Flow Confidentiality (TFC) per [RFC4303].
Confidentiality (TFC) per [RFC4303].
[RFC4303] provides for TFC by allowing padding to be added to [RFC4303] provides for TFC by allowing padding to be added to
encrypted IP packets and allowing for transmission of all-pad packets encrypted IP packets and allowing for transmission of all-pad packets
(indicated using protocol 59). This method has the major limitation (indicated using protocol 59). This method has the major limitation
that it can significantly under-utilize the available bandwidth. that it can significantly under-utilize the available bandwidth.
The IP-TFS solution provides for full TFC without the aforementioned The IP-TFS (IP Traffic Flow Security) solution provides for full TFC
bandwidth limitation. This is accomplished by using a constant-send- without the aforementioned bandwidth limitation. This is
rate IPsec [RFC4303] tunnel with fixed-sized encapsulating packets; accomplished by using a constant-send-rate IPsec [RFC4303] tunnel
however, these fixed-sized packets can contain partial, whole or with fixed-sized encapsulating packets; however, these fixed-sized
multiple IP packets to maximize the bandwidth of the tunnel. A non- packets can contain partial, whole or multiple IP packets to maximize
constant send-rate is allowed, but the confidentiality properties of the bandwidth of the tunnel. A non-constant send-rate is allowed,
its use are outside the scope of this document. but the confidentiality properties of its use are outside the scope
of this document.
For a comparison of the overhead of IP-TFS with the RFC4303 For a comparison of the overhead of IP-TFS with the RFC4303
prescribed TFC solution see Appendix C. prescribed TFC solution see Appendix C.
Additionally, IP-TFS provides for dealing with network congestion Additionally, IP-TFS provides for operating fairly within congested
[RFC2914]. This is important for when the IP-TFS user is not in full networks [RFC2914]. This is important for when the IP-TFS user is
control of the domain through which the IP-TFS tunnel path flows. not in full control of the domain through which the IP-TFS tunnel
path flows.
The mechanisms defined in this document are generic with the intent
of allowing for non-TFS uses, but such uses are outside the scope of
this document.
1.1. Terminology & Concepts 1.1. Terminology & Concepts
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in "OPTIONAL" in this document are to be interpreted as described in BCP
[RFC2119] [RFC8174] when, and only when, they appear in all capitals, 14 [RFC2119] [RFC8174] when, and only when, they appear in all
as shown here. capitals, as shown here.
This document assumes familiarity with IP security concepts described This document assumes familiarity with IP security concepts including
in [RFC4301]. TFC as described in [RFC4301].
2. The IP-TFS Tunnel 2. The IP-TFS Tunnel
As mentioned in Section 1 IP-TFS utilizes an IPsec [RFC4303] tunnel As mentioned in Section 1 IP-TFS utilizes an IPsec [RFC4303] tunnel
(SA) as it's transport. To provide for full TFC, fixed-sized as its transport. To provide for full TFC, fixed-sized encapsulating
encapsulating packets are sent at a constant rate on the tunnel. packets are sent at a constant rate on the tunnel.
The primary input to the tunnel algorithm is the requested bandwidth The primary input to the tunnel algorithm is the requested bandwidth
used by the tunnel. Two values are then required to provide for this to be used by the tunnel. Two values are then required to provide
bandwidth, the fixed size of the encapsulating packets, and rate at for this bandwidth use, the fixed size of the encapsulating packets,
which to send them. and rate at which to send them.
The fixed packet size MAY either be specified manually or could be The fixed packet size MAY either be specified manually or be
determined through the other methods such as the Packetization Layer determined through other methods such as the Packetization Layer MTU
MTU Discovery (PLMTUD) ([RFC4821], [RFC8899]) or Path MTU discovery Discovery (PLMTUD) ([RFC4821], [RFC8899]) or Path MTU discovery
(PMTUD) ([RFC1191], [RFC8201]). PMTUD is known to have issues so (PMTUD) ([RFC1191], [RFC8201]). PMTUD is known to have issues so
PLMTUD is considered the more robust option. PLMTUD is considered the more robust option. For PLMTUD, congestion
control payloads can be used as in-band probes (see Section 6.1.2 and
[RFC8899]).
Given the encapsulating packet size and the requested tunnel used Given the encapsulating packet size and the requested bandwidth to be
bandwidth, the corresponding packet send rate can be calculated. The used, the corresponding packet send rate can be calculated. The
packet send rate is the requested bandwidth divided by the size of packet send rate is the requested bandwidth to be used divided by the
the encapsulating packet. size of the encapsulating packet.
The egress of the IP-TFS tunnel MUST allow for and expect the ingress The egress (receiving) side of the IP-TFS tunnel MUST allow for and
(sending) side of the IP-TFS tunnel to vary the size and rate of sent expect the ingress (sending) side of the IP-TFS tunnel to vary the
encapsulating packets, unless constrained by other policy. size and rate of sent encapsulating packets, unless constrained by
other policy.
2.1. Tunnel Content 2.1. Tunnel Content
As previously mentioned, one issue with the TFC padding solution in As previously mentioned, one issue with the TFC padding solution in
[RFC4303] is the large amount of wasted bandwidth as only one IP [RFC4303] is the large amount of wasted bandwidth as only one IP
packet can be sent per encapsulating packet. In order to maximize packet can be sent per encapsulating packet. In order to maximize
bandwidth IP-TFS breaks this one-to-one association. bandwidth, IP-TFS breaks this one-to-one association.
IP-TFS aggregates as well as fragments the inner IP traffic flow into IP-TFS aggregates as well as fragments the inner IP traffic flow into
fixed-sized encapsulating IPsec tunnel packets. Padding is only fixed-sized encapsulating IPsec tunnel packets. Padding is only
added to the the tunnel packets if there is no data available to be added to the the tunnel packets if there is no data available to be
sent at the time of tunnel packet transmission, or if fragmentation sent at the time of tunnel packet transmission, or if fragmentation
has been disabled by the receiver. has been disabled by the receiver.
This is accomplished using a new Encapsulating Security Payload (ESP, This is accomplished using a new Encapsulating Security Payload (ESP,
[RFC4303]) type which is identified by the number AGGFRAG_PAYLOAD [RFC4303]) Next Header field value AGGFRAG_PAYLOAD (Section 6.1).
(Section 6.1).
Other non-IP-TFS uses of this aggregation and fragmentation Other non-IP-TFS uses of this aggregation and fragmentation
encapsulation have been identified, such as increased performance encapsulation have been identified, such as increased performance
through packet aggregation, as well as handling MTU issues using through packet aggregation, as well as handling MTU issues using
fragmentation. These uses are not defined here, but are also not fragmentation. These uses are not defined here, but are also not
restricted by this document. restricted by this document.
2.2. Payload Content 2.2. Payload Content
The AGGFRAG_PAYLOAD payload content defined in this document is The AGGFRAG_PAYLOAD payload content defined in this document is
comprised of a 4 or 24 octet header followed by either a partial, a comprised of a 4 or 24 octet header followed by either a partial
full or multiple partial or full data blocks. The following diagram datablock, a full datablock, or multiple partial or full datablocks.
illustrates this payload within the ESP packet. See Section 6.1 for The following diagram illustrates this payload within the ESP packet.
the exact formats of the AGGFRAG_PAYLOAD payload. See Section 6.1 for the exact formats of the AGGFRAG_PAYLOAD payload.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. Outer Encapsulating Header ... . . Outer Encapsulating Header ... .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. ESP Header... . . ESP Header... .
+---------------------------------------------------------------+ +---------------------------------------------------------------+
| [AGGFRAG subtype/flags] : BlockOffset | | [AGGFRAG subtype/flags] : BlockOffset |
+---------------------------------------------------------------+ +---------------------------------------------------------------+
: [Optional Congestion Info] : : [Optional Congestion Info] :
+---------------------------------------------------------------+ +---------------------------------------------------------------+
skipping to change at page 5, line 39 skipping to change at page 6, line 7
Figure 1: Layout of an IP-TFS IPsec Packet Figure 1: Layout of an IP-TFS IPsec Packet
The "BlockOffset" value is either zero or some offset into or past The "BlockOffset" value is either zero or some offset into or past
the end of the "DataBlocks" data. the end of the "DataBlocks" data.
If the "BlockOffset" value is zero it means that the "DataBlocks" If the "BlockOffset" value is zero it means that the "DataBlocks"
data begins with a new data block. data begins with a new data block.
Conversely, if the "BlockOffset" value is non-zero it points to the Conversely, if the "BlockOffset" value is non-zero it points to the
start of the new data block, and the initial "DataBlocks" data start of the new data block, and the initial "DataBlocks" data
belongs to a previous data block that is still being re-assembled. belongs to the data block that is still being re-assembled.
The "BlockOffset" can point past the end of the "DataBlocks" data If the "BlockOffset" points past the end of the "DataBlocks" data
which indicates that the next data block occurs in a subsequent then the next data block occurs in a subsequent encapsulating packet.
encapsulating packet.
Having the "BlockOffset" always point at the next available data Having the "BlockOffset" always point at the next available data
block allows for recovering the next inner packet in the presence of block allows for recovering the next inner packet in the presence of
outer encapsulating packet loss. outer encapsulating packet loss.
An example IP-TFS packet flow can be found in Appendix A. An example IP-TFS packet flow can be found in Appendix A.
2.2.1. Data Blocks 2.2.1. Data Blocks
+---------------------------------------------------------------+ +---------------------------------------------------------------+
| Type | rest of IPv4, IPv6 or pad. | Type | rest of IPv4, IPv6 or pad.
+-------- +--------
Figure 2: Layout of IP-TFS data block Figure 2: Layout of a DataBlock
A data block is defined by a 4-bit type code followed by the data A data block is defined by a 4-bit type code followed by the data
block data. The type values have been carefully chosen to coincide block data. The type values have been carefully chosen to coincide
with the IPv4/IPv6 version field values so that no per-data block with the IPv4/IPv6 version field values so that no per-data block
type overhead is required to encapsulate an IP packet. Likewise, the type overhead is required to encapsulate an IP packet. Likewise, the
length of the data block is extracted from the encapsulated IPv4 or length of the data block is extracted from the encapsulated IPv4's
IPv6 packet's length field. "Total Length" or IPv6's "Payload Length" fields.
