rfc9571.original   rfc9571.txt 
MPLS Working Group S. Bryant (Ed) Internet Engineering Task Force (IETF) S. Bryant, Ed.
Internet-Draft Futurewei Technologies Inc. Request for Comments: 9571 Futurewei Technologies Inc.
Intended status: Standards Track G. Swallow Category: Standards Track G. Swallow
Expires: September 6, 2021 Southend Technical Center ISSN: 2070-1721 Southend Technical Center
M. Chen M. Chen
Huawei Huawei
G. Fioccola G. Fioccola
Huawei Technologies Huawei Technologies
G. Mirsky G. Mirsky
ZTE Corp. ZTE Corp.
March 05, 2021 May 2024
RFC6374 Synonymous Flow Labels Extension of RFC 6374-Based Performance Measurement Using Synonymous
draft-ietf-mpls-rfc6374-sfl-10 Flow Labels
Abstract Abstract
RFC 6374 describes methods of making loss and delay measurements on RFC 6374 describes methods of making loss and delay measurements on
Label Switched Paths (LSPs) primarily as used in MPLS Transport Label Switched Paths (LSPs) primarily as they are used in MPLS
Profile (MPLS-TP) networks. This document describes a method of Transport Profile (MPLS-TP) networks. This document describes a
extending RFC 6374 performance measurements from flows carried over method of extending the performance measurements (specified in RFC
MPLS-TP to flows carried over generic MPLS LSPs. In particular, it 6374) from flows carried over MPLS-TP to flows carried over generic
extends the technique to allow loss and delay measurements to be made MPLS LSPs. In particular, it extends the technique to allow loss and
on multi-point to point LSPs and introduces some additional delay measurements to be made on multipoint-to-point LSPs and
techniques to allow more sophisticated measurements to be made in introduces some additional techniques to allow more sophisticated
both MPLS-TP and generic MPLS networks. measurements to be made in both MPLS-TP and generic MPLS networks.
Status of This Memo Status of This Memo
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provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on September 6, 2021. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9571.
Copyright Notice Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. in the Revised BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 4 2. Requirements Language
3. RFC6374 Packet Loss Measurement with SFL . . . . . . . . . . 4 3. Packet Loss Measurement Using SFL
4. RFC6374 Single Packet Delay Measurement . . . . . . . . . . . 4 4. Single Packet Delay Measurement Using SFL
5. Data Service Packet Delay Measurement . . . . . . . . . . . . 5 5. Data Service Packet Delay Measurement
6. Some Simplifying Rules . . . . . . . . . . . . . . . . . . . 6 6. Some Simplifying Rules
7. Multiple Packet Delay Characteristics . . . . . . . . . . . . 7 7. Multiple Packet Delay Characteristics
7.1. Method 1: Time Buckets . . . . . . . . . . . . . . . . . 7 7.1. Method 1: Time Buckets
7.2. Method 2 Classic Standard Deviation . . . . . . . . . . . 9 7.2. Method 2: Classic Standard Deviation
7.2.1. Multi-Packet Delay Measurement Message Format . . . . 10 7.2.1. Multi-packet Delay Measurement Message Format
7.3. Per Packet Delay Measurement . . . . . . . . . . . . . . 11 7.3. Per-Packet Delay Measurement
7.4. Average Delay . . . . . . . . . . . . . . . . . . . . . . 11 7.4. Average Delay
8. Sampled Measurement . . . . . . . . . . . . . . . . . . . . . 13 8. Sampled Measurement
9. Carrying RFC6374 Packets over an LSP using an SFL . . . . . . 13 9. Carrying Packets over an LSP Using an SFL
9.1. RFC6374 SFL TLV . . . . . . . . . . . . . . . . . . . . . 15 9.1. Extending RFC 6374 with SFL TLV
10. RFC6374 Combined Loss-Delay Measurement . . . . . . . . . . . 16 10. Combined Loss/Delay Measurement Using SFL
11. Privacy Considerations . . . . . . . . . . . . . . . . . . . 17 11. Privacy Considerations
12. Security Considerations . . . . . . . . . . . . . . . . . . . 17 12. Security Considerations
13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 13. IANA Considerations
13.1. Allocation of MPLS Generalized Associated Channel 13.1. Allocation of MPLS Generalized Associated Channel (G-ACh)
(G-ACh) Types . . . . . . . . . . . . . . . . . . . . . 17 Types
13.2. Allocation of MPLS Loss/Delay TLV Object . . . . . . . . 18 13.2. Allocation of MPLS Loss/Delay TLV Object
14. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18 14. References
15. Contributing Authors . . . . . . . . . . . . . . . . . . . . 18 14.1. Normative References
16. References . . . . . . . . . . . . . . . . . . . . . . . . . 18 14.2. Informative References
16.1. Normative References . . . . . . . . . . . . . . . . . . 18 Acknowledgments
16.2. Informative References . . . . . . . . . . . . . . . . . 20 Contributors
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20 Authors' Addresses
1. Introduction 1. Introduction
[RFC6374] was originally designed for use as an Operations, [RFC6374] was originally designed for use as an Operations,
Administration, and Maintenance (OAM) protocol for use with MPLS Administration, and Maintenance (OAM) protocol for use with MPLS
Transport Profile (MPLS-TP) [RFC5921] LSPs. MPLS-TP only supports Transport Profile (MPLS-TP) [RFC5921] LSPs. MPLS-TP only supports
point-to-point and point-to-multi-point LSPs. This document point-to-point and point-to-multipoint LSPs. This document describes
describes how to use RFC6374 in the generic MPLS case, and also how to use [RFC6374] in the generic MPLS case and also introduces a
introduces a number of more sophisticated measurements of number of more sophisticated measurements of applicability to both
applicability to both cases. cases.
[RFC8372] describes the requirement for introducing flow identities [RFC8372] describes the requirement for introducing flow identities
when using RFC6374 [RFC6374] packet Loss Measurements (LM). In when using packet loss measurements described in [RFC6374]. In
summary RFC6374 uses the loss-measurement (LM) packet as the packet summary, [RFC6374] describes use of the loss measurement (LM) message
accounting demarcation point. Unfortunately this gives rise to a as the packet accounting demarcation point. Unfortunately, this
number of problems that may lead to significant packet accounting gives rise to a number of problems that may lead to significant
errors in certain situations. For example: packet accounting errors in certain situations. For example:
1. Where a flow is subjected to Equal Cost Multi-Path (ECMP) 1. Where a flow is subjected to Equal-Cost Multipath (ECMP)
treatment packets can arrive out of order with respect to the LM treatment, packets can arrive out of order with respect to the LM
packet. packet.
