Internet-Draft Post-Stack MNA Solution March 2023
Rajamanickam, et al. Expires 11 September 2023 [Page]
Workgroup:
MPLS Working Group
Internet-Draft:
draft-jags-mpls-ps-mna-hdr-00
Published:
Intended Status:
Standards Track
Expires:
Authors:
J. Rajamanickam, Ed.
Cisco Systems, Inc.
R. Gandhi, Ed.
Cisco Systems, Inc.
R. Zigler
Broadcom
T. Li
Juniper Networks
J. Dong
Huawei Technologies

Post-Stack MPLS Network Action (MNA) Solution

Abstract

This document defines the Post-Stack MPLS Network Action (MNA) solution for carrying Network Actions and Ancillary Data after the MPLS label stack based on In-Stack MNA solution defined in draft-ietf-mpls-mna-hdr. MPLS Network Actions can be used to influence packet forwarding decisions, carry additional OAM information in the MPLS packet or perform user-defined operations. This document addresses the MNA requirements specified in draft-ietf-mpls-mna-requirements. This document follows the MNA framework specified in draft-ietf-mpls-mna-fwk.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."

This Internet-Draft will expire on 11 September 2023.

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Table of Contents

1. Introduction

[RFC3032] defines the encoding of the MPLS label stack, the basic structure used to define a forwarding path. Forthcoming applications require MPLS packets to perform special network actions and carry optional Ancillary Data (AD) that can affect the packet forwarding decision or trigger OAM logging, for example. Ancillary Data can be used to carry additional information, such as a IOAM, Path tracing etc. Several MNA applications are described in [I-D.ietf-mpls-mna-usecases]. User-defined network actions allow new, local actions to be defined. In some cases, more Ancillary Data may required to be carried in the MPLS header, so these kind of Network Actions and its Ancillary data are encoded after the MPLS Stack. These are called as Post-Stack Data.

This document defines the syntax and semantics of Post-Stack Network Actions and their corresponding Ancillary Data based on the In-Stack MNA solution defined in [I-D.ietf-mpls-mna-hdr]. This document addresses the requirements specified in [I-D.ietf-mpls-mna-requirements]. This document follows the framework specified in [I-D.ietf-mpls-mna-fwk].

2. Conventions Used in This Document

2.1. Requirements Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.

2.2. Abbreviations

The terminology defined in [I-D.ietf-mpls-mna-fwk] and [I-D.ietf-mpls-mna-requirements] are used in this document.

Table 1: Abbreviations
Abbreviation Meaning Reference
AD Ancillary Data [I-D.ietf-mpls-mna-requirements]
bSPL Base Special Purpose Label [RFC9017]
BOS Bottom Of Stack [RFC3032]
HBH Hop-By-Hop Scope [I-D.ietf-mpls-mna-fwk]
I2E Ingress-To-Egress Scope [I-D.ietf-mpls-mna-fwk]
IHS I2E, HBH, or Select Scope [I-D.ietf-mpls-mna-hdr]
ISD In-Stack Data [I-D.ietf-mpls-mna-requirements]
LSE Label Stack Entry [RFC3032]
MNA MPLS Network Actions [I-D.ietf-mpls-mna-fwk]
NAI Network Action Indicator [I-D.ietf-mpls-mna-requirements]
NAL Network Action Length [I-D.ietf-mpls-mna-hdr]
NAS Network Action Sub-Stack [I-D.ietf-mpls-mna-fwk]
NASL Network Action Sub-Stack Length [I-D.ietf-mpls-mna-hdr]
OAM Operations And Management [RFC4377]
P Post-Stack Network Action Indicator Bit This document
PSD Post-Stack Data [I-D.ietf-mpls-mna-requirements] and [I-D.ietf-mpls-mna-fwk]
PSMNA Post-Stack MPLS Network Action This document
PS-MNA-OP Post-Stack MPLS Network Action Opcode This document
TC Traffic Class [RFC5462]
TTL Time To Live [RFC3032]

3. Overview

A Flag in the In-Stack NAS header [I-D.ietf-mpls-mna-hdr] indicates the presence of the Post-Stack MNA. The Post-Stack MNA's are encoded after the MPLS Label Stack (BoS).

The Post-Stack MNA encoding contains two main parts:

4. Post-Stack Network Action Indicator

A reserved bit (21st bit from left in LSE Format B) in the In-Stack MNA header described in [I-D.ietf-mpls-mna-hdr] is used to indicate the presence of the Post-Stack Network Action.


 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|   Opcode    |        Data             |P|IHS|S| Res |U|  NASL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1

The below are the flags applicable to Post-Stack MNA encoding purposes defined in [I-D.ietf-mpls-mna-hdr].

5. Post-Stack Network Action Encoding

The Post-Stack Network Action and its Ancillary Data are encoded after the MPLS Label Stack (BoS). The Post-Stack Network Action may carry multiple Post-Stack Network Actions and its corresponding Ancillary Data.

This consist of two main parts:

5.1. Post-Stack Network Action Top Header

This header is overall for all the Post-Stack Network Actions that are encoded.


 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|N N N N|Version|   PS-MNA-LEN  |    TYPE = POST-STACK-MNA      |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2

5.2. Post-Stack Network Action Header

This header encodes a single Post-Stack Network Action. Using this scheme, multiple Post-Stack Network Action and its corresponding Ancillary data can be encoded.


 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  PS-MNA-OP  |         PS ANCILLARY DATA     |R|R|    PS-NAL   |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3

6. In-Stack Special Opcode Allocation

Some of the In-Stack MNA Opcodes are allocated to support Post-Stack Network Action. They are as follows.

6.1. Post-Stack Network Action Offset

Opcode: 1

Purpose: This opcode carries the start offset of the Post-Stack Network Action Top Header.

LSE Format: B

Data: The data value of the LSE contains the offset from the MPLS BOS in units of 4 octets. This allows the Generic Control Word (0000b) [RFC4385] and G-ACh (0001b) [RFC5586] fields to be placed immediately after the BOS. In the absence of this opcode, the Post-Stack Network Action is encoded immediately after the MPLS BOS. A data value of 1 indicates that the PAH starts 4 octets after the BOS.

Scope: This opcode can be used with any scope.

6.2. PS-IS-NA Ordering

Opcode: 4

Purpose: In cases where the ordering of network action is significant and where some of the network actions reside in Post-Stack Network Action, this opcode can be used to insert Post-Stack network actions into the order of execution. The 'P' bit and 'O' bit MUST be set in the NAS's Format B LSE if this opcode is used.

LSE Format: B, C, D

Data: The data field contains one or more 7-bit Post-Stack MNA Opcode. When used with LSE Format B, only one PS MNA Opcode is carried. Two PS MNA opcodes can be carried in a Format C LSE, and if Format D LSEs are used, each may carry up to three PS MNA opcodes. The PS MNA opcodes are the stored concatenated in the most significant bits of the data field. If multiple indicators are carried, the most significant PS MNA opcode is evaluated to the least significant. PS MNA opcodes do not span LSEs. If some PS MNA opcode positions are not to be used, then the opcode should be set to value 0.

Scope: This opcode can be used with any scope.

7. Node Capability Signaling

The ingress node which is adding a Post-Stack MNA MUST make sure that the egress node is capable of MNA and removes the Post-Stack MNA.

The above capability signaling will be added in appropriate protocols. Signaling details are outside the scope of this document.

8. Processing the Network Action Sub-Stack

This section defines the specific responsibilities for nodes along a MPLS path.

8.1. Encapsulating Node Responsibilities

The encapsulating node MAY add Post-Stack MNA to the packet in accordance with its policies, the placement restrictions, and the limitations.

The encapsulating node MUST NOT add a Post-Stack MNA to the packet if the decapsulation node does not support Post-Stack MNA.

If the encapsulating node is also a transit node, then it MUST also respect transit node responsibilities.

8.2. Transit Node Responsibilities

A transit node MAY change the Ancillary Data in the Post-Stack MNA.

A transit node MUST respect the Unknown Action Handling value encoded in the NAS.

A node that removes the last copy of a NAS that has the P bit set MUST remove all Post-Stack Network Actions.

8.3. Penultimate Node Responsibilities

In addition to the transit node responsibilities above, the penultimate node MUST NOT remove the last copy of a HBH or I2E NAS when it is exposed after removing the forwarding (transport) label. This allows the egress node to process the NAS.

8.4. Decapsulating Node Responsibilities

The decapsulating node MUST remove any Post-Stack MNA it receives.

9. Security Considerations

The security considerations in [RFC3032] also apply to this document.

In addition, MNA creates a new dimension in security concerns:

10. IANA Considerations

10.1. Post-Stack MNA Nibble

This document requests that IANA allocate a value (TBA1) for the Post-Stack MNA Nibble (NNNN) to indicate the start of the Post-Stack Network Actions. The reference should be this document.

10.2. In-Stack Network Action Opcodes

The In-Stack Network Action Opcodes for In-Stack Network Action Opcode registry are defined in the document as follows

Table 2: In-Stack Network Action Flags With Ancillary Data Registry
Opcode Description Reference
1 Offset of start of Post-Stack Network Action Header This document
4 PS-IS-NA Ordering This document

10.3. Post-Stack Network Action Opcodes

This document requests that IANA create a new registry with the name "Post-Stack Network Action Opcodes". The registration procedure for this registry is "IETF Review". The fields are "Opcode" (integer), "Description" (string), and "Reference" (string). Opcode is an integer 0-127.

The initial assignments for this registry are:

Table 3: Post-Stack Network Action Opcodes Registry
Opcode Description Reference
0 Reserved This document
1-110 Unassigned
111-126 Private Use

11. Appendix A: Examples

11.1. Post-Stack Network Action Encoding

11.1.1. NAS that only Indicates Post-Stack NAs 


 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|           Label=MNA bSPL              | TC  |S|    TTL        |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  Opcode=2   |            0            |1|IHS|S| Res |U| NASL=0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~                                                               ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                                             |1|               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~                   Post-Stack Network Actions                  ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~                                                               ~
~                           Payload                             ~
~                                                               ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: NAS encoding only Post-Stack NAs

In some cases, the NAS may encode only the presence of Post-Stack NAs. In this case, the P-Bit is set. The IHS field indicates the scope of the Post-Stack NAs (I2E, HBH, Select).

11.1.2. NAS with both In-Stack and Post-Stack NAs 


 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|          Label=MNA bSPL               | TC  |0|    TTL        |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=2    |            0            |1|IHS|0| Res |U| NASL=1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=2    |        Flag-Based NAIs        |S| NAIs  | NAL=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~                                                               ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                                             |1|               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~              Post-Stack Network Actions                       ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~                                                               ~
~                           Payload                             ~
~                                                               ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: NAS with In-Stack and Post-Stack NAs

In some cases, the NAS may encode In-Stack NAs and indicate the presence of Post-Stack NAs. In this case, P-Bit is set. The NASL is set to "1", indicating the presence of one additional LSE. The IHS field indicates the scope of both the In-Stack and Post-Stack NAs.

11.1.3. NASes with Multiple Scopes 


 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|          Label=MNA bSPL               | TC  |0|    TTL        |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=2    |            0            |0| 1 |0| Res |U| NASL=1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=2    |        Flag-Based NAIs        |0| NAIs  | NAL=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|          Label=MNA bSPL               | TC  |0|    TTL        |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  Opcode=2   |            0            |1| 0 |1| Res |U| NASL=0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~              Post-Stack Network Actions                       ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~                                                               ~
~                           Payload                             ~
~                                                               ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: NASes with multiple scopes

In some cases the label stack may need to carry In-Stack NAs with Hop-By-Hop scope and Post-Stack NAs with I2E scope. In this case, there will be two NASes in the label stack. In this case, the first NAS will encode the In-Stack NA with the Hop-By-Hop scope and the second NAS will encode the presence of I2E scoped Post-Stack NAs.

11.2. Post-Stack Network Action with two Opcodes 


 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|          Label=MNA bSPL               | TC  |0|    TTL        |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|   Opcode    |        Data             |1|IHS|1| Res |U| NASL=0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|N N N N|Version|PS-MNA-LEN = 3 |    TYPE = POST-STACK-MNA      |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  PS-MNA-OP=2|         PS ANCILLARY DATA     |R|R|  PS-NAL = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  PS-MNA-OP=3|         PS ANCILLARY DATA     |R|R|  PS-NAL = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                       PS ANCILLARY DATA                       |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                                                               |
|                     Optional Payload + Padding                |
|                                                               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: Post-Stack NA Example

This is an example of Post-Stack MNA encoding, that encode two different Post-Stack Network Actions.

Details:

  • PS-MNA-LEN=3: This is the Total Length of Post-Stack MNAs.
  • PS-MNA-OP=2: Post-Stack MNA Opcode "2".
  • PS-NAL=0: Post-Stack Network Action does not contain any additional data.
  • PS-MNA-OP=3: Post-Stack MNA Opcode "3".
  • PS-NAL=1: Post-Stack Network Action contains 1 additional word to carry its Ancillary data.

11.3. Network Action Processing Order

The semantics of a network action can vary widely and the results of processing one network action may affect the processing of a subsequent network action.

11.3.1. Post-Stack NA Processing Order

By default, Post-Stack NAs follow the ordering of the encoding. However, the PS-IS-NA ordering opcode can be used to override the default ordering and interleave Post-Stack network actions with In-Stack network actions.

In some cases, Post-Stack NAs needs to be processed before In-Stack NAs. This section shows how to prioritize the Post-Stack NAs over In-Stack NAs.



 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|          Label=MNA bSPL               | TC  |0|    TTL        |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=8    |      Ancillary Data     |1|IHS|0| Res |U| NASL=3|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=2    |      Flag-Based NAIs          |0| NAIs  | NAL=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=4    |      Post-Stack NA 6          |0|PS-NAI | NAL=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opcode=7    |      Ancillary Data           |S|  AD   | NAL=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8: Post-Stack and In-Stack NA processing order

In the above example, opcode 8 is processed first, then the Flag-Based NAIs, followed by Post-Stack NA Opcode 6, and finally opcode 7.

12. References

12.1. Normative References

[I-D.ietf-mpls-mna-fwk]
Andersson, L., Bryant, S., Bocci, M., and T. Li, "MPLS Network Actions Framework", Work in Progress, Internet-Draft, draft-ietf-mpls-mna-fwk-02, , <https://datatracker.ietf.org/doc/html/draft-ietf-mpls-mna-fwk-02>.
[I-D.ietf-mpls-mna-requirements]
Bocci, M., Bryant, S., and J. Drake, "Requirements for MPLS Network Actions", Work in Progress, Internet-Draft, draft-ietf-mpls-mna-requirements-04, , <https://datatracker.ietf.org/doc/html/draft-ietf-mpls-mna-requirements-04>.
[I-D.ietf-mpls-mna-usecases]
Saad, T., Makhijani, K., Song, H., and G. Mirsky, "Use Cases for MPLS Network Action Indicators and MPLS Ancillary Data", Work in Progress, Internet-Draft, draft-ietf-mpls-mna-usecases-01, , <https://datatracker.ietf.org/doc/html/draft-ietf-mpls-mna-usecases-01>.
[I-D.ietf-mpls-mna-hdr]
Rajamanickam, J., Gandhi, R., Zigler, R., Song, H., and K. Kompella, "MPLS Network Action (MNA) Sub-Stack Solution", Work in Progress, Internet-Draft, draft-ietf-mpls-mna-hdr-00, , <https://datatracker.ietf.org/doc/html/draft-ietf-mpls-mna-hdr-00>.
[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
[RFC3032]
Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y., Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack Encoding", RFC 3032, DOI 10.17487/RFC3032, , <https://www.rfc-editor.org/info/rfc3032>.
[RFC4377]
Nadeau, T., Morrow, M., Swallow, G., Allan, D., and S. Matsushima, "Operations and Management (OAM) Requirements for Multi-Protocol Label Switched (MPLS) Networks", RFC 4377, DOI 10.17487/RFC4377, , <https://www.rfc-editor.org/info/rfc4377>.
[RFC4385]
Bryant, S., Swallow, G., Martini, L., and D. McPherson, "Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for Use over an MPLS PSN", RFC 4385, DOI 10.17487/RFC4385, , <https://www.rfc-editor.org/info/rfc4385>.
[RFC5462]
Andersson, L. and R. Asati, "Multiprotocol Label Switching (MPLS) Label Stack Entry: "EXP" Field Renamed to "Traffic Class" Field", RFC 5462, DOI 10.17487/RFC5462, , <https://www.rfc-editor.org/info/rfc5462>.
[RFC5586]
Bocci, M., Ed., Vigoureux, M., Ed., and S. Bryant, Ed., "MPLS Generic Associated Channel", RFC 5586, DOI 10.17487/RFC5586, , <https://www.rfc-editor.org/info/rfc5586>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.
[RFC9017]
Andersson, L., Kompella, K., and A. Farrel, "Special-Purpose Label Terminology", RFC 9017, DOI 10.17487/RFC9017, , <https://www.rfc-editor.org/info/rfc9017>.

Acknowledgments

The authors would like to thank the authors and contributors of the draft-ietf-mpls-mna-hdr as this document borrows some text from the earlier version of that document.

Contributors

The following people have substantially contributed to this document:


Jisu Bhattacharya
Cisco Systems, Inc.
Email: jisu@cisco.com


John Drake
Juniper Networks
United States
Email: jdrake@juniper.net
Figure 9

Authors' Addresses

Jaganbabu Rajamanickam (editor)
Cisco Systems, Inc.
Canada
Rakesh Gandhi (editor)
Cisco Systems, Inc.
Canada
Royi Zigler
Broadcom
Tony Li
Juniper Networks
Jie Dong
Huawei Technologies
Beijing
China