2.2.2. No Implicit End Padding Required 2.2.2. End Padding
It's worth noting that since a data block type is identified by its Since a data block's type is identified in its first 4-bits, the only
first octet there is never a need for an implicit pad at the end of time padding is required is when there is no data to encapsulate.
an encapsulating packet. Even when the start of a data block occurs For this end padding a "Pad Data Block" is used.
near the end of a encapsulating packet such that there is no room for
the length field of the encapsulated header to be included in the
current encapsulating packet, the fact that the length comes at a
known location and is guaranteed to be present is enough to fetch the
length field from the subsequent encapsulating packet payload. Only
when there is no data to encapsulated is end padding required, and
then an explicit "Pad Data Block" would be used to identify the
padding.
2.2.3. Fragmentation, Sequence Numbers and All-Pad Payloads 2.2.3. Fragmentation, Sequence Numbers and All-Pad Payloads
In order for a receiver to be able to reassemble fragmented inner- In order for a receiver to reassemble fragmented inner-packets, the
packets, the sender MUST send the inner-packet fragments back-to-back sender MUST send the inner-packet fragments back-to-back in the
in the logical outer packet stream (i.e., using consecutive ESP logical outer packet stream (i.e., using consecutive ESP sequence
sequence numbers). However, the sender is allowed to insert "all- numbers). However, the sender is allowed to insert "all-pad"
pad" payloads (i.e., payloads with a "BlockOffset" of zero and a payloads (i.e., payloads with a "BlockOffset" of zero and a single
single pad "DataBlock") in between the packets carrying the inner- pad "DataBlock") in between the packets carrying the inner-packet
packet fragment payloads. This possible interleaving of all-pad fragment payloads. This interleaving of all-pad payloads allows the
payloads allows the sender to always be able to send a tunnel packet, sender to always send a tunnel packet, regardless of the
regardless of the encapsulation computational requirements. encapsulation computational requirements.
When a receiver is reassembling an inner-packet, and it receives an When a receiver is reassembling an inner-packet, and it receives an
"all-pad" payload, it increments the expected sequence number that "all-pad" payload, it increments the expected sequence number that
the next inner-packet fragment is expected to arrive in. the next inner-packet fragment is expected to arrive in.
Given the above, the receiver will need to handle out-of-order Given the above, the receiver will need to handle out-of-order
arrival of outer ESP packets prior to reassembly processing. ESP arrival of outer ESP packets prior to reassembly processing. ESP
already provides for optionally detecting replay attacks. Detecting already provides for optionally detecting replay attacks. Detecting
replay attacks normally utilizes a window method. A similar sequence replay attacks normally utilizes a window method. A similar sequence
number based sliding window can be used to correct re-ordering of the number based sliding window can be used to correct re-ordering of the
outer packet stream. Receiving a larger (newer) sequence number outer packet stream. Receiving a larger (newer) sequence number
packet advances the window, and received older ESP packets whose packet advances the window, and received older ESP packets whose
sequence numbers the window has passed by are dropped. A good choice sequence numbers the window has passed by are dropped. A good choice
for the size of this window depends on the amount of re-ordering the for the size of this window depends on the amount of re-ordering the
user may normally experience. user may normally experience.
As the amount of reordering that may be present is hard to predict As the amount of reordering that may be present is hard to predict,
the window size SHOULD be configurable by the user. Implementations the window size SHOULD be configurable by the user. Implementations
MAY also dynamically adjust the reordering window based on actual MAY also dynamically adjust the reordering window based on actual
reordering seen in arriving packets. Finally, we note that as IP-TFS reordering seen in arriving packets. Finally, note that as IP-TFS is
is sending a continuous stream of packets there is no requirement for sending a continuous stream of packets there is no requirement for
timers (although there's no prohibition either) as newly arrived timers (although there's no prohibition either) as newly arrived
packets will cause the window to advance and older packets will then packets will cause the window to advance and older packets will then
be processed as they leave the window. Implementations that are be processed as they leave the window. Implementations that are
concerned about memory use when packets are delayed (e.g., when an SA concerned about memory use when packets are delayed (e.g., when an SA
deletion is delayed) can of course use timers to drop packets as deletion is delayed) can of course use timers to drop packets as
well. well.
While ESP guarantees an increasing sequence number with subsequently While ESP guarantees an increasing sequence number with subsequently
sent packets, it does not actually require the sequence numbers to be sent packets, it does not actually require the sequence numbers to be
generated with no gaps (e.g., sending only even numbered sequence generated with no gaps (e.g., sending only even numbered sequence
numbers would be allowed as long as they are always increasing). numbers would be allowed as long as they are always increasing).
Gaps in the sequence numbers will not work for this specification so Gaps in the sequence numbers will not work for this document so the
the sequence number stream is further restricted to not contain gaps sequence number stream MUST increase monotonically by 1 for each
(i.e., each subsequent outer packet must be sent with the sequence subsequent packet.
number incremented by 1).
When using the AGGFRAG_PAYLOAD in conjunction with replay detection, When using the AGGFRAG_PAYLOAD in conjunction with replay detection,
the window size for both MAY be reduced to share the smaller of the the window size for both MAY be reduced to share the smaller of the
two window sizes. This is b/c packets outside of the smaller window two window sizes. This is because packets outside of the smaller
but inside the larger would still be dropped by the mechanism with window but inside the larger would still be dropped by the mechanism
the smaller window size. with the smaller window size.
Finally, as sequence numbers are reset when switching SAs (e.g., when Finally, as sequence numbers are reset when switching SAs (e.g., when
re-keying a child SA), an implementation SHOULD NOT send initial re-keying a child SA), senders MUST NOT send initial fragments of an
fragments of an inner packet using one SA and subsequent fragments in inner packet using one SA and subsequent fragments in a different SA.
a different SA.
2.2.3.1. Optional Extra Padding 2.2.3.1. Optional Extra Padding
When the tunnel bandwidth is not being fully utilized, an When the tunnel bandwidth is not being fully utilized, a sender MAY
implementation MAY pad-out the current encapsulating packet in order pad-out the current encapsulating packet in order to deliver an inner
to deliver an inner packet un-fragmented in the following outer packet un-fragmented in the following outer packet. The benefit
packet. The benefit would be to avoid inner-packet fragmentation in would be to avoid inner-packet fragmentation in the presence of a
the presence of a bursty offered load (non-bursty traffic will bursty offered load (non-bursty traffic will naturally not fragment).
naturally not fragment). An implementation MAY also choose to allow Senders MAY also choose to allow for a minimum fragment size to be
for a minimum fragment size to be configured (e.g., as a percentage configured (e.g., as a percentage of the AGGFRAG_PAYLOAD payload
of the AGGFRAG_PAYLOAD payload size) to avoid fragmentation at the size) to avoid fragmentation at the cost of tunnel bandwidth. The
cost of tunnel bandwidth. The cost with these methods is complexity cost with these methods is complexity and added delay of inner
and added delay of inner traffic. The main advantage to avoiding traffic. The main advantage to avoiding fragmentation is to minimize
fragmentation is to minimize inner packet loss in the presence of inner packet loss in the presence of outer packet loss. When this is
outer packet loss. When this is worthwhile (e.g., how much loss and worthwhile (e.g., how much loss and what type of loss is required,
what type of loss is required, given different inner traffic shapes given different inner traffic shapes and utilization, for this to
and utilization, for this to make sense), and what values to use for make sense), and what values to use for the allowable/added delay may
the allowable/added delay may be worth researching, but is outside be worth researching, but is outside the scope of this document.
the scope of this document.
While use of padding to avoid fragmentation does not impact While use of padding to avoid fragmentation does not impact
interoperability, used inappropriately it can reduce the effective interoperability, used inappropriately it can reduce the effective
throughput of a tunnel. Implementations implementing either of the throughput of a tunnel. Senders implementing either of the above
above approaches will need to take care to not reduce the effective approaches will need to take care to not reduce the effective
capacity, and overall utility, of the tunnel through the overuse of capacity, and overall utility, of the tunnel through the overuse of
padding. padding.
2.2.4. Empty Payload 2.2.4. Empty Payload
In order to support reporting of congestion control information To support reporting of congestion control information (described
(described later) on a non-AGGFRAG_PAYLOAD enabled SA, IP-TFS allows later) on a non-AGGFRAG_PAYLOAD enabled SA, IP-TFS allows for the
for the sending of an AGGFRAG_PAYLOAD payload with no data blocks sending of an AGGFRAG_PAYLOAD payload with no data blocks (i.e., the
(i.e., the ESP payload length is equal to the AGGFRAG_PAYLOAD header ESP payload length is equal to the AGGFRAG_PAYLOAD header length).
length). This special payload is called an empty payload. This special payload is called an empty payload.
Currently this situation is only applicable in non-IKEv2 use cases.
2.2.5. IP Header Value Mapping 2.2.5. IP Header Value Mapping
[RFC4301] provides some direction on when and how to map various [RFC4301] provides some direction on when and how to map various
values from an inner IP header to the outer encapsulating header, values from an inner IP header to the outer encapsulating header,
namely the Don't-Fragment (DF) bit ([RFC0791] and [RFC8200]), the namely the Don't-Fragment (DF) bit ([RFC0791] and [RFC8200]), the
Differentiated Services (DS) field [RFC2474] and the Explicit Differentiated Services (DS) field [RFC2474] and the Explicit
Congestion Notification (ECN) field [RFC3168]. Unlike [RFC4301], IP- Congestion Notification (ECN) field [RFC3168]. Unlike [RFC4301], IP-
TFS may and often will be encapsulating more than one IP packet per TFS may and often will be encapsulating more than one IP packet per
ESP packet. To deal with this, these mappings are restricted ESP packet. To deal with this, these mappings are restricted
further. In particular IP-TFS never maps the inner DF bit as it is further.
unrelated to the IP-TFS tunnel functionality; IP-TFS never IP
fragments the inner packets and the inner packets will not affect the
fragmentation of the outer encapsulation packets. Likewise, the ECN
value need not be mapped as any congestion related to the constant-
send-rate IP-TFS tunnel is unrelated (by design!) to the inner
traffic flow. Finally, by default the DS field SHOULD NOT be copied
although an implementation MAY choose to allow for configuration to
override this behavior. An implementation SHOULD also allow the DS
value to be set by configuration.
It is worth noting that an implementation MAY still set the ECN value 2.2.5.1. DF bit
of inner packets based on the normal ECN specification ([RFC3168]).
