Simple Two-way Active Measurement Protocol Optional ExtensionsZTE Corp.gregimirsky@gmail.comZTE Corp.xiao.min2@zte.com.cnZTE Corporation68# Zijinghua RoadNanjingJiangsu210012P.R.China+86 18105183663guo.jun2@zte.com.cnAccedian Networkshnydell@accedian.comNokiafooter.foote@nokia.com
Transport
Network Working GroupInternet-DraftIPPMPerformance Measurement
This document describes optional extensions to Simple Two-way Active Measurement Protocol (STAMP) which enable
measurement performance metrics in addition to ones supported by the STAMP base specification.
Simple Two-way Active Measurement Protocol (STAMP) supports the use of
optional extensions that use Type-Length-Value (TLV) encoding. Such extensions are to enhance the STAMP base
functions, such as measurement of one-way and round-trip delay, latency, packet loss, as well as ability to
detect packet duplication and out-of-order delivery of the test packets. This specification provides definitions of
optional STAMP extensions, their formats, and theory of operation.
STAMP - Simple Two-way Active Measurement ProtocolDSCP - Differentiated Services Code PointECN - Explicit Congestion NotificationNTP - Network Time ProtocolPTP - Precision Time ProtocolHMAC Hashed Message Authentication CodeTLV Type-Length-ValueBITS Building Integrated Timing Supply SSU Synchronization Supply UnitGPS Global Positioning SystemGLONASS Global Orbiting Navigation Satellite SystemLORAN-C Long Range Navigation System Version CMBZ Must Be ZeroedCoS Class of Service
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED",
"MAY", and "OPTIONAL" in this document are to be interpreted as
described in BCP 14
when, and only when, they appear in all capitals, as shown here.
STAMP Session-Sender transmits test packets to STAMP Session-Reflector. STAMP Session-Reflector
receives Session-Sender's packet and acts according to the configuration and optional control information
communicated in the Session-Sender's test packet. STAMP defines two different test packet formats, one for
packets transmitted by the STAMP-Session-Sender and one for packets
transmitted by the STAMP-Session-Reflector. STAMP supports two modes:
unauthenticated and authenticated. Unauthenticated STAMP test packets
are compatible on the wire with unauthenticated TWAMP-Test
packet formats.
By default, STAMP uses symmetrical packets, i.e., the size of the packet
transmitted by Session-Reflector equals the size of
the packet received by the Session-Reflector.
displays the
format of STAMP Session-Sender test packet in
unauthenticated mode that includes a TLV.
The MBZ (Must Be Zeroed) field of a test packet transmitted by
a STAMP Session-Sender MUST be 30 octets long. A STAMP
Session-Sender test packet MUST NOT use the Reflect Octets
capability defined in .
TLVs (Type-Length-Value tuples) have the two octets long Type field, two
octets long Length field that is the length of the Value field in octets.
Type values, see , less than 32768 identify
mandatory TLVs that MUST be supported by an implementation.
Type values greater than or equal to 32768
identify optional TLVs that SHOULD be ignored if the
implementation does not understand or support them.
If a Type value for TLV or sub-TLV is in the range for Vendor
Private Use, the Length MUST be at least 4, and the first four octets
MUST be that vendor's the Structure of
Management Information (SMI) Private Enterprise Number, in network octet
order. The rest of the Value field is private to the vendor.
Following sections describe the use of TLVs for STAMP
that extend STAMP capability beyond its base specification.
displays the
format of STAMP Session-Reflector test packet in
unauthenticated mode that includes a TLV.
The MBZ2 field of a test packet transmitted by
a STAMP Session-Reflector MUST be 3 octets long.
A STAMP node, whether Session-Sender or Session-Reflector, receiving a test packet MUST
determine whether the packet is a base STAMP packet or includes one or more TLVs.
The node MUST compare the value in the Length field of the UDP header and
the length of the base STAMP test packet in the mode, unauthenticated or authenticated based
on the configuration of the particular STAMP test session. If the difference between the two values is
larger than the length of UDP header, then the test packet includes one or more STAMP TLVs
that immediately follow the base STAMP test packet.
where fields are defined as the following:
Extra Padding Type - TBA1 allocated by IANA Length - 2 octets long field equals length on the Extra Padding field in octets.Extra Padding - a pseudo-random sequence of numbers. The field MAY be filled with all zeroes.
The Extra Padding TLV is similar to the Packet Padding field in TWAMP-Test packet .
