< draft-ietf-ipsecme-iptfs-07.txt   draft-ietf-ipsecme-iptfs-08.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 February 22, 2021 Intended status: Standards Track March 30, 2021
Expires: August 26, 2021 Expires: October 1, 2021
IP-TFS: IP Traffic Flow Security Using Aggregation and Fragmentation IP-TFS: Aggregation and Fragmentation Mode for ESP and its Use for IP
draft-ietf-ipsecme-iptfs-07 Traffic Flow Security
draft-ietf-ipsecme-iptfs-08
Abstract Abstract
This document describes a mechanism to enhance IPsec traffic flow This document describes a mechanism for aggregation and fragmentation
security (IP-TFS) by adding Traffic Flow Confidentiality (TFC) to of IP packets when they are being encapsulated in ESP payload. This
encrypted IP encapsulated traffic. TFC is provided by obscuring the new payload type can be used for various purposes such as decreasing
size and frequency of IP traffic using a fixed-sized, constant-send- encapsulation overhead for small IP packets; however, the focus in
rate IPsec tunnel. The solution allows for congestion control as this document is to enhance IPsec traffic flow security (IP-TFS) by
well as non-constant send-rate usage. The mechanisms defined in this adding Traffic Flow Confidentiality (TFC) to encrypted IP
document are generic with the intent of allowing for non-TFS uses, encapsulated traffic. TFC is provided by obscuring the size and
but such uses are outside the scope of this document. frequency of IP traffic using a fixed-sized, constant-send-rate IPsec
tunnel. The solution allows for congestion control as well as non-
constant send-rate usage.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on August 26, 2021. This Internet-Draft will expire on October 1, 2021.
Copyright Notice Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology & Concepts . . . . . . . . . . . . . . . . . 4 1.1. Terminology & Concepts . . . . . . . . . . . . . . . . . 4
2. The IP-TFS Tunnel . . . . . . . . . . . . . . . . . . . . . . 4 2. The AGGFRAG 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. End Padding . . . . . . . . . . . . . . . . . . . . . 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 . . . . . . . . . . . . . . . . . . . 10 2.4. Modes of Operation . . . . . . . . . . . . . . . . . . . 10
2.4.1. Non-Congestion Controlled Mode . . . . . . . . . . . 10 2.4.1. Non-Congestion Controlled Mode . . . . . . . . . . . 10
2.4.2. Congestion Controlled Mode . . . . . . . . . . . . . 10 2.4.2. Congestion Controlled Mode . . . . . . . . . . . . . 10
2.5. Summary of Receiver Processing . . . . . . . . . . . . . 12 2.5. Summary of Receiver Processing . . . . . . . . . . . . . 12
3. Congestion Information . . . . . . . . . . . . . . . . . . . 12 3. Congestion Information . . . . . . . . . . . . . . . . . . . 12
3.1. ECN Support . . . . . . . . . . . . . . . . . . . . . . . 13 3.1. ECN Support . . . . . . . . . . . . . . . . . . . . . . . 13
4. Configuration . . . . . . . . . . . . . . . . . . . . . . . . 14 4. Configuration of AGGFRAG Tunnels for IP-TFS . . . . . . . . . 14
4.1. Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . 14 4.1. Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . 14
4.2. Fixed Packet Size . . . . . . . . . . . . . . . . . . . . 14 4.2. Fixed Packet Size . . . . . . . . . . . . . . . . . . . . 14
4.3. Congestion Control . . . . . . . . . . . . . . . . . . . 14 4.3. Congestion Control . . . . . . . . . . . . . . . . . . . 14
5. IKEv2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5. IKEv2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.1. USE_AGGFRAG Notification Message . . . . . . . . . . . . 14 5.1. USE_AGGFRAG Notification Message . . . . . . . . . . . . 14
6. Packet and Data Formats . . . . . . . . . . . . . . . . . . . 15 6. Packet and Data Formats . . . . . . . . . . . . . . . . . . . 15
6.1. AGGFRAG_PAYLOAD Payload . . . . . . . . . . . . . . . . . 15 6.1. AGGFRAG_PAYLOAD Payload . . . . . . . . . . . . . . . . . 15
6.1.1. Non-Congestion Control AGGFRAG_PAYLOAD Payload Format 16 6.1.1. Non-Congestion Control AGGFRAG_PAYLOAD Payload Format 16
6.1.2. Congestion Control AGGFRAG_PAYLOAD Payload Format . . 16 6.1.2. Congestion Control AGGFRAG_PAYLOAD Payload Format . . 16
6.1.3. Data Blocks . . . . . . . . . . . . . . . . . . . . . 18 6.1.3. Data Blocks . . . . . . . . . . . . . . . . . . . . . 18
skipping to change at page 3, line 27 skipping to change at page 3, line 30
obscuring the data with encryption [RFC4303], the traffic pattern obscuring the data with encryption [RFC4303], the traffic pattern
itself exposes information due to variations in its shape and timing itself exposes information due to variations in its shape and timing
([RFC8546], [AppCrypt]). Hiding the size and frequency of traffic is ([RFC8546], [AppCrypt]). Hiding the size and frequency of traffic is
referred to as Traffic Flow Confidentiality (TFC) per [RFC4303]. referred to as Traffic Flow 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 (IP Traffic Flow Security) solution provides for full TFC This document defines an aggregation and fragmentation (AGGFRAG) mode
without the aforementioned bandwidth limitation. This is for ESP, and its use for IP Traffic Flow Security (IP-TFS). This
accomplished by using a constant-send-rate IPsec [RFC4303] tunnel solution provides for full TFC without the aforementioned bandwidth
with fixed-sized encapsulating packets; however, these fixed-sized limitation. This is accomplished by using a constant-send-rate IPsec
packets can contain partial, whole or multiple IP packets to maximize [RFC4303] tunnel with fixed-sized encapsulating packets; however,
the bandwidth of the tunnel. A non-constant send-rate is allowed, these fixed-sized packets can contain partial, whole or multiple IP
but the confidentiality properties of its use are outside the scope packets to maximize the bandwidth of the tunnel. A non-constant
of this document. send-rate is allowed, 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 operating fairly within congested Additionally, IP-TFS provides for operating fairly within congested
networks [RFC2914]. This is important for when the IP-TFS user is networks [RFC2914]. This is important for when the IP-TFS user is
not in full control of the domain through which the IP-TFS tunnel not in full control of the domain through which the IP-TFS tunnel
path flows. path flows.
The mechanisms defined in this document are generic with the intent The mechanisms, such as the AGGFRAG mode, defined in this document
of allowing for non-TFS uses, but such uses are outside the scope of are generic with the intent of allowing for non-TFS uses, but such
this document. 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 BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
This document assumes familiarity with IP security concepts including This document assumes familiarity with IP security concepts including
TFC as described in [RFC4301]. TFC as described in [RFC4301].
2. The IP-TFS Tunnel 2. The AGGFRAG Tunnel
As mentioned in Section 1 IP-TFS utilizes an IPsec [RFC4303] tunnel As mentioned in Section 1, AGGFRAG mode utilizes an IPsec [RFC4303]
as its transport. To provide for full TFC, fixed-sized encapsulating tunnel as its transport. For the purpose of IP-TFS, fixed-sized
packets are sent at a constant rate on the tunnel. encapsulating packets are sent at a constant rate on the AGGFRAG
tunnel.
The primary input to the tunnel algorithm is the requested bandwidth The primary input to the tunnel algorithm is the requested bandwidth
to be used by the tunnel. Two values are then required to provide to be used by the tunnel. Two values are then required to provide
for this bandwidth use, the fixed size of the encapsulating packets, for this bandwidth use, the fixed size of the encapsulating packets,
and rate at which to send them. and rate at which to send them.
The fixed packet size MAY either be specified manually or be The fixed packet size MAY either be specified manually or be
determined through other methods such as the Packetization Layer MTU determined through other methods such as the Packetization Layer 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. For PLMTUD, congestion 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 control payloads can be used as in-band probes (see Section 6.1.2 and
[RFC8899]). [RFC8899]).
Given the encapsulating packet size and the requested bandwidth to be Given the encapsulating packet size and the requested bandwidth to be
used, 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 to be used divided by the packet send rate is the requested bandwidth to be used divided by the
size of the encapsulating packet. size of the encapsulating packet.
The egress (receiving) side of the IP-TFS tunnel MUST allow for and The egress (receiving) side of the AGGFRAG tunnel MUST allow for and
expect the ingress (sending) side of the IP-TFS tunnel to vary the expect the ingress (sending) side of the AGGFRAG tunnel to vary the
size and rate of sent encapsulating packets, unless constrained by size and rate of sent encapsulating packets, unless constrained by
other policy. 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 by introducing
an AGGFRAG mode for ESP.
IP-TFS aggregates as well as fragments the inner IP traffic flow into AGGFRAG mode aggregates as well as fragments the inner IP traffic
fixed-sized encapsulating IPsec tunnel packets. Padding is only flow into encapsulating IPsec tunnel packets. For IP-TFS, the IPsec
added to the the tunnel packets if there is no data available to be encapsulating tunnel packets are a fixed size. Padding is only added
sent at the time of tunnel packet transmission, or if fragmentation to the the tunnel packets if there is no data available to be sent at
has been disabled by the receiver. the time of tunnel packet transmission, or if fragmentation 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]) Next Header field value AGGFRAG_PAYLOAD (Section 6.1). [RFC4303]) Next Header field value AGGFRAG_PAYLOAD (Section 6.1).
Other non-IP-TFS uses of this aggregation and fragmentation Other non-IP-TFS uses of this AGGFRAG mode have been suggested, such
encapsulation have been identified, such as increased performance as increased performance through packet aggregation, as well as
through packet aggregation, as well as handling MTU issues using handling MTU issues using fragmentation. These uses are not defined
fragmentation. These uses are not defined here, but are also not 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 comprised of a 4 or 24 octet header followed by either a partial
datablock, a full datablock, or multiple partial or full datablocks. datablock, a full datablock, or multiple partial or full datablocks.
The following diagram illustrates this payload within the ESP packet. The following diagram illustrates this payload within the ESP packet.
See Section 6.1 for the exact formats of the AGGFRAG_PAYLOAD payload. See Section 6.1 for the exact formats of the AGGFRAG_PAYLOAD payload.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
skipping to change at page 5, line 44 skipping to change at page 5, line 44
+---------------------------------------------------------------+ +---------------------------------------------------------------+
: [Optional Congestion Info] : : [Optional Congestion Info] :
+---------------------------------------------------------------+ +---------------------------------------------------------------+
| DataBlocks ... ~ | DataBlocks ... ~
~ ~ ~ ~
~ | ~ |
+---------------------------------------------------------------| +---------------------------------------------------------------|
. ESP Trailer... . . ESP Trailer... .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 1: Layout of an IP-TFS IPsec Packet Figure 1: Layout of an AGGFRAG mode 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 the data block that is still being re-assembled. belongs to the data block that is still being re-assembled.
If the "BlockOffset" points past the end of the "DataBlocks" data If the "BlockOffset" points past the end of the "DataBlocks" data
then the next data block occurs in a subsequent encapsulating packet. then the next data block occurs in a subsequent 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 AGGFRAG mode 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 a DataBlock 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
skipping to change at page 7, line 29 skipping to change at page 7, line 29
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, note that as IP-TFS is reordering seen in arriving packets. Finally, note that as IP-TFS 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), or non-IP-TFS uses of AGGFRAG mode, can of
well. course use timers to drop packets as 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 document so the Gaps in the sequence numbers will not work for this document so the
sequence number stream MUST increase monotonically by 1 for each sequence number stream MUST increase monotonically by 1 for each
subsequent packet. subsequent packet.
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 can be reduced to the smaller of the two
two window sizes. This is because packets outside of the smaller window sizes. This is because packets outside of the smaller window
window but inside the larger would still be dropped by the mechanism but inside the larger would still be dropped by the mechanism with
with the smaller window size. 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), senders MUST NOT send initial fragments of an re-keying a child SA), senders MUST NOT send initial fragments of an
inner packet using one SA and subsequent fragments in a different SA. inner packet using one SA and subsequent fragments in 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, a sender MAY When the tunnel bandwidth is not being fully utilized, a sender MAY
pad-out the current encapsulating packet in order to deliver an inner pad-out the current encapsulating packet in order to deliver an inner
packet un-fragmented in the following outer packet. The benefit packet un-fragmented in the following outer packet. The benefit
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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. Senders implementing either of the above throughput of a tunnel. Senders implementing either of the 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
To support reporting of congestion control information (described To support reporting of congestion control information (described
later) on a non-AGGFRAG_PAYLOAD enabled SA, IP-TFS allows for the later) using a non-AGGFRAG_PAYLOAD enabled SA, it is allowed to send
sending of an AGGFRAG_PAYLOAD payload with no data blocks (i.e., the an AGGFRAG_PAYLOAD payload with no data blocks (i.e., the ESP payload
ESP payload length is equal to the AGGFRAG_PAYLOAD header length). length is equal to the AGGFRAG_PAYLOAD header length). This special
This special payload is called an empty payload. payload is called an empty payload.
Currently this situation is only applicable in non-IKEv2 use cases. 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],
TFS may and often will be encapsulating more than one IP packet per AGGFRAG mode may and often will be encapsulating more than one IP
ESP packet. To deal with this, these mappings are restricted packet per ESP packet. To deal with this, these mappings are
further. restricted further.
2.2.5.1. DF bit 2.2.5.1. DF bit
IP-TFS never maps the inner DF bit as it is unrelated to the IP-TFS AGGFRAG mode never maps the inner DF bit as it is unrelated to the
tunnel functionality; IP-TFS never needs to IP fragment the inner AGGFRAG tunnel functionality; AGGFRAG mode never needs to IP fragment
packets and the inner packets will not affect the fragmentation of the inner packets and the inner packets will not affect the
the outer encapsulation packets. fragmentation of the outer encapsulation packets.
2.2.5.2. ECN value 2.2.5.2. ECN value
The ECN value need not be mapped as any congestion related to the 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 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 inner traffic flow. The sender MAY still set the ECN value of inner
packets based on the normal ECN specification [RFC3168]. packets based on the normal ECN specification [RFC3168].
2.2.5.3. DS field 2.2.5.3. DS field
By default the DS field SHOULD NOT be copied, although a sender MAY By default the DS field SHOULD NOT be copied, although a sender MAY
choose to allow for configuration to override this behavior. A choose to allow for configuration to override this behavior. A
sender SHOULD also allow the DS value to be set by configuration. 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) are handled the same as with non IP-TFS IPsec to tunnel traffic) are handled the same as with non-AGGFRAG 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
TFS tunnel as all IP packet sizes are properly transmitted without AGGFRAG tunnel as all IP packet sizes are properly transmitted
requiring IP fragmentation prior to tunnel ingress. That said, a without requiring IP fragmentation prior to tunnel ingress. That
sender MAY allow for explicitly configuring an MTU for the tunnel. said, a sender MAY allow for explicitly configuring an MTU for the
tunnel.
If IP-TFS fragmentation has been disabled, then the tunnel's EMTU and If fragmentation has been disabled on the AGGFRAG tunnel, then the
behaviors are the same as normal IPsec tunnels [RFC4301]. tunnel's EMTU and behaviors are the same as normal IPsec tunnels
[RFC4301].
2.3. Exclusive SA Use 2.3. Exclusive SA Use
This document does not specify mixed use of an AGGFRAG_PAYLOAD This document does not specify mixed use of an AGGFRAG_PAYLOAD
enabled SA. A sender MUST only send AGGFRAG_PAYLOAD payloads over an enabled SA. A sender MUST only send AGGFRAG_PAYLOAD payloads over an
SA configured for AGGFRAG_PAYLOAD use. SA configured for AGGFRAG mode.
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, AGGFRAG 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 AGGFRAG tunnels, one in either direction.
An IP-TFS tunnel can operate in 2 modes, a non-congestion controlled An AGGFRAG tunnel used for IP-TFS can operate in 2 modes, a non-
mode and congestion controlled mode. congestion controlled 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 over an AGGFRAG tunnel at a constant rate. The packet send
not automatically adjusted regardless of any network congestion rate is constant and is not automatically adjusted regardless of any
(e.g., packet loss). network congestion (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.
skipping to change at page 11, line 20 skipping to change at page 11, line 20
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. Not 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 its 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 its IP-TFS payload header if sending on an IP-TFS information in its AGGFRAG 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 choosing a congestion control algorithm (or a selection of When choosing a congestion control algorithm (or a selection of
algorithms) note that IP-TFS is not providing for reliable delivery algorithms) note that IP-TFS is not providing for reliable delivery
of IP traffic, and so per packet ACKs are not required and are not of IP traffic, and so per packet ACKs are not required and are not
provided. provided.
It is 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 AGGFRAG 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 2.5. Summary of Receiver Processing
An IP-TFS receiver has a few tasks to perform. An AGGFRAG enabled SA receiver has a few tasks to perform.
The receiver first reorders, possibly out-of-order ESP packets The receiver first reorders, possibly out-of-order ESP packets
received on an SA into in-sequence-order AGGFRAG_PAYLOAD payloads received on an SA into in-sequence-order AGGFRAG_PAYLOAD payloads
(Section 2.2.3). If congestion control is enabled, the receiver (Section 2.2.3). If congestion control is enabled, the receiver
considers a packet lost when it's sequence number is abandoned (e.g., 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 pushed out of the re-ordering window, or timed-out) by the reordering
algorithm. algorithm.
Additionally, if congestion control is enabled, the receiver sends Additionally, if congestion control is enabled, the receiver sends
congestion control data (Section 6.1.2) back to the sender as congestion control data (Section 6.1.2) back to the sender as
skipping to change at page 13, line 4 skipping to change at page 13, line 4
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. same "TVal" MUST NOT update the recorded time.
When the receiver sends its CC header it places this latest recorded When the receiver sends its CC header it places this latest recorded
"TVal" in the "TEcho" header field, along with 2 delay values, "Echo "TVal" in the "TEcho" header field, along with 2 delay values, "Echo
Delay" and "Transmit Delay". The "Echo Delay" value is the time Delay" and "Transmit Delay". The "Echo Delay" value is the time
delta from the recorded arrival time of "TVal" and the current clock delta from the recorded arrival time of "TVal" and the current clock
in microseconds. The second value, "Transmit Delay", is the in microseconds. The second value, "Transmit Delay", is the
receiver's current transmission delay on the tunnel (i.e., the receiver's current transmission delay on the tunnel (i.e., the
average time between sending packets on its half of the IP-TFS average time between sending packets on its half of the AGGFRAG
tunnel). tunnel).
When the sender receives back its "TVal" in the "TEcho" header field When the sender receives back its "TVal" in the "TEcho" header field
it calculates 2 RTT estimates. The first is the actual delay found it calculates 2 RTT estimates. The first is the actual delay found
by subtracting the "TEcho" value from its current clock and then 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 its half of the IP-TFS tunnel). The larger of these 2 RTT packets on its half of the AGGFRAG tunnel). The larger of these 2
estimates SHOULD be used as the "RTT" value. RTT estimates SHOULD be used as the "RTT" value.
The two RTT estimates are required to handle different combinations The two RTT estimates are required to handle different combinations
of faster or slower tunnel packet paths with faster or slower fixed of faster or slower tunnel packet paths with faster or slower fixed
tunnel rates. Choosing the larger of the two values guarantees that tunnel rates. Choosing the larger of the two values guarantees that
the "RTT" is never considered faster than the aggregate transmission the "RTT" is never considered faster than the aggregate transmission
delay based on the IP-TFS tunnel rate (the second estimate), as well delay based on the IP-TFS send rate (the second estimate), as well as
as never being considered faster than the actual RTT along the tunnel never being considered faster than the actual RTT along the tunnel
packet path (the first estimate). 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 AGGFRAG mode supports
of the ECN bits in the encapsulating IP header [RFC3168] for use 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 (receiving) side with the Congestion Experienced (CE) at the egress (receiving) side with the Congestion Experienced (CE)
value 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 thus may constitute a covert channel. For this reason, ECN use
SHOULD NOT be enabled by default. SHOULD NOT be enabled by default.
4. Configuration 4. Configuration of AGGFRAG Tunnels for IP-TFS
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 specified configuration. All IP-TFS specific configuration should be specified
at the unidirectional tunnel ingress (sending) side. It is intended at the unidirectional tunnel ingress (sending) side. It is intended
that non-IKEv2 operation is supported, at least, with local static that non-IKEv2 operation is supported, at least, with 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
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4.3. Congestion Control 4.3. Congestion Control
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 AGGFRAG tunnels utilize ESP payloads of type
AGGFRAG_PAYLOAD. AGGFRAG_PAYLOAD.
When using IKEv2, a new "USE_AGGFRAG" Notification Message enables When using IKEv2, a new "USE_AGGFRAG" Notification Message enables
the AGGFRAG_PAYLOAD payload on a child SA pair. The method used is the AGGFRAG_PAYLOAD payload on a child SA pair. The method used is
similar to how USE_TRANSPORT_MODE is negotiated, as described in similar to how USE_TRANSPORT_MODE is negotiated, as described in
[RFC7296]. [RFC7296].
To request use of 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
skipping to change at page 15, line 33 skipping to change at page 15, line 33
6. Packet and Data Formats 6. Packet and Data Formats
The packet and data formats defined below are generic with the intent 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 allowing for non-IP-TFS uses, but such uses are outside the scope
of this document. of this document.
6.1. AGGFRAG_PAYLOAD Payload 6.1. AGGFRAG_PAYLOAD Payload
ESP Next Header value: 0x5 ESP Next Header value: 0x5
An IP-TFS payload is identified by the ESP Next Header value An AGGFRAG payload is identified by the ESP Next Header value
AGGFRAG_PAYLOAD which has the value 0x5. The value 5 was chosen to AGGFRAG_PAYLOAD which has the value 0x5. The value 5 was chosen to
not conflict with other used values. The first octet of this payload not conflict with other used values. The first octet of this payload
indicates the format of the remaining payload data. 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:
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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 TFC to IP traffic. Use of This document describes an aggregation and fragmentation mechanism
this mechanism is expected to increase the security of the traffic and it use to add TFC to IP traffic. The use described is expected
being transported. Other than the additional security afforded by to increase the security of the traffic being transported. Other
using this mechanism, IP-TFS utilizes the security protocols than the additional security afforded by using this mechanism, IP-TFS
[RFC4303] and [RFC7296] and so their security considerations apply to utilizes the security protocols [RFC4303] and [RFC7296] and so their
IP-TFS as well. security considerations apply to IP-TFS as well.
As noted in (Section 3.1) the ECN bits are not protected by IPsec and 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 thus may constitute a covert channel. For this reason, ECN use
SHOULD NOT be enabled by default. 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.
skipping to change at page 24, line 50 skipping to change at page 24, line 50
Offset: 0 Offset: 100 Offset: 2900 Offset: 1400 Offset: 0 Offset: 100 Offset: 2900 Offset: 1400
[ ESP1 (1500) ][ ESP2 (1500) ][ ESP3 (1500) ][ ESP4 (1500) ] [ ESP1 (1500) ][ ESP2 (1500) ][ ESP3 (1500) ][ ESP4 (1500) ]
[--800--][--800--][60][-240-][--4000----------------------][pad] [--800--][--800--][60][-240-][--4000----------------------][pad]
Figure 3: Inner and Outer Packet Flow Figure 3: Inner and Outer Packet Flow
The encapsulated IP packet flow (lengths include IP header and The encapsulated IP packet flow (lengths include IP header and
payload) is as follows: an 800 octet packet, an 800 octet packet, a payload) is as follows: an 800 octet packet, an 800 octet packet, a
60 octet packet, a 240 octet packet, a 4000 octet packet. 60 octet packet, a 240 octet packet, a 4000 octet packet.
The "BlockOffset" values in the 4 IP-TFS payload headers for this The "BlockOffset" values in the 4 AGGFRAG payload headers for this
packet flow would thus be: 0, 100, 2900, 1400 respectively. The packet flow would thus be: 0, 100, 2900, 1400 respectively. The
first encapsulating packet ESP1 has a zero "BlockOffset" which points first encapsulating packet ESP1 has a zero "BlockOffset" which points
at the IP data block immediately following the IP-TFS header. The at the IP data block immediately following the AGGFRAG header. The
following packet ESP2s "BlockOffset" points inward 100 octets to the following packet ESP2s "BlockOffset" points inward 100 octets to the
start of the 60 octet data block. The third encapsulating packet start of the 60 octet data block. The third encapsulating packet
ESP3 contains the middle portion of the 4000 octet data block so the ESP3 contains the middle portion of the 4000 octet data block so the
offset points past its end and into the forth encapsulating packet. offset points past its end and into the forth encapsulating packet.
The fourth packet ESP4s offset is 1400 pointing at the padding which The fourth packet ESP4s offset is 1400 pointing at the padding which
follows the completion of the continued 4000 octet packet. follows the completion of the continued 4000 octet packet.
Appendix B. A Send and Loss Event Rate Calculation Appendix B. A Send and Loss Event Rate Calculation
The current best practice indicates that congestion control SHOULD be The current best practice indicates that congestion control SHOULD be
skipping to change at page 25, line 49 skipping to change at page 25, line 49
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 For comparing overhead the overhead of ESP for both normal and
tunnel packets must be calculated, and so an algorithm for encryption AGGFRAG tunnel packets must be calculated, and so an algorithm for
and authentication must be chosen. For the data below AES-GCM-256 encryption and authentication must be chosen. For the data below
was selected. This leads to an IP+ESP overhead of 54. 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) 54 = 20 (IP) + 8 (ESPH) + 2 (ESPF) + 8 (IV) + 16 (ICV)
Additionally, for IP-TFS, non-congestion control AGGFRAG_PAYLOAD Additionally, for IP-TFS, non-congestion control AGGFRAG_PAYLOAD
headers were chosen which adds 4 octets for a total overhead of 58. 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
For comparison the overhead of IP-TFS is 58 octets per outer packet. For comparison the overhead of AGGFRAG payload is 58 octets per outer
Therefore the octet overhead per inner packet is 58 divided by the packet. Therefore the octet overhead per inner packet is 58 divided
number of outer packets required (fractional allowed). The overhead by the number of outer packets required (fractional allowed). The
as a percentage of inner packet size is a constant based on the Outer overhead as a percentage of inner packet size is a constant based on
MTU size. the Outer MTU size.
OH = 58 / 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 = 5800 / 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 518 1442 8942 PSize 518 1442 8942
------------------------------- -------------------------------
40 11.20% 4.02% 0.65% 40 11.20% 4.02% 0.65%
skipping to change at page 29, line 37 skipping to change at page 29, line 37
256 41.69% 16.64% 2.83% 84.36% 93.76% 98.94% 87.07% 77.58% 256 41.69% 16.64% 2.83% 84.36% 93.76% 98.94% 87.07% 77.58%
518 84.36% 33.68% 5.73% 84.36% 93.76% 98.94% 93.17% 87.50% 518 84.36% 33.68% 5.73% 84.36% 93.76% 98.94% 93.17% 87.50%
576 46.91% 37.45% 6.37% 84.36% 93.76% 98.94% 93.81% 88.62% 576 46.91% 37.45% 6.37% 84.36% 93.76% 98.94% 93.81% 88.62%
1442 78.28% 93.76% 15.95% 84.36% 93.76% 98.94% 97.43% 95.12% 1442 78.28% 93.76% 15.95% 84.36% 93.76% 98.94% 97.43% 95.12%
1500 81.43% 48.76% 16.60% 84.36% 93.76% 98.94% 97.53% 95.30% 1500 81.43% 48.76% 16.60% 84.36% 93.76% 98.94% 97.53% 95.30%
8942 80.91% 83.06% 98.94% 84.36% 93.76% 98.94% 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% 84.36% 93.76% 98.94% 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 an AGGFRAG tunnel (or any
aggregating tunnel) is that, for small to medium sized packets, the packet aggregating tunnel) is that, for small to medium sized
available bandwidth is actually greater than native Ethernet. This packets, the available bandwidth is actually greater than native
is due to the reduction in Ethernet framing overhead. This increased Ethernet. This is due to the reduction in Ethernet framing overhead.
bandwidth is paid for with an increase in latency. This latency is This increased bandwidth is paid for with an increase in latency.
the time to send the unrelated octets in the outer tunnel frame. The This latency is the time to send the unrelated octets in the outer
following table illustrates the latency for some common values on a tunnel frame. The following table illustrates the latency for some
10G Ethernet link. The table also includes latency introduced by common values on a 10G Ethernet link. The table also includes
padding if using ESP with padding. latency introduced by 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 1.12 us 7.12 us 1.17 us 7.17 us 40 1.12 us 7.12 us 1.17 us 7.17 us
128 1.05 us 7.05 us 1.10 us 7.10 us 128 1.05 us 7.05 us 1.10 us 7.10 us
256 0.95 us 6.95 us 1.00 us 7.00 us 256 0.95 us 6.95 us 1.00 us 7.00 us
518 0.74 us 6.74 us 0.79 us 6.79 us 518 0.74 us 6.74 us 0.79 us 6.79 us
576 0.70 us 6.70 us 0.74 us 6.74 us 576 0.70 us 6.70 us 0.74 us 6.74 us
skipping to change at page 30, line 27 skipping to change at page 30, line 27
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 Sean Turner and Valery this work. We would also like to thank Michael Richardson, Sean
Smyslov for reviews and many suggestions for improvements, as well as Turner and Valery Smyslov for reviews and many suggestions for
Joseph Touch for the transport area review and suggested improvements, as well as Joseph Touch for the transport area review
improvements. 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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