2. Where a flow is subjected to ECMP treatment, packets can arrive 2. Where a flow is subjected to ECMP treatment, packets can arrive
at different hardware interfaces, thus requiring reception of an at different hardware interfaces, thus requiring reception of an
LM packet on one interface to trigger a packet accounting action LM packet on one interface to trigger a packet accounting action
on a different interface which may not be co-located with it. on a different interface that may not be co-located with it.
This is a difficult technical problem to address with the This is a difficult technical problem to address with the
required degree of accuracy. required degree of accuracy.
3. Even where there is no ECMP (for example on RSVP-TE, MPLS-TP LSPs 3. Even where there is no ECMP (for example, on RSVP-TE, MPLS-TP
and pseudowires(PWs)) local processing may be distributed over a LSPs, and pseudowires (PWs)), local processing may be distributed
number of processor cores, leading to synchronization problems. over a number of processor cores, leading to synchronization
problems.
4. Link aggregation techniques [RFC7190] may also lead to 4. Link aggregation techniques [RFC7190] may also lead to
synchronization issues. synchronization issues.
5. Some forwarder implementations have a long pipeline between 5. Some forwarder implementations have a long pipeline between
processing a packet and incrementing the associated counter, processing a packet and incrementing the associated counter,
again leading to synchronization difficulties. again leading to synchronization difficulties.
An approach to mitigating these synchronization issue is described in An approach to mitigating these synchronization issues is described
[RFC8321] in which packets are batched by the sender and each batch in [RFC9341] -- the packets are batched by the sender, and each batch
is marked in some way such that adjacent batches can be easily is marked in some way such that adjacent batches can be easily
recognized by the receiver. recognized by the receiver.
An additional problem arises where the LSP is a multi-point to point An additional problem arises where the LSP is a multipoint-to-point
LSP, since MPLS does not include a source address in the packet. LSP since MPLS does not include a source address in the packet.
Network management operations require the measurement of packet loss Network management operations require the measurement of packet loss
between a source and destination. It is thus necessary to introduce between a source and destination. It is thus necessary to introduce
some source specific information into the packet to identify packet some source-specific information into the packet to identify packet
batches from a specific source. batches from a specific source.
[RFC8957] describes a method of encoding per flow instructions in an [RFC8957] describes a method of encoding per-flow instructions in an
MPLS label stack using a technique called Synonymous Flow Labels MPLS label stack using a technique called Synonymous Flow Labels
(SFL) in which labels which mimic the behavior of other labels (SFLs), in which labels that mimic the behavior of other labels
provide the packet batch identifiers and enable the per batch packet provide the packet batch identifiers and enable the per-batch packet
accounting. This memo specifies how SFLs are used to perform RFC6374 accounting. This memo specifies how SFLs are used to perform packet
packet loss and RFC6374 delay measurements. loss and delay measurements as described in [RFC6374].
When the terms "performance measurement method," "Query," "packet,"
or "message" are used in this document, they refer to a performance
measurement method, Query, packet, or message as specified in
[RFC6374].
2. Requirements Language 2. Requirements Language
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
14 [RFC2119] [RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
3. RFC6374 Packet Loss Measurement with SFL 3. Packet Loss Measurement Using SFL
The data service packets of the flow being instrumented are grouped The data service packets of the flow being instrumented are grouped
into batches, and all the packets within a batch are marked with the into batches, and all the packets within a batch are marked with the
SFL [RFC8372] corresponding to that batch. The sender counts the SFL [RFC8372] corresponding to that batch. The sender counts the
number of packets in the batch. When the batch has completed and the number of packets in the batch. When the batch has completed and the
sender is confident that all of the packets in that batch will have sender is confident that all of the packets in that batch will have
been received, the sender issues an RFC6374 Query message to been received, the sender issues a Query message to determine the
determine the number actually received and hence the number of number actually received and hence the number of packets lost. The
packets lost. The RFC6374 Query message is sent using the same SFL Query message is sent using the same SFL as the corresponding batch
as the corresponding batch of data service packets. The format of of data service packets. The format of the Query and Response
the Query and Response packets is described in Section 9. packets is described in Section 9.
4. RFC6374 Single Packet Delay Measurement 4. Single Packet Delay Measurement Using SFL
RFC6374 describes how to measure the packet delay by measuring the [RFC6374] describes how to measure the packet delay by measuring the
transit time of an RFC6374 packet over an LSP. Such a packet may not transit time of a packet over an LSP. Such a packet may not need to
need to be carried over an SFL since the delay over a particular LSP be carried over an SFL since the delay over a particular LSP should
should be a function of the Traffic Class (TC) bits. be a function of the Traffic Class (TC) bits.
However, where SFLs are being used to monitor packet loss or where However, where SFLs are being used to monitor packet loss or where
label inferred scheduling is used [RFC3270] then the SFL would be label-inferred scheduling is used [RFC3270], then the SFL would be
REQUIRED to ensure that the RFC6374 packet which was being used as a REQUIRED to ensure that the packet that was being used as a proxy for
proxy for a data service packet experienced a representative delay. a data service packet experienced a representative delay. The format
The format of an RFC6374 packet carried over the LSP using an SFL is of a packet carried over the LSP using an SFL is shown in Section 9.
shown in Section 9.
5. Data Service Packet Delay Measurement 5. Data Service Packet Delay Measurement
Where it is desired to more thoroughly instrument a packet flow and Where it is desired to more thoroughly instrument a packet flow and
to determine the delay of a number of packets it is undesirable to to determine the delay of a number of packets, it is undesirable to
send a large number of RFC6374 packets acting as a proxy data service send a large number of packets acting as proxy data service packets
packets (see Section 4). A method of directly measuring the delay (see Section 4). A method of directly measuring the delay
characteristics of a batch of packets is therefore needed. characteristics of a batch of packets is therefore needed.
Given the long intervals over which it is necessary to measure packet Given the long intervals over which it is necessary to measure packet
loss, it is not necessarily the case that the batch times for the two loss, it is not necessarily the case that the batch times for the two
measurement types would be identical. Thus, we use a technique that measurement types would be identical. Thus, we use a technique that
permits the two measurements are made concurrently and yet relatively permits the two measurements to be made concurrently and yet
independent from each other. The notion that they are relatively relatively independently from each other. The notion that they are
independent arises from the potential for the two batches to overlap relatively independent arises from the potential for the two batches
in time, in which case either the delay batch time will need to be to overlap in time, in which case either the delay batch time will
cut short or the loss time will need to be extended to allow correct need to be cut short or the loss time will need to be extended to
reconciliation of the various counters. allow correct reconciliation of the various counters.
The problem is illustrated in Figure 1 below: The problem is illustrated in Figure 1.
(1) AAAAAAAAAABBBBBBBBBBAAAAAAAAAABBBBBBBBBB (Case 1) AAAAAAAAAABBBBBBBBBBAAAAAAAAAABBBBBBBBBB
SFL Marking of a packet batch for loss measurement SFL marking of a packet batch for loss measurement
(2) AADDDDAAAABBBBBBBBBBAAAAAAAAAABBBBBBBBBB (Case 2) AADDDDAAAABBBBBBBBBBAAAAAAAAAABBBBBBBBBB
SFL Marking of a subset of the packets for delay SFL marking of a subset of the packets for delay
(3) AAAAAAAADDDDBBBBBBBBAAAAAAAAAABBBBBBBBBB (Case 3) AAAAAAAADDDDBBBBBBBBAAAAAAAAAABBBBBBBBBB
SFL Marking of a subset of the packets across a SFL marking of a subset of the packets across a packet loss
packet loss measurement boundary measurement boundary
(4) AACDCDCDAABBBBBBBBBBAAAAAAAAAABBBBBBBBBB (Case 4) AACDCDCDAABBBBBBBBBBAAAAAAAAAABBBBBBBBBB
The case of multiple delay measurements within A case of multiple delay measurements within a packet loss
a packet loss measurement measurement
A & B are packets where loss is being measured where
C & D are pacekts where loss and delay is being measured A and B are packets where loss is being measured.
C and D are packets where loss and delay are being measured.
Figure 1: RFC6734 Query Packet with SFL Figure 1: Query Packet with SFL
In case 1 of Figure 1 we show the case where loss measurement alone In Case 1, we show where loss measurement alone is being carried out
is being carried out on the flow under analysis. For illustrative on the flow under analysis. For illustrative purposes, consider that
purposes consider that 10 packets are used in each flow in the time 10 packets are used in each flow in the time interval being analyzed.
interval being analyzed.
Now consider case 2 of Figure 1 where a small batch of packets need Now consider Case 2, where a small batch of packets need to be
to be analyzed for delay. These are marked with a different SFL type analyzed for delay. These are marked with a different SFL type,
indicating that they are to be monitored for both loss and delay. indicating that they are to be monitored for both loss and delay.
The SFL=A indicates loss batch A, SFL=D indicates a batch of packets The SFL=A indicates loss batch A, and SFL=D indicates a batch of
that are to be instrumented for delay, but SFL D is synonymous with packets that are to be instrumented for delay, but SFL D is
SFL A, which in turn is synonymous with the underlying Forwarding synonymous with SFL A, which in turn is synonymous with the
Equivalence Class (FEC). Thus, a packet marked D will be accumulated underlying Forwarding Equivalence Class (FEC). Thus, a packet marked
into the A loss batch, into the delay statistics and will be "D" will be accumulated into the A loss batch, into the delay
forwarded as normal. Whether the packet is actually counted twice statistics, and will be forwarded as normal. Whether the packet is
(for loss and delay) or whether the two counters are reconciled actually counted twice (for loss and delay) or whether the two
during reporting is a local matter. counters are reconciled during reporting is a local matter.
Now consider case 3 of Figure 1 where a small batch of packets are Now consider Case 3, where a small batch of packets is marked for
marked for delay across a loss batch boundary. These packets need to delay across a loss batch boundary. These packets need to be
be considered as part of batch A or a part of batch B, and any considered as a part of batch A or a part of batch B, and any Query
RFC6374 Query needs to take place after all the packets A or D needs to take place after all packets A or D (whichever option is
(whichever option is chosen) have arrived at the receiving LSR. chosen) have arrived at the receiving Label Switching Router (LSR).
Now consider case 4 of Figure 1. Here we have a case where it is Now consider Case 4. Here, we have a case where it is required to
required to take a number of delay measurements within a batch of take a number of delay measurements within a batch of packets that we
packets that we are measuring for loss. To do this we need two SFLs are measuring for loss. To do this, we need two SFLs for delay (C
for delay (C and D) and alternate between them (on a delay batch by and D) and alternate between them (on a delay-batch-by-delay-batch
delay batch basis) for the purposes of measuring the delay basis) for the purposes of measuring the delay characteristics of the
characteristics of the different batches of packets. different batches of packets.
6. Some Simplifying Rules 6. Some Simplifying Rules
It is possible to construct a large set of overlapping measurement It is possible to construct a large set of overlapping measurement
types, in terms of loss, delay, loss and delay and batch overlap. If types in terms of loss, delay, loss and delay, and batch overlap. If
we allow all combinations of cases, this leads to configuration, we allow all combinations of cases, this leads to configuration,
testing and implementation complexity and hence increased costs. The testing, and implementation complexity and, hence, increased costs.
following simplifying rules represent the default case: The following simplifying rules represent the default case:
1. Any system that needs to measure delay MUST be able to measure 1. Any system that needs to measure delay MUST be able to measure
loss. loss.
2. Any system that is to measure delay MUST be configured to measure 2. Any system that is to measure delay MUST be configured to measure
loss. Whether the loss statistics are collected or not is a loss. Whether the loss statistics are collected or not is a
local matter. local matter.
3. A delay measurement MAY start at any point during a loss 3. A delay measurement MAY start at any point during a loss
measurement batch, subject to rule 4. measurement batch, subject to rule 4.
4. A delay measurement interval MUST be short enough that it will 4. A delay measurement interval MUST be short enough that it will
complete before the enclosing loss batch completes. complete before the enclosing loss batch completes.
5. The duration of a second delay (D in Figure 1 batch must be such 5. The duration of a second delay batch (D in Figure 1) must be such
that all packets from the packets belonging to a first delay that all packets from the packets belonging to a first delay
batch (C in Figure 1)will have been received before the second batch (C in Figure 1) will have been received before the second
delay batch completes. This condition is satisfied when the time delay batch completes. This condition is satisfied when the time
to send a batch is long compared to the network propagation time, to send a batch is long compared to the network propagation time
and is a parameter that can be established by the network and is a parameter that can be established by the network
operator. operator.
Given that the sender controls both the start and duration of a loss Given that the sender controls both the start and duration of a loss
and a delay packet batch, these rules are readily implemented in the and a delay packet batch, these rules are readily implemented in the
control plane. control plane.
7. Multiple Packet Delay Characteristics 7. Multiple Packet Delay Characteristics
A number of methods are described which add to the set of A number of methods are described that add to the set of measurements
measurements originally specified in [RFC6374]. Each of these originally specified in [RFC6374]. Each of these methods has
methods has different characteristics and different processing different characteristics and different processing demands on the
demands on the packet forwarder. The choice of method will depend on packet forwarder. The choice of method will depend on the type of
the type of diagnostic that the operator seeks. diagnostic that the operator seeks.
Three Methods are discussed: Three methods are discussed:
1. Time Buckets 1. Time Buckets
2. Classic Standard Deviation 2. Classic Standard Deviation
3. Average Delay 3. Average Delay
7.1. Method 1: Time Buckets 7.1. Method 1: Time Buckets
In this method the receiving LSR measures the inter-packet gap, In this method, the receiving LSR measures the inter-packet gap,
classifies the delay into a number of delay buckets and records the classifies the delay into a number of delay buckets, and records the
number of packets in each bucket. As an example, if the operator number of packets in each bucket. As an example, if the operator
were concerned about packets with a delay of up to 1us, 2us, 4us, were concerned about packets with a delay of up to 1 μs, 2 μs, 4 μs,
8us, and over 8us then there would be five buckets and packets that 8 μs, and over 8 μs, then there would be five buckets, and packets
arrived up to 1us would cause the 1us bucket counter to increase, that arrived up to 1 μs would cause the "up to 1 μs" bucket counter
between 1us and 2us the 2us bucket counter would increase etc. In to increase. Likewise, for those that arrived between 1 μs and 2 μs,
practice it might be better in terms of processing and potential the "2 μs" bucket counter would increase, etc. In practice, it might
parallelism if, when a packet had a delay relative to its predecessor be better in terms of processing and potential parallelism if both
of 2us, then both the up to 1us and the 2us counter were incremented, the "up to 1 μs" and "2 μs" counters were incremented when a packet
and any more detailed information was calculated in the analytics had a delay relative to its predecessor of 2 μs, and any more
system. detailed information was calculated in the analytics system.
This method allows the operator to see more structure in the jitter This method allows the operator to see more structure in the jitter
characteristics than simply measuring the average jitter, and avoids characteristics than simply measuring the average jitter and avoids
the complication of needing to perform a per packet multiply, but the complication of needing to perform a per-packet multiply but will
will probably need the time intervals between buckets to be probably need the time intervals between buckets to be programmable
programmable by the operator. by the operator.
The packet format of a Time Bucket Jitter Measurement Message is The packet format of a Time Bucket Jitter Measurement message is
shown below: shown below:
0 1 2 3 0 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Version| Flags | Control Code | Message Length | |Version| Flags | Control Code | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| QTF | RTF | RPTF | Reserved | | QTF | RTF | RPTF | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session Identifier | DS | | Session Identifier | DS |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of | Reserved 1 | | Number of | Reserved 1 |
| Buckets | | | Buckets | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interval in 10ns units | | Interval (in 10 ns units) |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number pkts in Bucket | | Number of Pkts in Bucket 1 |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ ~ ~ ~
~ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of Pkts in Bucket N |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ ~ ~ ~
~ TLV Block ~ ~ TLV Block ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Time Bucket Jitter Measurement Message Format Figure 2: Time Bucket Jitter Measurement Message Format
The Version, Flags, Control Code, Message Length, QTF, RTF, RPTF, The Version, Flags, Control Code, Message Length, Querier Timestamp
Session Identifier, Reserved and DS Fields are as defined in section Format (QTF), Responder Timestamp Format (RTF), Responder's Preferred
3.2 of RFC6374. The remaining fields, which are unsigned integers, Timestamp Format (RPTF), Session Identifier, Reserved, and
are as follows: Differentiated Services (DS) fields are as defined in Section 3.2 of
[RFC6374]. The remaining fields, which are unsigned integers, are as
follows:
o Number of Buckets in the measurement * Number of Buckets in the measurement.
o Reserved 1 must be sent as zero and ignored on receipt * Reserved 1 must be sent as zero and ignored on receipt.
o Interval in 10ns units is the inter-packet interval for * Interval (in 10 ns units) is the inter-packet interval for this
this bucket bucket.
o Number Pkts in Bucket is the number of packets found in * Number of Pkts in Bucket 1 is the number of packets found in the
this bucket. first bucket.
* Number of Pkts in Bucket N is the number of packets found in the
Nth bucket, where N is the value in the Number of Buckets field.
There will be a number of Interval/Number pairs depending on the There will be a number of Interval/Number pairs depending on the
number of buckets being specified by the Querier. If an RFC6374 number of buckets being specified by the Querier. If a message is
message is being used to configure the buckets, (i.e. the responder being used to configure the buckets (i.e., the responder is creating
is creating or modifying the buckets according to the intervals in or modifying the buckets according to the intervals in the Query
the Query message), then the Responder MUST respond with 0 packets in message), then the responder MUST respond with 0 packets in each
each bucket until it has been configured for a full measurement bucket until it has been configured for a full measurement period.
period. This indicates that it was configured at the time of the This indicates that it was configured at the time of the last
last response message, and thus the response is valid for the whole response message, and thus, the response is valid for the whole
interval. As per the [RFC6374] convention the Number of pkts in interval. As per the convention in [RFC6374], the Number of Pkts in
Bucket fields are included in the Query message and set to zero. Bucket fields are included in the Query message and set to zero.
Out of band configuration is permitted by this mode of operation. Out-of-band configuration is permitted by this mode of operation.
Note this is a departure from the normal fixed format used in Note this is a departure from the normal fixed format used in
RFC6374. [RFC6374].
The time bucket jitter measurement message is carried over an LSP in The Time Bucket Jitter Measurement message is carried over an LSP in
the way described in [RFC6374] and over an LSP with an SFL as the way described in [RFC6374] and over an LSP with an SFL as
described in Section 9. described in Section 9.
7.2. Method 2 Classic Standard Deviation 7.2. Method 2: Classic Standard Deviation
In this method, provision is made for reporting the following delay In this method, provision is made for reporting the following delay
characteristics: characteristics:
1. Number of packets in the batch (n). 1. Number of packets in the batch (n)
2. Sum of delays in a batch (S) 2. Sum of delays in a batch (S)
3. Maximum Delay. 3. Maximum delay
4. Minimum Delay. 4. Minimum delay
5. Sum of squares of Inter-packet delay (SS). 5. Sum of squares of inter-packet delay (SS)
Characteristics 1 and 2 give the mean delay. Measuring the delay of Characteristics 1 and 2 give the mean delay. Measuring the delay of
each pair in the batch is discussed in Section 7.3. each pair in the batch is discussed in Section 7.3.
Characteristics 3 and 4 give the outliers. Characteristics 3 and 4 give the outliers.
Characteristics 1, 2 and 5 can be used to calculate the variance of Characteristics 1, 2, and 5 can be used to calculate the variance of
the inter-packet gap and hence the standard deviation giving a view the inter-packet gap, hence the standard deviation giving a view of
of the distribution of packet delays and hence the jitter. The the distribution of packet delays and hence the jitter. The equation
equation for the variance (var) is given by: for the variance (var) is given by:
var = (SS - S*S/n)/(n-1) var = (SS - S*S/n)/(n-1)
There is some concern over the use of this algorithm for measuring There is some concern over the use of this algorithm for measuring
variance, because SS and S*S/n can be similar numbers, particularly variance because SS and S*S/n can be similar numbers, particularly
where variance is low. However the method commends it self by not where variance is low. However, the method is acceptable because it
requiring a division in the hardware. does not require a division in the hardware.
7.2.1. Multi-Packet Delay Measurement Message Format 7.2.1. Multi-packet Delay Measurement Message Format
The packet format of a Multi-Packet Delay Measurement Message is The packet format of a Multi-packet Delay Measurement message is
shown below: shown below:
0 1 2 3 0 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Version| Flags | Control Code | Message Length | |Version| Flags | Control Code | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| QTF | RTF | RPTF | Reserved | | QTF | RTF | RPTF | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session Identifier | DS | | Session Identifier | DS |
skipping to change at page 10, line 41 skipping to change at line 470
| Sum of squares of Inter-packet delay | | Sum of squares of Inter-packet delay |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ ~ ~ ~
~ TLV Block ~ ~ TLV Block ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Multi-packet Delay Measurement Message Format Figure 3: Multi-packet Delay Measurement Message Format
The Version, Flags, Control Code, Message Length, QTF, RTF, RPTF, The Version, Flags, Control Code, Message Length, QTF, RTF, RPTF,
Session Identifier, Reserved and DS Fields are as defined in section Session Identifier, Reserved, and DS fields are as defined in
3.2 of RFC6374. The remaining fields are as follows: Section 3.2 of [RFC6374]. The remaining fields are as follows:
o Number of Packets is the number of packets in this batch * Number of Packets is the number of packets in this batch.
o Sum of Delays for Batch is the duration of the batch in the * Sum of Delays for Batch is the duration of the batch in the time
time measurement format specified in the RTF field. measurement format specified in the RTF field.
o Minimum Delay is the minimum inter-packet gap observed during * Minimum Delay is the minimum inter-packet gap observed during the
the batch in the time format specified in the RTF field. batch in the time format specified in the RTF field.
o Maximum Delay is the maximum inter-packet gap observed during * Maximum Delay is the maximum inter-packet gap observed during the
the batch in the time format specified in the RTF field. batch in the time format specified in the RTF field.
The multi-packet delay measurement message is carried over an LSP in The Multi-packet Delay Measurement message is carried over an LSP in
the way described in [RFC6374] and over an LSP with an SFL as the way described in [RFC6374] and over an LSP with an SFL as
described in Section 9. described in Section 9.
7.3. Per Packet Delay Measurement 7.3. Per-Packet Delay Measurement
If detailed packet delay measurement is required then it might be If detailed packet delay measurement is required, then it might be
possible to record the inter-packet gap for each packet pair. In possible to record the inter-packet gap for each packet pair. In
other than exception cases of slow flows or small batch sizes, this cases other than the exceptions of slow flows or small batch sizes,
would create a large (per packet) demand on storage in the this would create a large (per-packet) demand on storage in the
instrumentation system, a large bandwidth to such a storage system instrumentation system, a large bandwidth for such a storage system
and large bandwidth to the analytics system. Such a measurement and large bandwidth for the analytics system. Such a measurement
technique is outside the scope of this document. technique is outside the scope of this document.
7.4. Average Delay 7.4. Average Delay
Introduced in [RFC8321] is the concept of a one way delay measurement Introduced in [RFC9341] is the concept of a one-way delay measurement
in which the average time of arrival of a set of packets is measured. in which the average time of arrival of a set of packets is measured.
In this approach the packet is time-stamped at arrival and the In this approach, the packet is timestamped at arrival, and the
Responder returns the sum of the time-stamps and the number of times- responder returns the sum of the timestamps and the number of
tamps. From this the analytics engine can determine the mean delay. timestamps. From this, the analytics engine can determine the mean
An alternative model is that the Responder returns the time stamp of delay. An alternative model is that the responder returns the
the first and last packet and the number of packets. This later timestamp of the first and last packet and the number of packets.
method has the advantage of allowing the average delay to be This latter method has the advantage of allowing the average delay to
determined at a number of points along the packet path and allowing be determined at a number of points along the packet path and
the components of the delay to be characterized. Unless specifically allowing the components of the delay to be characterized. Unless
configured otherwise, the responder may return either or both types specifically configured otherwise, the responder may return either or
of response and the analytics engine should process the response both types of response, and the analytics engine should process the
appropriately. response appropriately.
The packet format of an Average Delay Measurement Message is shown The packet format of an Average Delay Measurement message is shown
below: below:
0 1 2 3 0 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Version| Flags | Control Code | Message Length | |Version| Flags | Control Code | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| QTF | RTF | RPTF | Reserved | | QTF | RTF | RPTF | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session Identifier | DS | | Session Identifier | DS |
skipping to change at page 12, line 31 skipping to change at line 543
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sum of Timestamps of Batch | | Sum of Timestamps of Batch |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ ~ ~ ~
~ TLV Block ~ ~ TLV Block ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Average Delay Measurement Message Format Figure 4: Average Delay Measurement Message Format
The Version, Flags, Control Code, Message Length, QTF, RTF, RPTF, The Version, Flags, Control Code, Message Length, QTF, RTF, RPTF,
Session Identifier, and DS Fields are as defined in section 3.2 of Session Identifier, and DS fields are as defined in Section 3.2 of
RFC6374. The remaining fields are as follows: [RFC6374]. The remaining fields are as follows:
o Number of Packets is the number of packets in this batch. * Number of Packets is the number of packets in this batch.
o Time of First Packet is the time of arrival of the first * Time of First Packet is the time of arrival of the first packet in
packet in the batch. the batch.
o Time of Last Packet is the time of arrival of the last * Time of Last Packet is the time of arrival of the last packet in
packet in the batch. the batch.
o Sum of Timestamps of Batch. * Sum of Timestamps of Batch.
The average delay measurement message is carried over an LSP in the The Average Delay Measurement message is carried over an LSP in the
way described in [RFC6374] and over an LSP with an SFL as described way described in [RFC6374] and over an LSP with an SFL as described
in Section 9. As is the convention with RFC6374, the Query message in Section 9. As is the convention with [RFC6374], the Query message
contains placeholders for the Response message. The placeholders are contains placeholders for the Response message. The placeholders are
sent as zero. sent as zero.
8. Sampled Measurement 8. Sampled Measurement
In the discussion so far it has been assumed that we would measure In the discussion so far, it has been assumed that we would measure
the delay characteristics of every packet in a delay measurement the delay characteristics of every packet in a delay measurement
interval defined by an SFL of constant color. In [RFC8321] the interval defined by an SFL of constant color. In [RFC9341], the
concept of a sampled measurement is considered. That is the concept of a sampled measurement is considered. That is, the
Responder only measures a packet at the start of a group of packets responder only measures a packet at the start of a group of packets
being marked for delay measurement by a particular color, rather than being marked for delay measurement by a particular color, rather than
every packet in the marked batch. A measurement interval is not every packet in the marked batch. A measurement interval is not
defined by the duration of a marked batch of packets but the interval defined by the duration of a marked batch of packets but the interval
between a pair of RFC6374 packets taking a readout of the delay between a pair of packets taking a readout of the delay
characteristic. This approach has the advantage that the measurement characteristic. This approach has the advantage that the measurement
is not impacted by ECMP effects. is not impacted by ECMP effects.
This sampled approach may be used if supported by the Responder and This sampled approach may be used if supported by the responder and
configured by the opertor. configured by the operator.
9. Carrying RFC6374 Packets over an LSP using an SFL 9. Carrying Packets over an LSP Using an SFL
We illustrate the packet format of an RFC6374 Query message using We illustrate the packet format of a Query message using SFLs for the
SFLs for the case of an MPLS direct loss measurement in Figure 5. case of an MPLS Direct Loss Measurement in Figure 5.
+-------------------------------+ +-------------------------------+
| | | |
| LSP | | LSP |
| Label | | Label |
+-------------------------------+ +-------------------------------+
| | | |
| Synonymous Flow | | Synonymous Flow |
| Label | | Label |
+-------------------------------+ +-------------------------------+
| | | |
| GAL | | GAL |
| | | |
+-------------------------------+ +-------------------------------+
| | | |
| ACH Type = 0xA | | ACH Type = 0xA |
| | | |
+-------------------------------+ +-------------------------------+
| | | |
| RFC6374 Measurement Message | | Measurement Message |
| | | |
| +-------------------------+ | | +-------------------------+ |
| | | | | | | |
| | Fixed-format | | | | Fixed-format | |
| | portion of msg | | | | portion of msg | |
| | | | | | | |
| +-------------------------+ | | +-------------------------+ |
| | | | | | | |
| | Optional SFL TLV | | | | Optional SFL TLV | |
| | | | | | | |
| +-------------------------+ | | +-------------------------+ |
| | | | | | | |
| | Optional Return | | | | Optional Return | |
| | Information | | | | Information | |
| | | | | | | |
| +-------------------------+ | | +-------------------------+ |
| | | |
+-------------------------------+ +-------------------------------+
Figure 5: RFC6734 Query Packet with SFL Figure 5: Query Packet with SFL
The MPLS label stack is exactly the same as that used for the user The MPLS label stack is exactly the same as that used for the user
data service packets being instrumented except for the inclusion of data service packets being instrumented except for the inclusion of
the Generic Associated Channel Label (GAL) [RFC5586] to allow the the Generic Associated Channel Label (GAL) [RFC5586] to allow the
receiver to distinguish between normal data packets and OAM packets. receiver to distinguish between normal data packets and OAM packets.
Since the packet loss measurements are being made on the data service Since the packet loss measurements are being made on the data service
packets, an RFC6374 direct loss measurement is being made, and which packets, an MPLS Direct Loss Measurement is being made, which is
is indicated by the type field in the ACH (Type = 0x000A). indicated by the type field in the Associated Channel Header (ACH)
(Type = 0x000A).
The RFC6374 measurement message consists of the three components, the The measurement message consists of up to three components as
RFC6374 fixed-format portion of the message as specified in [RFC6374] follows.
carried over the ACH channel type specified the type of measurement
being made (currently: loss, delay or loss and delay) as specified in
RFC6374.
Two optional TLVs MAY also be carried if needed. The first is the * The fixed-format portion of the message is carried over the ACH
SFL TLV specified in Section 9.1. This is used to provide the channel. The ACH channel type specifies the type of measurement
implementation with a reminder of the SFL that was used to carry the being made (currently: loss, delay, or loss and delay).
RFC6374 message. This is needed because a number of MPLS
implementations do not provide the MPLS label stack to the MPLS OAM
handler. This TLV is required if RFC6374 messages are sent over UDP
[RFC7876]. This TLV MUST be included unless, by some method outside
the scope of this document, it is known that this information is not
needed by the RFC6374 Responder.
The second set of information that may be needed is the return * (Optional) The SFL TLV specified in Section 9.1 MAY be carried if
information that allows the responder send the RFC6374 response to needed. It is used to provide the implementation with a reminder
the Querier. This is not needed if the response is requested in-band of the SFL that was used to carry the message. This is needed
and the MPLS construct being measured is a point to point LSP, but because a number of MPLS implementations do not provide the MPLS
otherwise MUST be carried. The return address TLV is defined in label stack to the MPLS OAM handler. This TLV is required if
[RFC6374] and the optional UDP Return Object is defined in [RFC7876]. messages are sent over UDP [RFC7876]. This TLV MUST be included
unless, by some method outside the scope of this document, it is
known that this information is not needed by the responder.
Where a measurement other than an MPLS direct loss measurement is to * (Optional) The Return Information MAY be carried if needed. It
be made, the appropriate RFC6374 measurement message is used (for allows the responder send the response to the Querier. This is
example, one of the new types defined in this document) and this is not needed if the response is requested in band and the MPLS
indicated to the receiver by the use of the corresponding ACH type. construct being measured is a point-to-point LSP, but it otherwise
MUST be carried. The Return Address TLV is defined in [RFC6374],
and the optional UDP Return Object is defined in [RFC7876].
9.1. RFC6374 SFL TLV Where a measurement other than an MPLS Direct Loss Measurement is to
be made, the appropriate measurement message is used (for example,
one of the new types defined in this document), and this is indicated
to the receiver by the use of the corresponding ACH type.
The RFC6374 SFL TLV is shown in Figure 6. This contains the SFL that 9.1. Extending RFC 6374 with SFL TLV
was carried in the label stack, the FEC that was used to allocate the
SFL and the index into the batch of SLs that were allocated for the The [RFC6374] SFL TLV is shown in Figure 6. This contains the SFL
FEC that corresponds to this SFL. that was carried in the label stack, the FEC that was used to
allocate the SFL, and the index (into the batch of SFLs that were
allocated for the FEC) that corresponds to this SFL.
0 1 2 3 0 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 | Length |MBZ| SFL Batch | SFL Index | | Type | Length |MBZ| SFL Batch | SFL Index |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SFL | Reserved | | SFL | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FEC | | FEC |
. . . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: SFL TLV Figure 6: SFL TLV
Where: Where:
Type Type is set to Synonymous Flow Label (SFL-TLV). Type Set to Synonymous Flow Label (SFL-TLV).
Length The length of the TLV as specified in RFC6374. Length The length of the TLV is as specified in [RFC6374].
MBZ MUST be sent as zero and ignored on receive. MBZ MUST be sent as zero and ignored on receive.
SFL Batch The SFL batch that this SFL was allocated as part SFL Batch An identifier for a collection of SFLs grouped
of see [I-D.bryant-mpls-sfl-control] together for management and control purposes.
SPL Index The index into the list of SFLs that were assigned SFL Index The index of this SFL within the list of SFLs that
against the FEC that corresponds to the SFL. were assigned for the FEC.
Multiple SFLs can be assigned to a FEC each Multiple SFLs can be assigned to a FEC, each with
with different actions. This index is an optional different actions. This index is an optional
convenience for use in mapping between the TLV convenience for use in mapping between the TLV and the
and the associated data structures in the LSRs. associated data structures in the LSRs. The use of
The use of this feature is agreed between the this feature is agreed upon between the two parties
two parties during configuration. It is not required, during configuration. It is not required but is a
but is a convenience for the receiver if both parties convenience for the receiver if both parties support
support the facility, the facility.
SFL The SFL used to deliver this packet. This is an MPLS SFL The SFL used to deliver this packet. This is an MPLS
label which is a component of a label stack entry as label that is a component of a label stack entry as
defined in Section 2.1 of [RFC3032]. defined in Section 2.1 of [RFC3032].
Reserved MUST be sent as zero and ignored on receive. Reserved MUST be sent as zero and ignored on receive.
FEC The Forwarding Equivalence Class that was used to FEC The Forwarding Equivalence Class that was used to
request this SFL. This is encoded as per request this SFL. This is encoded as per
Section 3.4.1 of [RFC5036] Section 3.4.1 of [RFC5036].
This information is needed to allow for operation with hardware that This information is needed to allow for operation with hardware that
discards the MPLS label stack before passing the remainder of the discards the MPLS label stack before passing the remainder of the
stack to the OAM handler. By providing both the SFL and the FEC plus stack to the OAM handler. By providing both the SFL and the FEC plus
index into the array of allocated SFLs a number of implementation index into the array of allocated SFLs, a number of implementation
types are supported. types are supported.
10. RFC6374 Combined Loss-Delay Measurement 10. Combined Loss/Delay Measurement Using SFL
This mode of operation is not currently supported by this This mode of operation is not currently supported by this
specification. specification.
11. Privacy Considerations 11. Privacy Considerations
The inclusion of originating and/or flow information in a packet The inclusion of originating and/or flow information in a packet
provides more identity information and hence potentially degrades the provides more identity information and hence potentially degrades the
privacy of the communication. Whilst the inclusion of the additional privacy of the communication. While the inclusion of the additional
granularity does allow greater insight into the flow characteristics granularity does allow greater insight into the flow characteristics,
it does not specifically identify which node originated the packet it does not specifically identify which node originated the packet
other than by inspection of the network at the point of ingress, or other than by inspection of the network at the point of ingress or
inspection of the control protocol packets. This privacy threat may inspection of the control protocol packets. This privacy threat may
be mitigated by encrypting the control protocol packets, regularly be mitigated by encrypting the control protocol packets, regularly
changing the synonymous labels and by concurrently using a number of changing the synonymous labels, and by concurrently using a number of
such labels. such labels.
12. Security Considerations 12. Security Considerations
The security considerations documented in [RFC6374] and [RFC8372] The security considerations documented in [RFC6374] and [RFC8372]
(which in turn calls up [RFC7258] and [RFC5920]) are applicable to (which in turn calls up [RFC5920] and [RFC7258]) are applicable to
this protocol. this protocol.
The issue noted in Section 11 is a security consideration. There are The issue noted in Section 11 is a security consideration. There are
no other new security issues associated with the MPLS dataplane. Any no other new security issues associated with the MPLS data plane.
control protocol used to request SFLs will need to ensure the Any control protocol used to request SFLs will need to ensure the
legitimacy of the request. legitimacy of the request.
An attacker that manages to corrupt the RFC6374 SFL TLV Section 9.1 An attacker that manages to corrupt the [RFC6374] SFL TLV in
could disrupt the measurements in a way that the RFC6374 responder is Section 9.1 could disrupt the measurements in a way that the
unable to detect. However, the network opertator is likely to notice [RFC6374] responder is unable to detect. However, the network
the anomalous network performance measurements, and in any case operator is likely to notice the anomalous network performance
normal MPLS network security proceedures make this type of attack measurements, and in any case, normal MPLS network security
extremely unlikley. procedures make this type of attack extremely unlikely.
13. IANA Considerations 13. IANA Considerations
13.1. Allocation of MPLS Generalized Associated Channel (G-ACh) Types 13.1. Allocation of MPLS Generalized Associated Channel (G-ACh) Types
As per the IANA considerations in [RFC5586] updated by [RFC7026] and As per the IANA considerations in [RFC5586] updated by [RFC7026] and
[RFC7214], IANA is requested to allocate the following codeponts in [RFC7214], IANA has allocated the following values in the "MPLS
the "MPLS Generalized Associated Channel (G-ACh) Type" registry, in Generalized Associated Channel (G-ACh) Types" registry, in the
the "Generic Associated Channel (G-ACh) Parameters" name space: "Generic Associated Channel (G-ACh) Parameters" registry group:
Value Description Reference
----- --------------------------------- -----------
TBD RFC6374 Time Bucket Jitter Measurement This
TBD RFC6374 Multi-Packet Delay This +========+================================+===========+
Measurement | Value | Description | Reference |
+========+================================+===========+
| 0x0010 | Time Bucket Jitter Measurement | RFC 9571 |
+--------+--------------------------------+-----------+
| 0x0011 | Multi-packet Delay Measurement | RFC 9571 |
+--------+--------------------------------+-----------+
| 0x0012 | Average Delay Measurement | RFC 9571 |
+--------+--------------------------------+-----------+
TBD RFC6374 Average Delay Measurement This Table 1
13.2. Allocation of MPLS Loss/Delay TLV Object 13.2. Allocation of MPLS Loss/Delay TLV Object
IANA is requested to allocate a new TLV from the 0-127 range of the IANA has allocated the following TLV from the 0-127 range of the
MPLS Loss/Delay Measurement TLV Object Registry in the "Generic "MPLS Loss/Delay Measurement TLV Object" registry in the "Generic
Associated Channel (G-ACh) Parameters" namespace: Associated Channel (G-ACh) Parameters" registry group:
Type Description Reference
---- --------------------------------- ---------
TBD Synonymous Flow Label This
A value of 4 is recommended.
RFC Editor please delete this para
[RFC3032][I-D.bryant-mpls-sfl-control][RFC5036]
14. Acknowledgments
The authors thank Benjamin Kaduk and Elwyn Davies for their thorough
and thoughtful review of this document.
15. Contributing Authors
Zhenbin Li
Huawei
Email: lizhenbin@huawei.com
Siva Sivabalan +======+=======================+===========+
Ciena Corporation | Type | Description | Reference |
Email: ssivabal@ciena.com +======+=======================+===========+
| 4 | Synonymous Flow Label | RFC 9571 |
+------+-----------------------+-----------+
16. References Table 2
16.1. Normative References 14. References
[I-D.bryant-mpls-sfl-control] 14.1. Normative References
Bryant, S., Swallow, G., and S. Sivabalan, "A Simple
Control Protocol for MPLS SFLs", draft-bryant-mpls-sfl-
control-09 (work in progress), December 2020.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y., [RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001, Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001,
<https://www.rfc-editor.org/info/rfc3032>. <https://www.rfc-editor.org/info/rfc3032>.
skipping to change at page 20, line 5 skipping to change at line 846
[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>.
[RFC8957] Bryant, S., Chen, M., Swallow, G., Sivabalan, S., and G. [RFC8957] Bryant, S., Chen, M., Swallow, G., Sivabalan, S., and G.
Mirsky, "Synonymous Flow Label Framework", RFC 8957, Mirsky, "Synonymous Flow Label Framework", RFC 8957,
DOI 10.17487/RFC8957, January 2021, DOI 10.17487/RFC8957, January 2021,
<https://www.rfc-editor.org/info/rfc8957>. <https://www.rfc-editor.org/info/rfc8957>.
16.2. Informative References 14.2. Informative References
[RFC3270] Le Faucheur, F., Wu, L., Davie, B., Davari, S., Vaananen, [RFC3270] Le Faucheur, F., Ed., Wu, L., Davie, B., Davari, S.,
P., Krishnan, R., Cheval, P., and J. Heinanen, "Multi- Vaananen, P., Krishnan, R., Cheval, P., and J. Heinanen,
Protocol Label Switching (MPLS) Support of Differentiated "Multi-Protocol Label Switching (MPLS) Support of
Services", RFC 3270, DOI 10.17487/RFC3270, May 2002, Differentiated Services", RFC 3270, DOI 10.17487/RFC3270,
<https://www.rfc-editor.org/info/rfc3270>. May 2002, <https://www.rfc-editor.org/info/rfc3270>.
[RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS [RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, DOI 10.17487/RFC5920, July 2010, Networks", RFC 5920, DOI 10.17487/RFC5920, July 2010,
<https://www.rfc-editor.org/info/rfc5920>. <https://www.rfc-editor.org/info/rfc5920>.
[RFC5921] Bocci, M., Ed., Bryant, S., Ed., Frost, D., Ed., Levrau, [RFC5921] Bocci, M., Ed., Bryant, S., Ed., Frost, D., Ed., Levrau,
L., and L. Berger, "A Framework for MPLS in Transport L., and L. Berger, "A Framework for MPLS in Transport
Networks", RFC 5921, DOI 10.17487/RFC5921, July 2010, Networks", RFC 5921, DOI 10.17487/RFC5921, July 2010,
<https://www.rfc-editor.org/info/rfc5921>. <https://www.rfc-editor.org/info/rfc5921>.
[RFC7190] Villamizar, C., "Use of Multipath with MPLS and MPLS [RFC7190] Villamizar, C., "Use of Multipath with MPLS and MPLS
Transport Profile (MPLS-TP)", RFC 7190, Transport Profile (MPLS-TP)", RFC 7190,
DOI 10.17487/RFC7190, March 2014, DOI 10.17487/RFC7190, March 2014,
<https://www.rfc-editor.org/info/rfc7190>. <https://www.rfc-editor.org/info/rfc7190>.
[RFC7258] Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an [RFC7258] Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an
Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May
2014, <https://www.rfc-editor.org/info/rfc7258>. 2014, <https://www.rfc-editor.org/info/rfc7258>.
[RFC8321] Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli,
L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi,
"Alternate-Marking Method for Passive and Hybrid
Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321,
January 2018, <https://www.rfc-editor.org/info/rfc8321>.
[RFC8372] Bryant, S., Pignataro, C., Chen, M., Li, Z., and G. [RFC8372] Bryant, S., Pignataro, C., Chen, M., Li, Z., and G.
Mirsky, "MPLS Flow Identification Considerations", Mirsky, "MPLS Flow Identification Considerations",
RFC 8372, DOI 10.17487/RFC8372, May 2018, RFC 8372, DOI 10.17487/RFC8372, May 2018,
<https://www.rfc-editor.org/info/rfc8372>. <https://www.rfc-editor.org/info/rfc8372>.
[RFC9341] Fioccola, G., Ed., Cociglio, M., Mirsky, G., Mizrahi, T.,
and T. Zhou, "Alternate-Marking Method", RFC 9341,
DOI 10.17487/RFC9341, December 2022,
<https://www.rfc-editor.org/info/rfc9341>.
Acknowledgments
The authors thank Benjamin Kaduk and Elwyn Davies for their thorough
and thoughtful review of this document.
Contributors
Zhenbin Li
Huawei
Email: lizhenbin@huawei.com
Siva Sivabalan
Ciena Corporation
Email: ssivabal@ciena.com
Authors' Addresses Authors' Addresses
Stewart Bryant Stewart Bryant (editor)
Futurewei Technologies Inc. Futurewei Technologies Inc.
Email: sb@stewartbryant.com Email: sb@stewartbryant.com
George Swallow George Swallow
Southend Technical Center Southend Technical Center
Email: swallow.ietf@gmail.com Email: swallow.ietf@gmail.com
Mach Chen Mach(Guoyi) Chen
Huawei Huawei
Email: mach.chen@huawei.com Email: mach.chen@huawei.com
Giuseppe Fioccola Giuseppe Fioccola
Huawei Technologies Huawei Technologies
Email: giuseppe.fioccola@huawei.com Email: giuseppe.fioccola@huawei.com
Gregory Mirsky Gregory Mirsky
ZTE Corp. ZTE Corp.
Email: gregimirsky@gmail.com Email: gregimirsky@gmail.com
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