The in STAMP the Packet Padding field is used to ensure symmetrical size between Session-Sender and Session-Reflector
test packets. Extra Padding TLV MUST be used to create STAMP test packets of larger size.
STAMP session-sender MAY include the Location TLV to request information from the session-reflector.
The session-sender SHOULD NOT fill any information fields except for Type and Length.
The session-reflector MUST validate the Length value against the address family of the transport encapsulating
the STAMP test packet. If the value of the Length field is invalid, the session-reflector MUST zero all fields and MUST NOT return any
information to the session-sender.
The session-reflector MUST ignore all other fields of the received Location TLV.
where fields are defined as the following:
Location Type - TBA2 allocated by IANA Length - 2 octets long field equals length on the Value field in octets. Length field value MUST be 20 octets
for the IPv4 address family. For the IPv6 address family value of the Length field MUST be 44 octets. All other values are invalid.Source MAC - 6 octets 48 bits long field. The session-reflector MUST copy Source MAC of received STAMP packet into this field.Reserved A - two octets long field. MUST be zeroed on transmission and ignored on reception.Destination IP Address - IPv4 or IPv6 destination address of the received by the session-reflector STAMP packet.Source IP Address - IPv4 or IPv6 source address of the received by the session-reflector STAMP packet.Dest.port - one octet long UDP destination port number of the received STAMP packet.Src.port - one octet long UDP source port number of the received STAMP packet.Reserved B - two octets long field. MUST be zeroed on transmission and ignored on reception.
The Location TLV MAY be used to determine the last-hop addressing for STAMP
packets including source and destination IP addresses as well as the MAC address of the last-hop router.
Last-hop MAC address MAY be monitored by the Session-Sender whether there has been a path
switch on the last hop, closest to the Session-Reflector. The IP addresses and UDP port will indicate
if there is a NAT router on the path, and allows the Session-Sender to identify the IP address
of the Session-Reflector behind the NAT, detect changes in the NAT mapping that could
cause sending the STAMP packets to the wrong Session-Reflector.
STAMP session-sender MAY include the Timestamp Information TLV to request information from the session-reflector.
The session-sender SHOULD NOT fill any information fields except for Type and Length.
The session-reflector MUST validate the Length value of the STAMP test packet.
If the value of the Length field is invalid, the session-reflector MUST zero all fields and MUST NOT return any
information to the session-sender.
where fields are defined as the following:
Timestamp Information Type - TBA3 allocated by IANA Length - 2 octets long field, equals four octets.Sync Src In - one octet long field that characterizes the source of clock synchronization at the ingress of Session-Reflector.
There are several of methods to synchronize the clock, e.g., Network Time Protocol (NTP) ,
Precision Time Protocol (PTP) , Synchronization Supply Unit (SSU) or Building Integrated Timing Supply (BITS), or
Global Positioning System (GPS), Global Orbiting Navigation Satellite System (GLONASS)
and Long Range Navigation System Version C (LORAN-C).
The value is one of .Timestamp In - one octet long field that characterizes the
method by which the ingress of Session-Reflector obtained the timestamp T2. A timestamp may be obtained with hardware assist,
via software API from a local wall clock, or from a remote clock (the latter referred to as "control plane").
The value is one of .Sync Src Out - one octet long field that characterizes the source of clock synchronization at the egress of Session-Reflector.
The value is one of .Timestamp Out - one octet long field that characterizes the
method by which the egress of Session-Reflector obtained the timestamp T3.
The value is one of .
The STAMP session-sender MAY include Class of Service (CoS) TLV in the STAMP test packet.
If the CoS TLV is present in the STAMP test packet and the value of the DSCP1 field
is zero, then the STAMP session-reflector MUST copy the values of
Differentiated Services Code Point (DSCP) ECN fields
from the received STAMP test packet into
DSCP2 and ECN fields respectively of the CoS TLV of the reflected STAMP test packet. If the value of the DSCP1 field
is non-zero,
then the STAMP session-reflector MUST use DSCP1 value from the CoS TLV in the received STAMP
test packet as DSCP value of STAMP reflected test packet and MUST copy DSCP and ECN values of the received STAMP test packet into
DSCP2 and ECN fields of Class of Service TLV in the STAMP reflected a packet. The Session-Sender, upon receiving the reflected packet,
will save the DSCP and ECN values for analysis of the CoS in the reverse direction.
where fields are defined as the following:
Class of Service Type - TBA4 allocated by IANA Length - 2 octets long field, equals four octets.DSCP1 - The Differentiated Services Code Point (DSCP) intended by the Session-Sender. To be used as the return DSCP from the Session-Reflector.DSCP2 - The received value in the DSCP field at the Session-Reflector in the forward direction.ECN - The received value in the ECN field at the Session-Reflector in the forward direction.Reserved - 18 bits long field, must be zeroed in transmission and ignored on receipt.