IP-TFS never maps the inner DF bit as it is unrelated to the IP-TFS
tunnel functionality; IP-TFS never needs to IP fragment the inner
packets and the inner packets will not affect the fragmentation of
the outer encapsulation packets.
2.2.5.2. ECN value
The ECN value need not be mapped as any congestion related to the
constant-send-rate IP-TFS tunnel is unrelated (by design) to the
inner traffic flow. The sender MAY still set the ECN value of inner
packets based on the normal ECN specification [RFC3168].
2.2.5.3. DS field
By default the DS field SHOULD NOT be copied, although a sender MAY
choose to allow for configuration to override this behavior. A
sender SHOULD also allow the DS value to be set by configuration.
2.2.6. IP Time-To-Live (TTL) and Tunnel errors 2.2.6. IP Time-To-Live (TTL) and Tunnel errors
[RFC4301] specifies how to modify the inner packet TTL ([RFC0791]). [RFC4301] specifies how to modify the inner packet TTL [RFC0791].
Any errors (e.g., ICMP errors arriving back at the tunnel ingress due Any errors (e.g., ICMP errors arriving back at the tunnel ingress due
to tunnel traffic) should be handled the same as with non IP-TFS to tunnel traffic) are handled the same as with non IP-TFS IPsec
IPsec tunnels. tunnels.
2.2.7. Effective MTU of the Tunnel 2.2.7. Effective MTU of the Tunnel
Unlike [RFC4301], there is normally no effective MTU (EMTU) on an IP- Unlike [RFC4301], there is normally no effective MTU (EMTU) on an IP-
TFS tunnel as all IP packet sizes are properly transmitted without TFS tunnel as all IP packet sizes are properly transmitted without
requiring IP fragmentation prior to tunnel ingress. That said, an requiring IP fragmentation prior to tunnel ingress. That said, a
implementation MAY allow for explicitly configuring an MTU for the sender MAY allow for explicitly configuring an MTU for the tunnel.
tunnel.
If IP-TFS fragmentation has been disabled, then the tunnel's EMTU and If IP-TFS fragmentation has been disabled, then the tunnel's EMTU and
behaviors are the same as normal IPsec tunnels ([RFC4301]). behaviors are the same as normal IPsec tunnels [RFC4301].
2.3. Exclusive SA Use 2.3. Exclusive SA Use
It is not the intention of this specification to allow for mixed use This document does not specify mixed use of an AGGFRAG_PAYLOAD
of an AGGFRAG_PAYLOAD enabled SA. In other words, an SA that has enabled SA. A sender MUST only send AGGFRAG_PAYLOAD payloads over an
AGGFRAG_PAYLOAD enabled MUST NOT have non-AGGFRAG_PAYLOAD payloads SA configured for AGGFRAG_PAYLOAD use.
such as IP (IP protocol 4), TCP transport (IP protocol 6), or ESP pad
packets (protocol 59) intermixed with non-empty AGGFRAG_PAYLOAD
payloads. Empty AGGFRAG_PAYLOAD payloads (Section 2.2.4) are used to
transmit congestion control information on non-IP-TFS enabled SAs, so
intermixing is allowed in this specific case. While it's possible to
envision making the algorithm work in the presence of sequence number
skips in the AGGFRAG_PAYLOAD payload stream, the added complexity is
not deemed worthwhile. Other IPsec uses can configure and use their
own SAs.
2.4. Modes of Operation 2.4. Modes of Operation
Just as with normal IPsec/ESP tunnels, IP-TFS tunnels are Just as with normal IPsec/ESP tunnels, IP-TFS tunnels are
unidirectional. Bidirectional IP-TFS functionality is achieved by unidirectional. Bidirectional IP-TFS functionality is achieved by
setting up 2 IP-TFS tunnels, one in either direction. setting up 2 IP-TFS tunnels, one in either direction.
An IP-TFS tunnel can operate in 2 modes, a non-congestion controlled An IP-TFS tunnel can operate in 2 modes, a non-congestion controlled
mode and congestion controlled mode. mode and congestion controlled mode.
2.4.1. Non-Congestion Controlled Mode 2.4.1. Non-Congestion Controlled Mode
In the non-congestion controlled mode IP-TFS sends fixed-sized In the non-congestion controlled mode, IP-TFS sends fixed-sized
packets at a constant rate. The packet send rate is constant and is packets at a constant rate. The packet send rate is constant and is
not automatically adjusted regardless of any network congestion not automatically adjusted regardless of any network congestion
(e.g., packet loss). (e.g., packet loss).
For similar reasons as given in [RFC7510] the non-congestion For similar reasons as given in [RFC7510] the non-congestion
controlled mode should only be used where the user has full controlled mode should only be used where the user has full
administrative control over the path the tunnel will take. This is administrative control over the path the tunnel will take. This is
required so the user can guarantee the bandwidth and also be sure as required so the user can guarantee the bandwidth and also be sure as
to not be negatively affecting network congestion [RFC2914]. In this to not be negatively affecting network congestion [RFC2914]. In this
case packet loss should be reported to the administrator (e.g., via case packet loss should be reported to the administrator (e.g., via
syslog, YANG notification, SNMP traps, etc) so that any failures due syslog, YANG notification, SNMP traps, etc) so that any failures due
to a lack of bandwidth can be corrected. to a lack of bandwidth can be corrected.
Non-congestion control mode is also appropriate if ESP over TCP is in
use [RFC8229].
2.4.2. Congestion Controlled Mode 2.4.2. Congestion Controlled Mode
With the congestion controlled mode, IP-TFS adapts to network With the congestion controlled mode, IP-TFS adapts to network
congestion by lowering the packet send rate to accommodate the congestion by lowering the packet send rate to accommodate the
congestion, as well as raising the rate when congestion subsides. congestion, as well as raising the rate when congestion subsides.
Since overhead is per packet, by allowing for maximal fixed-size Since overhead is per packet, by allowing for maximal fixed-size
packets and varying the send rate transport overhead is minimized. packets and varying the send rate transport overhead is minimized.
The output of the congestion control algorithm will adjust the rate The output of the congestion control algorithm will adjust the rate
at which the ingress sends packets. While this document does not at which the ingress sends packets. While this document does not
require a specific congestion control algorithm, best current require a specific congestion control algorithm, best current
practice RECOMMENDS that the algorithm conform to [RFC5348]. practice RECOMMENDS that the algorithm conform to [RFC5348].
Congestion control principles are documented in [RFC2914] as well. Congestion control principles are documented in [RFC2914] as well.
An example of an implementation of the [RFC5348] algorithm which [RFC4342] provides an example of the [RFC5348] algorithm which
matches the requirements of IP-TFS (i.e., designed for fixed-size matches the requirements of IP-TFS (i.e., designed for fixed-size
packet and send rate varied based on congestion) is documented in packet and send rate varied based on congestion.
[RFC4342].
The required inputs for the TCP friendly rate control algorithm The required inputs for the TCP friendly rate control algorithm
described in [RFC5348] are the receiver's loss event rate and the described in [RFC5348] are the receiver's loss event rate and the
sender's estimated round-trip time (RTT). These values are provided sender's estimated round-trip time (RTT). These values are provided
by IP-TFS using the congestion information header fields described in by IP-TFS using the congestion information header fields described in
Section 3. In particular these values are sufficient to implement Section 3. In particular, these values are sufficient to implement
the algorithm described in [RFC5348]. the algorithm described in [RFC5348].
At a minimum, the congestion information must be sent, from the At a minimum, the congestion information MUST be sent, from the
receiver and from the sender, at least once per RTT. Prior to receiver and from the sender, at least once per RTT. Prior to
establishing an RTT the information SHOULD be sent constantly from establishing an RTT the information SHOULD be sent constantly from
the sender and the receiver so that an RTT estimate can be the sender and the receiver so that an RTT estimate can be
established. The lack of receiving this information over multiple established. Not receiving this information over multiple
consecutive RTT intervals should be considered a congestion event consecutive RTT intervals should be considered a congestion event
that causes the sender to adjust it's sending rate lower. For that causes the sender to adjust its sending rate lower. For
example, [RFC4342] calls this the "no feedback timeout" and it is example, [RFC4342] calls this the "no feedback timeout" and it is
equal to 4 RTT intervals. When a "no feedback timeout" has occurred equal to 4 RTT intervals. When a "no feedback timeout" has occurred
[RFC4342] halves the sending rate. [RFC4342] halves the sending rate.
An implementation MAY choose to always include the congestion An implementation MAY choose to always include the congestion
information in it's IP-TFS payload header if sending on an IP-TFS information in its IP-TFS payload header if sending on an IP-TFS
enabled SA. Since IP-TFS normally will operate with a large packet enabled SA. Since IP-TFS normally will operate with a large packet
size, the congestion information should represent a small portion of size, the congestion information should represent a small portion of
the available tunnel bandwidth. An implementation choosing to always the available tunnel bandwidth. An implementation choosing to always
send the data MAY also choose to only update the "LossEventRate" and send the data MAY also choose to only update the "LossEventRate" and
"RTT" header field values it sends every "RTT" though. "RTT" header field values it sends every "RTT" though.
When an implementation is choosing a congestion control algorithm (or When choosing a congestion control algorithm (or a selection of
a selection of algorithms) one should remember that IP-TFS is not algorithms) note that IP-TFS is not providing for reliable delivery
providing for reliable delivery of IP traffic, and so per packet ACKs of IP traffic, and so per packet ACKs are not required and are not
are not required and are not provided. provided.
It's worth noting that the variable send-rate of a congestion It is worth noting that the variable send-rate of a congestion
controlled IP-TFS tunnel, is not private; however, this send-rate is controlled IP-TFS tunnel, is not private; however, this send-rate is
being driven by network congestion, and as long as the encapsulated being driven by network congestion, and as long as the encapsulated
(inner) traffic flow shape and timing are not directly affecting the (inner) traffic flow shape and timing are not directly affecting the
(outer) network congestion, the variations in the tunnel rate will (outer) network congestion, the variations in the tunnel rate will
not weaken the provided inner traffic flow confidentiality. not weaken the provided inner traffic flow confidentiality.
2.4.2.1. Circuit Breakers 2.4.2.1. Circuit Breakers
In additional to congestion control, implementations MAY choose to In additional to congestion control, implementations MAY choose to
define and implement circuit breakers [RFC8084] as a recovery method define and implement circuit breakers [RFC8084] as a recovery method
of last resort. Enabling circuit breakers is also a reason a user of last resort. Enabling circuit breakers is also a reason a user
may wish to enable congestion information reports even when using the may wish to enable congestion information reports even when using the
non-congestion controlled mode of operation. The definition of non-congestion controlled mode of operation. The definition of
circuit breakers are outside the scope of this document. circuit breakers are outside the scope of this document.
2.5. Summary of Receiver Processing
An IP-TFS receiver has a few tasks to perform.
The receiver first reorders, possibly out-of-order ESP packets
received on an SA into in-sequence-order AGGFRAG_PAYLOAD payloads
(Section 2.2.3). If congestion control is enabled, the receiver
considers a packet lost when it's sequence number is abandoned (e.g.,
pushed out of the re-ordering window, or timed-out) by the reordering
algorithm.
Additionally, if congestion control is enabled, the receiver sends
congestion control data (Section 6.1.2) back to the sender as
described in Section 2.4.2 and Section 3.
Finally, the receiver processes the now in-order AGGFRAG_PAYLOAD
payload stream to extract the inner-packets (Section 2.2.3,
Section 6.1).
3. Congestion Information 3. Congestion Information
In order to support the congestion control mode, the sender needs to In order to support the congestion control mode, the sender needs to
know the loss event rate and also be able to approximate the RTT know the loss event rate and to approximate the RTT [RFC5348]. In
([RFC5348]). In order to obtain these values the receiver sends order to obtain these values, the receiver sends congestion control
congestion control information on it's SA back to the sender. Thus, information on it's SA back to the sender. Thus, to support
in order to support congestion control the receiver must have a congestion control the receiver must have a paired SA back to the
paired SA back to the sender (this is always the case when the tunnel sender (this is always the case when the tunnel was created using
was created using IKEv2). If the SA back to the sender is a non- IKEv2). If the SA back to the sender is a non-AGGFRAG_PAYLOAD
AGGFRAG_PAYLOAD enabled SA then an AGGFRAG_PAYLOAD empty payload enabled SA then an AGGFRAG_PAYLOAD empty payload (i.e., header only)
(i.e., header only) is used to convey the information. is used to convey the information.
In order to calculate a loss event rate compatible with [RFC5348], In order to calculate a loss event rate compatible with [RFC5348],
the receiver needs to have a round-trip time estimate. Thus the the receiver needs to have a round-trip time estimate. Thus the
sender communicates this estimate in the "RTT" header field. On sender communicates this estimate in the "RTT" header field. On
startup this value will be zero as no RTT estimate is yet known. startup this value will be zero as no RTT estimate is yet known.
In order for the sender to estimate it's "RTT" value, the sender In order for the sender to estimate its "RTT" value, the sender
places a timestamp value in the "TVal" header field. On first places a timestamp value in the "TVal" header field. On first
receipt of this "TVal", the receiver records the new "TVal" value receipt of this "TVal", the receiver records the new "TVal" value
along with the time it arrived locally, subsequent receipt of the along with the time it arrived locally, subsequent receipt of the
same "TVal" MUST not update the recorded time. When the receiver same "TVal" MUST NOT update the recorded time.
sends it's CC header it places this latest recorded value in the
"TEcho" header field, along with 2 delay values, "Echo Delay" and When the receiver sends its CC header it places this latest recorded
"Transmit Delay". The "Echo Delay" value is the time delta from the "TVal" in the "TEcho" header field, along with 2 delay values, "Echo
recorded arrival time of "TVal" and the current clock in Delay" and "Transmit Delay". The "Echo Delay" value is the time
microseconds. The second value, "Transmit Delay", is the receiver's delta from the recorded arrival time of "TVal" and the current clock
current transmission delay on the tunnel (i.e., the average time in microseconds. The second value, "Transmit Delay", is the
between sending packets on it's half of the IP-TFS tunnel). When the receiver's current transmission delay on the tunnel (i.e., the
sender receives back it's "TVal" in the "TEcho" header field it average time between sending packets on its half of the IP-TFS
calculates 2 RTT estimates. The first is the actual delay found by tunnel).
subtracting the "TEcho" value from it's current clock and then
When the sender receives back its "TVal" in the "TEcho" header field
it calculates 2 RTT estimates. The first is the actual delay found
by subtracting the "TEcho" value from its current clock and then
subtracting "Echo Delay" as well. The second RTT estimate is found subtracting "Echo Delay" as well. The second RTT estimate is found
by adding the received "Transmit Delay" header value to the senders by adding the received "Transmit Delay" header value to the senders
own transmission delay (i.e., the average time between sending own transmission delay (i.e., the average time between sending
packets on it's half of the IP-TFS tunnel). The larger of these 2 packets on its half of the IP-TFS tunnel). The larger of these 2 RTT
RTT estimates SHOULD be used as the "RTT" value. The two estimates estimates SHOULD be used as the "RTT" value.
are required to handle different combinations of faster or slower
tunnel packet paths with faster or slower fixed tunnel rates. The two RTT estimates are required to handle different combinations
Choosing the larger of the two values guarantees that the "RTT" is of faster or slower tunnel packet paths with faster or slower fixed
never considered faster than the aggregate transmission delay based tunnel rates. Choosing the larger of the two values guarantees that
on the IP-TFS tunnel rate (the second estimate), as well as never the "RTT" is never considered faster than the aggregate transmission
being considered faster than the actual RTT along the tunnel packet delay based on the IP-TFS tunnel rate (the second estimate), as well
path (the first estimate). as never being considered faster than the actual RTT along the tunnel
packet path (the first estimate).
The receiver also calculates, and communicates in the "LossEventRate" The receiver also calculates, and communicates in the "LossEventRate"
header field, the loss event rate for use by the sender. This is header field, the loss event rate for use by the sender. This is
slightly different from [RFC4342] which periodically sends all the slightly different from [RFC4342] which periodically sends all the
loss interval data back to the sender so that it can do the loss interval data back to the sender so that it can do the
calculation. See Appendix B for a suggested way to calculate the calculation. See Appendix B for a suggested way to calculate the
loss event rate value. Initially this value will be zero (indicating loss event rate value. Initially this value will be zero (indicating
no loss) until enough data has been collected by the receiver to no loss) until enough data has been collected by the receiver to
update it. update it.
3.1. ECN Support 3.1. ECN Support
In additional to normal packet loss information IP-TFS supports use In additional to normal packet loss information IP-TFS supports use
of the ECN bits in the encapsulating IP header [RFC3168] for of the ECN bits in the encapsulating IP header [RFC3168] for
identifying congestion. If ECN use is enabled and a packet arrives identifying congestion. If ECN use is enabled and a packet arrives
at the egress endpoint with the Congestion Experienced (CE) value at the egress (receiving) side with the Congestion Experienced (CE)
set, then the receiver considers that packet as being dropped, value set, then the receiver considers that packet as being dropped,
although it does not drop it. The receiver MUST set the E bit in any although it does not drop it. The receiver MUST set the E bit in any
AGGFRAG_PAYLOAD payload header containing a "LossEventRate" value AGGFRAG_PAYLOAD payload header containing a "LossEventRate" value
derived from a CE value being considered. derived from a CE value being considered.
As noted in [RFC3168] the ECN bits are not protected by IPsec and As noted in [RFC3168] the ECN bits are not protected by IPsec and
thus may constitute a covert channel. For this reason ECN use SHOULD thus may constitute a covert channel. For this reason, ECN use
NOT be enabled by default. SHOULD NOT be enabled by default.
4. Configuration 4. Configuration
IP-TFS is meant to be deployable with a minimal amount of IP-TFS is meant to be deployable with a minimal amount of
configuration. All IP-TFS specific configuration should be able to configuration. All IP-TFS specific configuration should be specified
be specified at the unidirectional tunnel ingress (sending) side. It at the unidirectional tunnel ingress (sending) side. It is intended
is intended that non-IKEv2 operation is supported, at least, with that non-IKEv2 operation is supported, at least, with local static
local static configuration. configuration.
4.1. Bandwidth 4.1. Bandwidth
Bandwidth is a local configuration option. For non-congestion Bandwidth is a local configuration option. For non-congestion
controlled mode the bandwidth SHOULD be configured. For congestion controlled mode, the bandwidth SHOULD be configured. For congestion
controlled mode one can configure the bandwidth or have no controlled mode, the bandwidth can be configured or the congestion
configuration and let congestion control discover the maximum control algorithm discovers and uses the maximum bandwidth available.
bandwidth available. No standardized configuration method is No standardized configuration method is required.
required.
4.2. Fixed Packet Size 4.2. Fixed Packet Size
The fixed packet size to be used for the tunnel encapsulation packets The fixed packet size to be used for the tunnel encapsulation packets
MAY be configured manually or can be automatically determined using MAY be configured manually or can be automatically determined using
other methods such as PLMTUD ([RFC4821], [RFC8899]) or PMTUD other methods such as PLMTUD ([RFC4821], [RFC8899]) or PMTUD
([RFC1191], [RFC8201]). As PMTUD is known to have issues, PLMTUD is ([RFC1191], [RFC8201]). As PMTUD is known to have issues, PLMTUD is
considered the more robust option. No standardized configuration considered the more robust option. No standardized configuration
method is required. method is required.
skipping to change at page 13, line 47 skipping to change at page 14, line 42
Congestion control is a local configuration option. No standardized Congestion control is a local configuration option. No standardized
configuration method is required. configuration method is required.
5. IKEv2 5. IKEv2
5.1. USE_AGGFRAG Notification Message 5.1. USE_AGGFRAG Notification Message
As mentioned previously IP-TFS tunnels utilize ESP payloads of type As mentioned previously IP-TFS tunnels utilize ESP payloads of type
AGGFRAG_PAYLOAD. AGGFRAG_PAYLOAD.
When using IKEv2, a new "USE_AGGFRAG" Notification Message is used to When using IKEv2, a new "USE_AGGFRAG" Notification Message enables
enable use of the AGGFRAG_PAYLOAD payload on a child SA pair. The the AGGFRAG_PAYLOAD payload on a child SA pair. The method used is
method used is similar to how USE_TRANSPORT_MODE is negotiated, as similar to how USE_TRANSPORT_MODE is negotiated, as described in
described in [RFC7296]. [RFC7296].
To request using the AGGFRAG_PAYLOAD payload on the Child SA pair, To request use of the AGGFRAG_PAYLOAD payload on the Child SA pair,
the initiator includes the USE_AGGFRAG notification in an SA payload the initiator includes the USE_AGGFRAG notification in an SA payload
requesting a new Child SA (either during the initial IKE_AUTH or requesting a new Child SA (either during the initial IKE_AUTH or
during non-rekeying CREATE_CHILD_SA exchanges). If the request is during CREATE_CHILD_SA exchanges). If the request is accepted then
accepted then response MUST also include a notification of type the response MUST also include a notification of type USE_AGGFRAG.
USE_AGGFRAG. If the responder declines the request the child SA will If the responder declines the request the child SA will be
be established without AGGFRAG_PAYLOAD payload use enabled. If this established without AGGFRAG_PAYLOAD payload use enabled. If this is
is unacceptable to the initiator, the initiator MUST delete the child unacceptable to the initiator, the initiator MUST delete the child
SA. SA.
The USE_AGGFRAG notification MUST NOT be sent, and MUST be ignored, As the use of the AGGFRAG_PAYLOAD payload is currently only defined
during a CREATE_CHILD_SA rekeying exchange as it is not allowed to for non-transport mode tunnels, the USE_AGGFRAG notification MUST NOT
change use of the AGGFRAG_PAYLOAD payload type during rekeying. A be combined with USE_TRANSPORT notification.
new child SA due to re-keying inherits the use of AGGFRAG_PAYLOAD
from the re-keyed child SA.
The USE_AGGFRAG notification contains a 1 octet payload of flags that The USE_AGGFRAG notification contains a 1 octet payload of flags that
specify any requirements from the sender of the message. If any specify requirements from the sender of the notification. If any
requirement flags are not understood or cannot be supported by the requirement flags are not understood or cannot be supported by the
receiver then the receiver should not enable use of AGGFRAG_PAYLOAD receiver then the receiver SHOULD NOT enable use of AGGFRAG_PAYLOAD
payload type (either by not responding with the USE_AGGFRAG (either by not responding with the USE_AGGFRAG notification, or in
notification, or in the case of the initiator, by deleting the child the case of the initiator, by deleting the child SA if the now
SA if the now established non-AGGFRAG_PAYLOAD using SA is established non-AGGFRAG_PAYLOAD using SA is unacceptable).
unacceptable).
The notification type and payload flag values are defined in The notification type and payload flag values are defined in
Section 6.1.4. Section 6.1.4.
6. Packet and Data Formats 6. Packet and Data Formats
The packet and data formats defined below are generic with the intent
of allowing for non-IP-TFS uses, but such uses are outside the scope
of this document.
6.1. AGGFRAG_PAYLOAD Payload 6.1. AGGFRAG_PAYLOAD Payload
ESP Payload Type: 0x5 ESP Next Header value: 0x5
An IP-TFS payload is identified by the ESP payload type An IP-TFS payload is identified by the ESP Next Header value
AGGFRAG_PAYLOAD which has the value 0x5. The first octet of this AGGFRAG_PAYLOAD which has the value 0x5. The value 5 was chosen to
payload indicates the format of the remaining payload data. not conflict with other used values. The first octet of this payload
indicates the format of the remaining payload data.
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-+-+-
| Sub-type | ... | Sub-type | ...
+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-+-+-
Sub-type: Sub-type:
An 8 bit value indicating the payload format. An 8-bit value indicating the payload format.
This specification defines 2 payload sub-types. These payload This document defines 2 payload sub-types. These payload formats are
formats are defined in the following sections. defined in the following sections.
6.1.1. Non-Congestion Control AGGFRAG_PAYLOAD Payload Format 6.1.1. Non-Congestion Control AGGFRAG_PAYLOAD Payload Format
The non-congestion control AGGFRAG_PAYLOAD payload is comprised of a The non-congestion control AGGFRAG_PAYLOAD payload is comprised of a
4 octet header followed by a variable amount of "DataBlocks" data as 4 octet header followed by a variable amount of "DataBlocks" data as
shown below. shown below.
1 2 3 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 15, line 27 skipping to change at page 16, line 27
+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-+-+-
Sub-type: Sub-type:
An octet indicating the payload format. For this non-congestion An octet indicating the payload format. For this non-congestion
control format, the value is 0. control format, the value is 0.
Reserved: Reserved:
An octet set to 0 on generation, and ignored on receipt. An octet set to 0 on generation, and ignored on receipt.
BlockOffset: BlockOffset:
A 16 bit unsigned integer counting the number of octets of A 16-bit unsigned integer counting the number of octets of
"DataBlocks" data before the start of a new data block. "DataBlocks" data before the start of a new data block. If the
"BlockOffset" can count past the end of the "DataBlocks" data in start of a new data block occurs in a subsequent payload the
which case all the "DataBlocks" data belongs to the previous data "BlockOffset" will point past the end of the "DataBlocks" data.
block being re-assembled. If the "BlockOffset" extends into In this case all the "DataBlocks" data belongs to the current data
subsequent packets it continues to only count subsequent block being assembled. When the "BlockOffset" extends into
"DataBlocks" data (i.e., it does not count subsequent packets subsequent payloads it continues to only count "DataBlocks" data
non-"DataBlocks" octets). (i.e., it does not count subsequent packets non-"DataBlocks" data
such as header octets).
DataBlocks: DataBlocks:
Variable number of octets that begins with the start of a data Variable number of octets that begins with the start of a data
block, or the continuation of a previous data block, followed by block, or the continuation of a previous data block, followed by
zero or more additional data blocks. zero or more additional data blocks.
6.1.2. Congestion Control AGGFRAG_PAYLOAD Payload Format 6.1.2. Congestion Control AGGFRAG_PAYLOAD Payload Format
The congestion control AGGFRAG_PAYLOAD payload is comprised of a 24 The congestion control AGGFRAG_PAYLOAD payload is comprised of a 24
octet header followed by a variable amount of "DataBlocks" data as octet header followed by a variable amount of "DataBlocks" data as
shown below. shown below.
1 2 3 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-type (1) | Reserved |E| BlockOffset | | Sub-type (1) | Reserved |P|E| BlockOffset |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LossEventRate | | LossEventRate |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RTT | Echo Delay ... | RTT | Echo Delay ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
... Echo Delay | Transmit Delay | ... Echo Delay | Transmit Delay |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TVal | | TVal |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TEcho | | TEcho |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DataBlocks ... | DataBlocks ...
+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-+-+-
Sub-type: Sub-type:
An octet indicating the payload format. For this congestion An octet indicating the payload format. For this congestion
control format, the value is 1. control format, the value is 1.
Reserved: Reserved:
A 7 bit field set to 0 on generation, and ignored on receipt. A 6-bit field set to 0 on generation, and ignored on receipt.
P:
A 1-bit value if set indicates that PLMTUD probing is in progress.
This information can be used to avoid treating missing packets as
loss events by the CC algorithm when running the PLMTUD probe
algorithm.
E: E:
A 1 bit value if set indicates that Congestion Experienced (CE) A 1-bit value if set indicates that Congestion Experienced (CE)
ECN bits were received and used in deriving the reported ECN bits were received and used in deriving the reported
"LossEventRate". "LossEventRate".
BlockOffset: BlockOffset:
The same value as the non-congestion controlled payload format The same value as the non-congestion controlled payload format
value. value.
LossEventRate: LossEventRate:
A 32 bit value specifying the inverse of the current loss event A 32-bit value specifying the inverse of the current loss event
rate as calculated by the receiver. A value of zero indicates no rate as calculated by the receiver. A value of zero indicates no
loss. Otherwise the loss event rate is "1/LossEventRate". loss. Otherwise the loss event rate is "1/LossEventRate".
RTT: RTT:
A 22 bit value specifying the sender's current round-trip time A 22-bit value specifying the sender's current round-trip time
estimate in microseconds. The value MAY be zero prior to the estimate in microseconds. The value MAY be zero prior to the
sender having calculated a round-trip time estimate. The value sender having calculated a round-trip time estimate. The value
SHOULD be set to zero on non-AGGFRAG_PAYLOAD enabled SAs. If the SHOULD be set to zero on non-AGGFRAG_PAYLOAD enabled SAs. If the
value is equal to or larger than "0x3FFFFF" it MUST be set to value is equal to or larger than "0x3FFFFF" it MUST be set to
"0x3FFFFF". "0x3FFFFF".
Echo Delay: Echo Delay:
A 21-bit value specifying the delay in microseconds incurred
A 21 bit value specifying the delay in microseconds incurred
between the receiver first receiving the "TVal" value which it is between the receiver first receiving the "TVal" value which it is
sending back in "TEcho". If the value is equal to or larger than sending back in "TEcho". If the value is equal to or larger than
"0x1FFFFF" it MUST be set to "0x1FFFFF". "0x1FFFFF" it MUST be set to "0x1FFFFF".
Transmit Delay: Transmit Delay:
A 21 bit value specifying the transmission delay in microseconds. A 21-bit value specifying the transmission delay in microseconds.
This is the fixed (or average) delay on the receiver between it This is the fixed (or average) delay on the receiver between it
sending packets on the IPTFS tunnel. If the value is equal to or sending packets on the IPTFS tunnel. If the value is equal to or
larger than "0x1FFFFF" it MUST be set to "0x1FFFFF". larger than "0x1FFFFF" it MUST be set to "0x1FFFFF".
TVal: TVal:
An opaque 32 bit value that will be echoed back by the receiver in An opaque 32-bit value that will be echoed back by the receiver in
later packets in the "TEcho" field, along with an "Echo Delay" later packets in the "TEcho" field, along with an "Echo Delay"
value of how long that echo took. value of how long that echo took.
TEcho: TEcho:
The opaque 32 bit value from a received packet's "TVal" field. The opaque 32-bit value from a received packet's "TVal" field.
The received "TVal" is placed in "TEcho" along with an "Echo The received "TVal" is placed in "TEcho" along with an "Echo
Delay" value indicating how long it has been since receiving the Delay" value indicating how long it has been since receiving the
"TVal" value. "TVal" value.
DataBlocks: DataBlocks:
Variable number of octets that begins with the start of a data Variable number of octets that begins with the start of a data
block, or the continuation of a previous data block, followed by block, or the continuation of a previous data block, followed by
zero or more additional data blocks. For the special case of zero or more additional data blocks. For the special case of
sending congestion control information on an non-IP-TFS enabled SA sending congestion control information on an non-IP-TFS enabled SA
this value MUST be empty (i.e., be zero octets long). this value MUST be empty (i.e., be zero octets long).
6.1.3. Data Blocks 6.1.3. Data Blocks
1 2 3 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | IPv4, IPv6 or pad... | Type | IPv4, IPv6 or pad...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
Type: Type:
A 4 bit field where 0x0 identifies a pad data block, 0x4 indicates A 4-bit field where 0x0 identifies a pad data block, 0x4 indicates
an IPv4 data block, and 0x6 indicates an IPv6 data block. an IPv4 data block, and 0x6 indicates an IPv6 data block.
6.1.3.1. IPv4 Data Block 6.1.3.1. IPv4 Data Block
1 2 3 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x4 | IHL | TypeOfService | TotalLength | | 0x4 | IHL | TypeOfService | TotalLength |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Rest of the inner packet ... | Rest of the inner packet ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
These values are the actual values within the encapsulated IPv4 These values are the actual values within the encapsulated IPv4
header. In other words, the start of this data block is the start of header. In other words, the start of this data block is the start of
the encapsulated IP packet. the encapsulated IP packet.
Type: Type:
A 4 bit value of 0x4 indicating IPv4 (i.e., first nibble of the A 4-bit value of 0x4 indicating IPv4 (i.e., first nibble of the
IPv4 packet). IPv4 packet).
TotalLength: TotalLength:
The 16 bit unsigned integer "Total Length" field of the IPv4 inner The 16-bit unsigned integer "Total Length" field of the IPv4 inner
packet. packet.
6.1.3.2. IPv6 Data Block 6.1.3.2. IPv6 Data Block
1 2 3 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x6 | TrafficClass | FlowLabel | | 0x6 | TrafficClass | FlowLabel |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PayloadLength | Rest of the inner packet ... | PayloadLength | Rest of the inner packet ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
These values are the actual values within the encapsulated IPv6 These values are the actual values within the encapsulated IPv6
header. In other words, the start of this data block is the start of header. In other words, the start of this data block is the start of
the encapsulated IP packet. the encapsulated IP packet.
Type: Type:
A 4 bit value of 0x6 indicating IPv6 (i.e., first nibble of the A 4-bit value of 0x6 indicating IPv6 (i.e., first nibble of the
IPv6 packet). IPv6 packet).
PayloadLength: PayloadLength:
The 16 bit unsigned integer "Payload Length" field of the inner The 16-bit unsigned integer "Payload Length" field of the inner
IPv6 inner packet. IPv6 inner packet.
6.1.3.3. Pad Data Block 6.1.3.3. Pad Data Block
1 2 3 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x0 | Padding ... | 0x0 | Padding ...
+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-+-+-
Type: Type:
A 4 bit value of 0x0 indicating a padding data block. A 4-bit value of 0x0 indicating a padding data block.
Padding: Padding:
extends to end of the encapsulating packet. Extends to end of the encapsulating packet.
6.1.4. IKEv2 USE_AGGFRAG Notification Message 6.1.4. IKEv2 USE_AGGFRAG Notification Message
As discussed in Section 5.1 a notification message USE_AGGFRAG is As discussed in Section 5.1, a notification message USE_AGGFRAG is
used to negotiate use of the ESP AGGFRAG_PAYLOAD payload type. used to negotiate use of the ESP AGGFRAG_PAYLOAD Next Header value.
The USE_AGGFRAG Notification Message State Type is (TBD2). The USE_AGGFRAG Notification Message State Type is (TBD2).
The notification payload contains 1 octet of requirement flags. The notification payload contains 1 octet of requirement flags.
There are currently 2 requirement flags defined. This may be revised There are currently 2 requirement flags defined. This may be revised
by later specifications. by later specifications.
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|0|0|0|0|0|0|C|D| |0|0|0|0|0|0|C|D|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
skipping to change at page 19, line 41 skipping to change at page 20, line 44
0: 0:
6 bits - reserved, MUST be zero on send, unless defined by later 6 bits - reserved, MUST be zero on send, unless defined by later
specifications. specifications.
C: C:
Congestion Control bit. If set, then the sender is requiring that Congestion Control bit. If set, then the sender is requiring that
congestion control information MUST be returned to it periodically congestion control information MUST be returned to it periodically
as defined in Section 3. as defined in Section 3.
D: D:
Don't Fragment bit, if set indicates the sender of the notify Don't Fragment bit. If set, indicates the sender of the notify
message does not support receiving packet fragments (i.e., inner message does not support receiving packet fragments (i.e., inner
packets MUST be sent using a single "Data Block"). This value packets MUST be sent using a single "Data Block"). This value
only applies to what the sender is capable of receiving; the only applies to what the sender is capable of receiving; the
sender MAY still send packet fragments unless similarly restricted sender MAY still send packet fragments unless similarly restricted
by the receiver in it's USE_AGGFRAG notification. by the receiver in it's USE_AGGFRAG notification.
7. IANA Considerations 7. IANA Considerations
7.1. AGGFRAG_PAYLOAD Sub-Type Registry 7.1. AGGFRAG_PAYLOAD Sub-Type Registry
This document requests IANA create a registry called "AGGFRAG_PAYLOAD This document requests IANA create a registry called "AGGFRAG_PAYLOAD
Sub-Type Registry" under a new category named "ESP AGGFRAG_PAYLOAD Sub-Type Registry" under a new category named "ESP AGGFRAG_PAYLOAD
Parameters". The registration policy for this registry is "Standards Parameters". The registration policy for this registry is "Expert
Action" ([RFC8126] and [RFC7120]). Review" ([RFC8126] and [RFC7120]).
Name: Name:
AGGFRAG_PAYLOAD Sub-Type Registry AGGFRAG_PAYLOAD Sub-Type Registry
Description: Description:
AGGFRAG_PAYLOAD Payload Formats. AGGFRAG_PAYLOAD Payload Formats.
Reference: Reference:
This document This document
skipping to change at page 20, line 47 skipping to change at page 21, line 47
TBD2 TBD2
Name: Name:
USE_AGGFRAG USE_AGGFRAG
Reference: Reference:
This document This document
8. Security Considerations 8. Security Considerations
This document describes a mechanism to add Traffic Flow This document describes a mechanism to add TFC to IP traffic. Use of
Confidentiality to IP traffic. Use of this mechanism is expected to this mechanism is expected to increase the security of the traffic
increase the security of the traffic being transported. Other than being transported. Other than the additional security afforded by
the additional security afforded by using this mechanism, IP-TFS using this mechanism, IP-TFS utilizes the security protocols
utilizes the security protocols [RFC4303] and [RFC7296] and so their [RFC4303] and [RFC7296] and so their security considerations apply to
security considerations apply to IP-TFS as well. IP-TFS as well.
As noted in (Section 3.1) the ECN bits are not protected by IPsec and
thus may constitute a covert channel. For this reason, ECN use
SHOULD NOT be enabled by default.
As noted previously in Section 2.4.2, for TFC to be fully maintained As noted previously in Section 2.4.2, for TFC to be fully maintained
the encapsulated traffic flow should not be affecting network the encapsulated traffic flow should not be affecting network
congestion in a predictable way, and if it would be then non- congestion in a predictable way, and if it would be then non-
congestion controlled mode use should be considered instead. congestion controlled mode use should be considered instead.
9. References 9. References
9.1. Normative References 9.1. Normative References
skipping to change at page 21, line 38 skipping to change at page 22, line 42
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
9.2. Informative References 9.2. Informative References
[AppCrypt] [AppCrypt]
Schneier, B., "Applied Cryptography: Protocols, Schneier, B., "Applied Cryptography: Protocols,
Algorithms, and Source Code in C", 11 2017. Algorithms, and Source Code in C", 11 2017.
[I-D.iab-wire-image]
Trammell, B. and M. Kuehlewind, "The Wire Image of a
Network Protocol", draft-iab-wire-image-01 (work in
progress), November 2018.
[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, [RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791,
DOI 10.17487/RFC0791, September 1981, DOI 10.17487/RFC0791, September 1981,
<https://www.rfc-editor.org/info/rfc791>. <https://www.rfc-editor.org/info/rfc791>.
[RFC1191] Mogul, J. and S. Deering, "Path MTU discovery", RFC 1191, [RFC1191] Mogul, J. and S. Deering, "Path MTU discovery", RFC 1191,
DOI 10.17487/RFC1191, November 1990, DOI 10.17487/RFC1191, November 1990,
<https://www.rfc-editor.org/info/rfc1191>. <https://www.rfc-editor.org/info/rfc1191>.
[RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black, [RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS "Definition of the Differentiated Services Field (DS
skipping to change at page 23, line 20 skipping to change at page 24, line 20
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200, (IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017, DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/info/rfc8200>. <https://www.rfc-editor.org/info/rfc8200>.
[RFC8201] McCann, J., Deering, S., Mogul, J., and R. Hinden, Ed., [RFC8201] McCann, J., Deering, S., Mogul, J., and R. Hinden, Ed.,
"Path MTU Discovery for IP version 6", STD 87, RFC 8201, "Path MTU Discovery for IP version 6", STD 87, RFC 8201,
DOI 10.17487/RFC8201, July 2017, DOI 10.17487/RFC8201, July 2017,
<https://www.rfc-editor.org/info/rfc8201>. <https://www.rfc-editor.org/info/rfc8201>.
[RFC8229] Pauly, T., Touati, S., and R. Mantha, "TCP Encapsulation
of IKE and IPsec Packets", RFC 8229, DOI 10.17487/RFC8229,
August 2017, <https://www.rfc-editor.org/info/rfc8229>.
[RFC8546] Trammell, B. and M. Kuehlewind, "The Wire Image of a
Network Protocol", RFC 8546, DOI 10.17487/RFC8546, April
2019, <https://www.rfc-editor.org/info/rfc8546>.
[RFC8899] Fairhurst, G., Jones, T., Tuexen, M., Ruengeler, I., and [RFC8899] Fairhurst, G., Jones, T., Tuexen, M., Ruengeler, I., and
T. Voelker, "Packetization Layer Path MTU Discovery for T. Voelker, "Packetization Layer Path MTU Discovery for
Datagram Transports", RFC 8899, DOI 10.17487/RFC8899, Datagram Transports", RFC 8899, DOI 10.17487/RFC8899,
September 2020, <https://www.rfc-editor.org/info/rfc8899>. September 2020, <https://www.rfc-editor.org/info/rfc8899>.
Appendix A. Example Of An Encapsulated IP Packet Flow Appendix A. Example Of An Encapsulated IP Packet Flow
Below an example inner IP packet flow within the encapsulating tunnel Below an example inner IP packet flow within the encapsulating tunnel
packet stream is shown. Notice how encapsulated IP packets can start packet stream is shown. Notice how encapsulated IP packets can start
and end anywhere, and more than one or less than 1 may occur in a and end anywhere, and more than one or less than 1 may occur in a
skipping to change at page 24, line 35 skipping to change at page 25, line 42
The IP-TFS receiver, having the RTT estimate from the sender can use The IP-TFS receiver, having the RTT estimate from the sender can use
the same method as described in [RFC5348] and [RFC4342] to collect the same method as described in [RFC5348] and [RFC4342] to collect
the loss intervals and calculate the loss event rate value using the the loss intervals and calculate the loss event rate value using the
weighted average as indicated. The receiver communicates the inverse weighted average as indicated. The receiver communicates the inverse
of this value back to the sender in the AGGFRAG_PAYLOAD payload of this value back to the sender in the AGGFRAG_PAYLOAD payload
header field "LossEventRate". header field "LossEventRate".
The IP-TFS sender now has both the "R" and "p" values and can The IP-TFS sender now has both the "R" and "p" values and can
calculate the correct sending rate. If following [RFC5348] the calculate the correct sending rate. If following [RFC5348] the
sender SHOULD also use the slow start mechanism described therein sender should also use the slow start mechanism described therein
when the IP-TFS SA is first established. when the IP-TFS SA is first established.
Appendix C. Comparisons of IP-TFS Appendix C. Comparisons of IP-TFS
C.1. Comparing Overhead C.1. Comparing Overhead
For comparing overhead the overhead of ESP for both normal and IP-TFS
tunnel packets must be calculated, and so an algorithm for encryption
and authentication must be chosen. For the data below AES-GCM-256
was selected. This leads to an IP+ESP overhead of 54.
54 = 20 (IP) + 8 (ESPH) + 2 (ESPF) + 8 (IV) + 16 (ICV)
Additionally, for IP-TFS, non-congestion control AGGFRAG_PAYLOAD
headers were chosen which adds 4 octets for a total overhead of 58.
C.1.1. IP-TFS Overhead C.1.1. IP-TFS Overhead
The overhead of IP-TFS is 40 bytes per outer packet. Therefore the For comparison the overhead of IP-TFS is 58 octets per outer packet.
octet overhead per inner packet is 40 divided by the number of outer Therefore the octet overhead per inner packet is 58 divided by the
packets required (fractional allowed). The overhead as a percentage number of outer packets required (fractional allowed). The overhead
of inner packet size is a constant based on the Outer MTU size. as a percentage of inner packet size is a constant based on the Outer
MTU size.
OH = 40 / Outer Payload Size / Inner Packet Size OH = 58 / Outer Payload Size / Inner Packet Size
OH % of Inner Packet Size = 100 * OH / Inner Packet Size OH % of Inner Packet Size = 100 * OH / Inner Packet Size
OH % of Inner Packet Size = 4000 / Outer Payload Size OH % of Inner Packet Size = 5800 / Outer Payload Size
Type IP-TFS IP-TFS IP-TFS Type IP-TFS IP-TFS IP-TFS
MTU 576 1500 9000 MTU 576 1500 9000
PSize 536 1460 8960 PSize 518 1442 8942
------------------------------- -------------------------------
40 7.46% 2.74% 0.45% 40 11.20% 4.02% 0.65%
576 7.46% 2.74% 0.45% 576 11.20% 4.02% 0.65%
1500 7.46% 2.74% 0.45% 1500 11.20% 4.02% 0.65%
9000 7.46% 2.74% 0.45% 9000 11.20% 4.02% 0.65%
Figure 4: IP-TFS Overhead as Percentage of Inner Packet Size Figure 4: IP-TFS Overhead as Percentage of Inner Packet Size
C.1.2. ESP with Padding Overhead C.1.2. ESP with Padding Overhead
The overhead per inner packet for constant-send-rate padded ESP The overhead per inner packet for constant-send-rate padded ESP
(i.e., traditional IPsec TFC) is 36 octets plus any padding, unless (i.e., traditional IPsec TFC) is 36 octets plus any padding, unless
fragmentation is required. fragmentation is required.
When fragmentation of the inner packet is required to fit in the When fragmentation of the inner packet is required to fit in the
outer IPsec packet, overhead is the number of outer packets required outer IPsec packet, overhead is the number of outer packets required
to carry the fragmented inner packet times both the inner IP overhead to carry the fragmented inner packet times both the inner IP overhead
(20) and the outer packet overhead (36) minus the initial inner IP (20) and the outer packet overhead (54) minus the initial inner IP
overhead plus any required tail padding in the last encapsulation overhead plus any required tail padding in the last encapsulation
packet. The required tail padding is the number of required packets packet. The required tail padding is the number of required packets
times the difference of the Outer Payload Size and the IP Overhead times the difference of the Outer Payload Size and the IP Overhead
minus the Inner Payload Size. So: minus the Inner Payload Size. So:
Inner Paylaod Size = IP Packet Size - IP Overhead Inner Paylaod Size = IP Packet Size - IP Overhead
Outer Payload Size = MTU - IPsec Overhead Outer Payload Size = MTU - IPsec Overhead
Inner Payload Size Inner Payload Size
NF0 = ---------------------------------- NF0 = ----------------------------------
skipping to change at page 26, line 12 skipping to change at page 27, line 32
OH = NF * (IPsec Overhead + Outer Payload Size) OH = NF * (IPsec Overhead + Outer Payload Size)
- Inner Packet Size - Inner Packet Size
C.2. Overhead Comparison C.2. Overhead Comparison
The following tables collect the overhead values for some common L3 The following tables collect the overhead values for some common L3
MTU sizes in order to compare them. The first table is the number of MTU sizes in order to compare them. The first table is the number of
octets of overhead for a given L3 MTU sized packet. The second table octets of overhead for a given L3 MTU sized packet. The second table
is the percentage of overhead in the same MTU sized packet. is the percentage of overhead in the same MTU sized packet.
XXX rerun these.
Type ESP+Pad ESP+Pad ESP+Pad IP-TFS IP-TFS IP-TFS Type ESP+Pad ESP+Pad ESP+Pad IP-TFS IP-TFS IP-TFS
L3 MTU 576 1500 9000 576 1500 9000 L3 MTU 576 1500 9000 576 1500 9000
PSize 540 1464 8964 536 1460 8960 PSize 522 1446 8946 518 1442 8942
----------------------------------------------------------- -----------------------------------------------------------
40 500 1424 8924 3.0 1.1 0.2 40 482 1406 8906 4.5 1.6 0.3
128 412 1336 8836 9.6 3.5 0.6 128 394 1318 8818 14.3 5.1 0.8
256 284 1208 8708 19.1 7.0 1.1 256 266 1190 8690 28.7 10.3 1.7
536 4 928 8428 40.0 14.7 2.4 518 4 928 8428 58.0 20.8 3.4
576 576 888 8388 43.0 15.8 2.6 576 576 870 8370 64.5 23.2 3.7
1460 268 4 7504 109.0 40.0 6.5 1442 286 4 7504 161.5 58.0 9.4
1500 228 1500 7464 111.9 41.1 6.7 1500 228 1500 7446 168.0 60.3 9.7
8960 1408 1540 4 668.7 245.5 40.0 8942 1426 1558 4 1001.2 359.7 58.0
9000 1368 1500 9000 671.6 246.6 40.2 9000 1368 1500 9000 1007.7 362.0 58.4
Figure 5: Overhead comparison in octets Figure 5: Overhead comparison in octets
Type ESP+Pad ESP+Pad ESP+Pad IP-TFS IP-TFS IP-TFS Type ESP+Pad ESP+Pad ESP+Pad IP-TFS IP-TFS IP-TFS
MTU 576 1500 9000 576 1500 9000 MTU 576 1500 9000 576 1500 9000
PSize 540 1464 8964 536 1460 8960 PSize 522 1446 8946 518 1442 8942
----------------------------------------------------------- -----------------------------------------------------------
40 1250.0% 3560.0% 22310.0% 7.46% 2.74% 0.45% 40 1205.0% 3515.0% 22265.0% 11.20% 4.02% 0.65%
128 321.9% 1043.8% 6903.1% 7.46% 2.74% 0.45% 128 307.8% 1029.7% 6889.1% 11.20% 4.02% 0.65%
256 110.9% 471.9% 3401.6% 7.46% 2.74% 0.45% 256 103.9% 464.8% 3394.5% 11.20% 4.02% 0.65%
536 0.7% 173.1% 1572.4% 7.46% 2.74% 0.45% 518 0.8% 179.2% 1627.0% 11.20% 4.02% 0.65%
576 100.0% 154.2% 1456.2% 7.46% 2.74% 0.45% 576 100.0% 151.0% 1453.1% 11.20% 4.02% 0.65%
1460 18.4% 0.3% 514.0% 7.46% 2.74% 0.45% 1442 19.8% 0.3% 520.4% 11.20% 4.02% 0.65%
1500 15.2% 100.0% 497.6% 7.46% 2.74% 0.45% 1500 15.2% 100.0% 496.4% 11.20% 4.02% 0.65%
8960 15.7% 17.2% 0.0% 7.46% 2.74% 0.45% 8942 15.9% 17.4% 0.0% 11.20% 4.02% 0.65%
9000 15.2% 16.7% 100.0% 7.46% 2.74% 0.45% 9000 15.2% 16.7% 100.0% 11.20% 4.02% 0.65%
Figure 6: Overhead as Percentage of Inner Packet Size Figure 6: Overhead as Percentage of Inner Packet Size
C.3. Comparing Available Bandwidth C.3. Comparing Available Bandwidth
Another way to compare the two solutions is to look at the amount of Another way to compare the two solutions is to look at the amount of
available bandwidth each solution provides. The following sections available bandwidth each solution provides. The following sections
consider and compare the percentage of available bandwidth. For the consider and compare the percentage of available bandwidth. For the
sake of providing a well understood baseline normal (unencrypted) sake of providing a well understood baseline normal (unencrypted)
Ethernet as well as normal ESP values are included. Ethernet as well as normal ESP values are included.
skipping to change at page 27, line 15 skipping to change at page 28, line 39
C.3.1. Ethernet C.3.1. Ethernet
In order to calculate the available bandwidth the per packet overhead In order to calculate the available bandwidth the per packet overhead
is calculated first. The total overhead of Ethernet is 14+4 octets is calculated first. The total overhead of Ethernet is 14+4 octets
of header and CRC plus and additional 20 octets of framing (preamble, of header and CRC plus and additional 20 octets of framing (preamble,
start, and inter-packet gap) for a total of 38 octets. Additionally start, and inter-packet gap) for a total of 38 octets. Additionally
the minimum payload is 46 octets. the minimum payload is 46 octets.
Size E + P E + P E + P IPTFS IPTFS IPTFS Enet ESP Size E + P E + P E + P IPTFS IPTFS IPTFS Enet ESP
MTU 590 1514 9014 590 1514 9014 any any MTU 590 1514 9014 590 1514 9014 any any
OH 74 74 74 78 78 78 38 74 OH 92 92 92 96 96 96 38 74
------------------------------------------------------------ ------------------------------------------------------------
40 614 1538 9038 45 42 40 84 114 40 614 1538 9038 47 42 40 84 114
128 614 1538 9038 146 134 129 166 202 128 614 1538 9038 151 136 129 166 202
256 614 1538 9038 293 269 258 294 330 256 614 1538 9038 303 273 258 294 330
536 614 1538 9038 614 564 540 574 610 518 614 1538 9038 614 552 523 574 610
576 1228 1538 9038 659 606 581 614 650 576 1228 1538 9038 682 614 582 614 650
1460 1842 1538 9038 1672 1538 1472 1498 1534 1442 1842 1538 9038 1709 1538 1457 1498 1534
1500 1842 3076 9038 1718 1580 1513 1538 1574 1500 1842 3076 9038 1777 1599 1516 1538 1574
8960 11052 10766 9038 10263 9438 9038 8998 9034 8942 11052 10766 9038 10599 9537 9038 8998 9034
9000 11052 10766 18076 10309 9480 9078 9038 9074 9000 11052 10766 18076 10667 9599 9096 9038 9074
Figure 7: L2 Octets Per Packet Figure 7: L2 Octets Per Packet
Size E + P E + P E + P IPTFS IPTFS IPTFS Enet ESP Size E + P E + P E + P IPTFS IPTFS IPTFS Enet ESP
MTU 590 1514 9014 590 1514 9014 any any MTU 590 1514 9014 590 1514 9014 any any
OH 74 74 74 78 78 78 38 74 OH 92 92 92 96 96 96 38 74
-------------------------------------------------------------- --------------------------------------------------------------
40 2.0M 0.8M 0.1M 27.3M 29.7M 31.0M 14.9M 11.0M 40 2.0M 0.8M 0.1M 26.4M 29.3M 30.9M 14.9M 11.0M
128 2.0M 0.8M 0.1M 8.5M 9.3M 9.7M 7.5M 6.2M 128 2.0M 0.8M 0.1M 8.2M 9.2M 9.7M 7.5M 6.2M
256 2.0M 0.8M 0.1M 4.3M 4.6M 4.8M 4.3M 3.8M 256 2.0M 0.8M 0.1M 4.1M 4.6M 4.8M 4.3M 3.8M
536 2.0M 0.8M 0.1M 2.0M 2.2M 2.3M 2.2M 2.0M 518 2.0M 0.8M 0.1M 2.0M 2.3M 2.4M 2.2M 2.1M
576 1.0M 0.8M 0.1M 1.9M 2.1M 2.2M 2.0M 1.9M 576 1.0M 0.8M 0.1M 1.8M 2.0M 2.1M 2.0M 1.9M
1460 678K 812K 138K 747K 812K 848K 834K 814K 1442 678K 812K 138K 731K 812K 857K 844K 824K
1500 678K 406K 138K 727K 791K 826K 812K 794K 1500 678K 406K 138K 703K 781K 824K 812K 794K
8960 113K 116K 138K 121K 132K 138K 138K 138K 8942 113K 116K 138K 117K 131K 138K 139K 138K
9000 113K 116K 69K 121K 131K 137K 138K 137K 9000 113K 116K 69K 117K 130K 137K 138K 137K
Figure 8: Packets Per Second on 10G Ethernet Figure 8: Packets Per Second on 10G Ethernet
Size E + P E + P E + P IPTFS IPTFS IPTFS Enet ESP Size E + P E + P E + P IPTFS IPTFS IPTFS Enet ESP
590 1514 9014 590 1514 9014 any any 590 1514 9014 590 1514 9014 any any
74 74 74 78 78 78 38 74 92 92 92 96 96 96 38 74
---------------------------------------------------------------------- ----------------------------------------------------------------------
40 6.51% 2.60% 0.44% 87.30% 94.93% 99.14% 47.62% 35.09% 40 6.51% 2.60% 0.44% 84.36% 93.76% 98.94% 47.62% 35.09%
128 20.85% 8.32% 1.42% 87.30% 94.93% 99.14% 77.11% 63.37% 128 20.85% 8.32% 1.42% 84.36% 93.76% 98.94% 77.11% 63.37%
256 41.69% 16.64% 2.83% 87.30% 94.93% 99.14% 87.07% 77.58% 256 41.69% 16.64% 2.83% 84.36% 93.76% 98.94% 87.07% 77.58%
536 87.30% 34.85% 5.93% 87.30% 94.93% 99.14% 93.38% 87.87% 518 84.36% 33.68% 5.73% 84.36% 93.76% 98.94% 93.17% 87.50%
576 46.91% 37.45% 6.37% 87.30% 94.93% 99.14% 93.81% 88.62% 576 46.91% 37.45% 6.37% 84.36% 93.76% 98.94% 93.81% 88.62%
1460 79.26% 94.93% 16.15% 87.30% 94.93% 99.14% 97.46% 95.18% 1442 78.28% 93.76% 15.95% 84.36% 93.76% 98.94% 97.43% 95.12%
1500 81.43% 48.76% 16.60% 87.30% 94.93% 99.14% 97.53% 95.30% 1500 81.43% 48.76% 16.60% 84.36% 93.76% 98.94% 97.53% 95.30%
8960 81.07% 83.22% 99.14% 87.30% 94.93% 99.14% 99.58% 99.18% 8942 80.91% 83.06% 98.94% 84.36% 93.76% 98.94% 99.58% 99.18%
9000 81.43% 83.60% 49.79% 87.30% 94.93% 99.14% 99.58% 99.18% 9000 81.43% 83.60% 49.79% 84.36% 93.76% 98.94% 99.58% 99.18%
Figure 9: Percentage of Bandwidth on 10G Ethernet Figure 9: Percentage of Bandwidth on 10G Ethernet
A sometimes unexpected result of using IP-TFS (or any packet A sometimes unexpected result of using IP-TFS (or any packet
aggregating tunnel) is that, for small to medium sized packets, the aggregating tunnel) is that, for small to medium sized packets, the
available bandwidth is actually greater than native Ethernet. This available bandwidth is actually greater than native Ethernet. This
is due to the reduction in Ethernet framing overhead. This increased is due to the reduction in Ethernet framing overhead. This increased
bandwidth is paid for with an increase in latency. This latency is bandwidth is paid for with an increase in latency. This latency is
the time to send the unrelated octets in the outer tunnel frame. The the time to send the unrelated octets in the outer tunnel frame. The
following table illustrates the latency for some common values on a following table illustrates the latency for some common values on a
10G Ethernet link. The table also includes latency introduced by 10G Ethernet link. The table also includes latency introduced by
padding if using ESP with padding. padding if using ESP with padding.
ESP+Pad ESP+Pad IP-TFS IP-TFS ESP+Pad ESP+Pad IP-TFS IP-TFS
1500 9000 1500 9000 1500 9000 1500 9000
------------------------------------------ ------------------------------------------
40 1.14 us 7.14 us 1.17 us 7.17 us 40 1.12 us 7.12 us 1.17 us 7.17 us
128 1.07 us 7.07 us 1.10 us 7.10 us 128 1.05 us 7.05 us 1.10 us 7.10 us
256 0.97 us 6.97 us 1.00 us 7.00 us 256 0.95 us 6.95 us 1.00 us 7.00 us
536 0.74 us 6.74 us 0.77 us 6.77 us 518 0.74 us 6.74 us 0.79 us 6.79 us
576 0.71 us 6.71 us 0.74 us 6.74 us 576 0.70 us 6.70 us 0.74 us 6.74 us
1460 0.00 us 6.00 us 0.04 us 6.04 us 1442 0.00 us 6.00 us 0.05 us 6.05 us
1500 1.20 us 5.97 us 0.00 us 6.00 us 1500 1.20 us 5.96 us 0.00 us 6.00 us
Figure 10: Added Latency Figure 10: Added Latency
Notice that the latency values are very similar between the two Notice that the latency values are very similar between the two
solutions; however, whereas IP-TFS provides for constant high solutions; however, whereas IP-TFS provides for constant high
bandwidth, in some cases even exceeding native Ethernet, ESP with bandwidth, in some cases even exceeding native Ethernet, ESP with
padding often greatly reduces available bandwidth. padding often greatly reduces available bandwidth.
Appendix D. Acknowledgements Appendix D. Acknowledgements
We would like to thank Don Fedyk for help in reviewing and editing We would like to thank Don Fedyk for help in reviewing and editing
this work. We would also like to thank Valery Smyslov for reviews this work. We would also like to thank Sean Turner and Valery
and suggestions for improvements as well as Joseph Touch for the Smyslov for reviews and many suggestions for improvements, as well as
transport area review and suggested improvements. Joseph Touch for the transport area review and suggested
improvements.
Appendix E. Contributors Appendix E. Contributors
The following people made significant contributions to this document. The following people made significant contributions to this document.
Lou Berger Lou Berger
LabN Consulting, L.L.C. LabN Consulting, L.L.C.
Email: lberger@labn.net Email: lberger@labn.net
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