A STAMP Session-Sender that includes the CoS TLV sets the value of the DSCP1 field and zeroes the value
of the DSCP2 field. A STAMP Session-Reflector that received the test packet with the CoS TLV MUST include
the CoS TLV in the reflected test packet. Also, the Session-Reflector MUST copy
the value of the DSCP field of the IP header of the received STAMP test packet into the DSCP2 field in
the reflected test packet. And, at last, the Session-Reflector MUST set the value of the DSCP field in the IP header of
the reflected test packet equal to the value of the DSCP1 field of the test packet it has received.
Re-mapping of CoS in some use cases, for example, in mobile backhaul networks is used to provide multiple services,
i.e., 2G, 3G, LTE, over the same network. But if it is misconfigured, then it is often difficult to diagnose the root cause of
the problem that is viewed as an excessive packet drop of higher level service while packet drop for lower
service packets is at a normal level. Using CoS TLV in STAMP test helps to troubleshoot the existing problem and also
verify whether DiffServ policies are processing CoS as required by the configuration.
The Direct Measurement TLV enables collection of "in profile" IP packets that had been transmitted and received
by the Session-Sender and Session-Reflector respectfully. The definition of "in-profile packet" is outside the
scope of this document.
where fields are defined as the following:
Direct Measurement Type - TBA5 allocated by IANA Length - 2 octets long field equals length on the Value field in octets. Length field value MUST be 12 octets.Session-Sender Tx counter (S_TxC) is four octets long field.Session-Reflector Rx counter (R_RxC) is four octets long field. MUST be zeroed by the Session-Sender and filled by the Session-Reflector.Session-Reflector Tx counter (R_TxC) is four octets long field. MUST be zeroed by the Session-Sender and filled by the Session-Reflector.
IANA is requested to create the STAMP TLV Type registry.
All code points in the range 1 through 32759 in this registry shall be allocated
according to the "IETF Review" procedure as specified in .
Code points in the range
32760 through 65279 in this registry shall be allocated according to the "First Come First Served" procedure as
specified in .
Remaining code points are allocated according to :
ValueDescriptionReference0ReservedThis document1- 32767Mandatory TLV, unassignedIETF Review32768 - 65279Optional TLV, unassignedFirst Come First Served65280 - 65519ExperimentalThis document65520 - 65534Private UseThis document65535ReservedThis document This document defines the following new values in STAMP TLV Type registry:ValueDescriptionReferenceTBA1Extra PaddingThis documentTBA2LocationThis documentTBA3Timestamp InformationThis documentTBA4Class of ServiceThis documentTBA5Direct MeasurementThis document
IANA is requested to create Synchronization Source sub-registry as part of STAMP TLV Type registry.
All code points in the range 1 through 127 in this registry shall be allocated
according to the "IETF Review" procedure as specified in .
Code points in the range
128 through 239 in this registry shall be allocated according to the "First Come First Served" procedure as
specified in .
Remaining code points are allocated according to :
ValueDescriptionReference0ReservedThis document1- 127UnassignedIETF Review128 - 239UnassignedFirst Come First Served240 - 249ExperimentalThis document250 - 254Private UseThis document255ReservedThis document This document defines the following new values in Synchronization Source sub-registry:ValueDescriptionReference1NTPThis document2PTPThis document3SSU/BITSThis document4GPS/GLONASS/LORAN-CThis document5Local free-runningThis document
IANA is requested to create Timestamping Method sub-registry as part of STAMP TLV Type registry.
All code points in the range 1 through 127 in this registry shall be allocated
according to the "IETF Review" procedure as specified in .
Code points in the range
128 through 239 in this registry shall be allocated according to the "First Come First Served" procedure as
specified in .
Remaining code points are allocated according to :
ValueDescriptionReference0ReservedThis document1- 127UnassignedIETF Review128 - 239UnassignedFirst Come First Served240 - 249ExperimentalThis document250 - 254Private UseThis document255ReservedThis document This document defines the following new values in Timestamping Methods sub-registry:ValueDescriptionReference1HW assistThis document2SW localThis document3Control planeThis document
Use of HMAC in authenticated mode may be used to simultaneously verify both the data integrity and the authentication
of the STAMP test packets.
Authors much appreciate the thorough review and thoughful comments received from Tianran Zhou.
Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems