Internet-Draft IPFIX Segment Routing IPv6 Information February 2022
Graf Expires 22 August 2022 [Page]
Workgroup:
Network Working Group
Internet-Draft:
draft-tgraf-opsawg-ipfix-srv6-srh-01
Published:
Intended Status:
Informational
Expires:
Author:
T. Graf
Swisscom

Export of Segment Routing IPv6 Information in IP Flow Information Export (IPFIX)

Abstract

This document introduces new IP Flow Information Export (IPFIX) information elements to identify the SRv6 Segment Routing Header dimensions and SRv6 Control Plane Protocol that traffic is being forwarded with.

Status of This Memo

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

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This Internet-Draft will expire on 22 August 2022.

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Table of Contents

1. Introduction

A new type of Routing Extension Header called Segment Routing Header (SRH) is defined by [RFC8754] which is used for applying Segment Routing (SR) on the IPv6 data plane.

Three routing protocol extensions, OSPFv3 Extensions [I-D.li-lsr-ospfv3-srv6-extensions], IS-IS Extensions [I-D.ietf-lsr-isis-srv6-extensions], BGP Prefix Segment Identifiers (Prefix-SIDs) [I-D.ietf-bess-srv6-services] and one Path Computation Element Communication Protocol (PCEP) Extension [I-D.ietf-pce-segment-routing-ipv6] have been defined to propagate Segment Identifiers (SIDs) for the IPv6 data plane.

This document defines seven new IPFIX Information Elements (IEs) and two new subregistries within the "IPFIX Information Elements" registry [RFC7012], respectively for the new SRH dimensions and routing protocol and PCEP extensions.

2. IPFIX Information Elements

This section defines and describes the new IPFIX IEs.

ipv6SRHFlags
8-bit flags defined in the SRH.
ipv6SRHTag
16-bit tag field defined in the SRH that marks a packet as part of a class or group of packets sharing the same set of properties.
ipv6SRHSegment
128-bit IPv6 address that represents an SRv6 segment.
ipv6SRHSegmentList
Ordered basicList [RFC6313] of zero or more 128-bit IPv6 addresses in the SRH that represents the SRv6 segment list. The Segment List is encoded starting from the active segment of the SR Policy.
ipv6SRHSegmentsLeft
8-bit unsigned integer defining the number of route segments remaining to reach the end of the segment list.
ipv6SRHSection
Exposes the SRH and its TLV's as defined in section 2 of [RFC8754] as series of n octets.
ipv6SRHSegmentType
Name of the routing protocol or PCEP extension from where the active SRv6 segment has been learned from.

3. Use Cases

By using ipv6SRHSegmentList(TBD4), ipv6SRHSegmentsLeft (TBD5), ipv6SRHSegment1Type(TBD7) and forwardingStatus(89) it is possible to identify

4. IANA Considerations

This document requests IANA to create new IEs and two new subregistries called ""IPFIX IPv6 SRH Flags (TBD1)" and IPFIX IPv6 SRH Segment type (TBD5)" under the "IPFIX Information Elements" registry [RFC7012] available at [IANA-IPFIX] and assign the following code initial points.


+-------+--------------------+------------+-----------+-------------+
|Element|       Name         |  Abstract  | Data Type |  Reference  |
|   ID  |                    |  Data Type | Semantics |             |
+-------+--------------------+------------+-------------------------+
| TBD1  | ipv6SRHFlag        | unsigned8  | flags     | [RFC-to-be],|
|       |                    |            |           | RFC8754     |
+-------+--------------------+------------+-------------------------+
| TBD2  | ipv6SRHTag         | unsigned16 | identifier| [RFC-to-be],|
|       |                    |            |           | RFC8754     |
+-------+--------------------+------------+-------------------------+
| TBD3  | ipv6SRHSegment     | ipv6address| default   | [RFC-to-be],|
|       |                    |            |           | RFC8754     |
+-------+--------------------+------------+-------------------------+
| TBD4  | ipv6SRHSegmentList | basiclist  | list      | [RFC-to-be],|
|       |                    |            |           | RFC8754     |
+-------+--------------------+------------+-------------------------+
| TBD5  | ipv6SRHSegmentsLeft| unsigned8  | quantity  | [RFC-to-be],|
|       |                    |            |           | RFC8754     |
+-------+--------------------+------------+-------------------------+
| TBD6  | ipv6SRHSection     | octetArray | default   | [RFC-to-be] |
+-------+--------------------+------------+-------------------------+
| TBD7  | ipv6SRHSegmentType | unsigned8  | identifier| [RFC-to-be] |
+-------+--------------------+------------+-------------------------+

  Table 1: Creates IEs in the "IPFIX Information Elements" registry


+--------+-------------------+--------------------------------------+
| Value  |    Description    |              Reference               |
+--------+-------------------+--------------------------------------+
| 0-7    | Unassigned        |                                      |
+--------+-------------------+--------------------------------------+

      Table 2: Creates "IPFIX IPv6 SRH Flags (TBD1)" subregistry


+-------+--------------------+--------------------------------------+
| Value |     Description    |              Reference               |
+-------+--------------------+--------------------------------------+
| TBD8  | Unknown            | [RFC-to-be]                          |
|       |                    |                                      |
+-------+--------------------+--------------------------------------+
| TBD9  | Path Computation   | [RFC-to-be],                         |
|       | Element            | draft-ietf-pce-segment-routing-ipv6  |
+-------+--------------------+--------------------------------------+
| TB10  | OSPFv3             | [RFC-to-be],                         |
|       | Segment Routing    | draft-li-ospf-ospfv3-srv6-extensions |
+-------+--------------------+--------------------------------------+
| TBD11 | IS-IS              | [RFC-to-be]                          |
|       | Segment Routing    | draft-ietf-lsr-isis-srv6-extensions  |
+-------+--------------------+--------------------------------------+
| TBD12 | BGP Segment        | [RFC-to-be],                         |
|       | Routing Prefix-SID | draft-ietf-bess-srv6-services        |
+-------+--------------------+--------------------------------------+

  Table 3: Creates "IPFIX IPv6 SRH Segment type (TBD7)" subregistry

Note to the RFC-Editor:

5. Security Considerations

There exists no significant extra security considerations regarding the allocation of these new IPFIX IEs compared to [RFC7012].

6. Acknowledgements

I would like to thank Pierre Francois, Yao Liu, Paolo Lucente and Benoit Claise for their review and valuable comments.

7. References

7.1. Normative References

[RFC6313]
Claise, B., Dhandapani, G., Aitken, P., and S. Yates, "Export of Structured Data in IP Flow Information Export (IPFIX)", RFC 6313, DOI 10.17487/RFC6313, , <https://www.rfc-editor.org/info/rfc6313>.
[RFC7012]
Claise, B., Ed. and B. Trammell, Ed., "Information Model for IP Flow Information Export (IPFIX)", RFC 7012, DOI 10.17487/RFC7012, , <https://www.rfc-editor.org/info/rfc7012>.

7.2. Informative References

[I-D.ietf-bess-srv6-services]
Dawra, G., Filsfils, C., Talaulikar, K., Raszuk, R., Decraene, B., Zhuang, S., and J. Rabadan, "SRv6 BGP based Overlay Services", Work in Progress, Internet-Draft, draft-ietf-bess-srv6-services-11, , <https://www.ietf.org/archive/id/draft-ietf-bess-srv6-services-11.txt>.
[I-D.ietf-lsr-isis-srv6-extensions]
Psenak, P., Filsfils, C., Bashandy, A., Decraene, B., and Z. Hu, "IS-IS Extensions to Support Segment Routing over IPv6 Dataplane", Work in Progress, Internet-Draft, draft-ietf-lsr-isis-srv6-extensions-18, , <https://www.ietf.org/archive/id/draft-ietf-lsr-isis-srv6-extensions-18.txt>.
[I-D.ietf-pce-segment-routing-ipv6]
Li, C., Negi, M., Sivabalan, S., Koldychev, M., Kaladharan, P., and Y. Zhu, "PCEP Extensions for Segment Routing leveraging the IPv6 data plane", Work in Progress, Internet-Draft, draft-ietf-pce-segment-routing-ipv6-11, , <https://www.ietf.org/internet-drafts/draft-ietf-pce-segment-routing-ipv6-11.txt>.
[I-D.li-lsr-ospfv3-srv6-extensions]
Li, Z., Hu, Z., Cheng, D., Talaulikar, K., and P. Psenak, "OSPFv3 Extensions for SRv6", Work in Progress, Internet-Draft, draft-li-lsr-ospfv3-srv6-extensions-00, , <https://www.ietf.org/archive/id/draft-li-lsr-ospfv3-srv6-extensions-00.txt>.
[IANA-IPFIX]
"IANA, "IP Flow Information Export (IPFIX) Entities"", <https://www.iana.org/assignments/ipfix/ipfix.xhtml>.
[RFC8754]
Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J., Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header (SRH)", RFC 8754, DOI 10.17487/RFC8754, , <https://www.rfc-editor.org/info/rfc8754>.

Appendix A. IPFIX Encoding Example

In this section an example is provided to show the encoding format for the newly introduced IEs.


+-----+------+-----+--------+---------------------------------------|
| SRH | SRH  | SRH | Segment|             Segment List              |
| Nr  | Flags| Tag | Type   |                                       |
+-----+------+-----+--------+---------------------------------------+
| 1   | 0    | 123 | IS-IS  | 2001:db8::1, 2001:db8::2, 2001:db8::3 |
+-----+------+-----+--------+---------------------------------------+
| 2   | 0    | 456 | IS-IS  | 2001:db8::4, 2001:db8::5              |
+-----+------+-----+--------+---------------------------------------+
| 3   | 0    | 789 | IS-IS  | 2001:db8::6                           |
+-----+------+-----+--------+---------------------------------------+

     Table 4: 3 observed SRH headers and their routing protocol

A.1. Template Record 


    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |          SET ID = 2           |       Length = 41             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      Template ID = 256        |      Field Count = 4          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0|     ipv6SRHFlags = TBD2     |      Field Length = 1         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0|      ipv6SRHTag = TBD3      |      Field Length = 2         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0|  ipv6SRHSegmentType = TBD6  |      Field Length = 1         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0|    ipv6SRHSegment = TBD4    |      Field Length = 16        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0|  ipv6SRHSegmentList = TBD6  |      Field Length = 0xFFFF    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

               Table 4: Template Record Encoding Format

In this example, the Template ID is 256, which will be used in the Data Record. The field length for ipv6SRHSegmentList is 0xFFFF, which means the length of this IE is variable, and the actual length of this IE is indicated by the List Length field in the basicList format as per [RFC6313].

A.2. Data Set

The data set is represented as follows:


    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         SET ID = 256          |           Length = 136        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | ipv6SRHFlags  |        ipv6SRHTag = 123       | ipv6SRHSegment|
   | = 0           |                               | Type = TBD11  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      255      |        List Length = 53       |semantic=      |
   |               |                               |ordered        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     ipv6SRHSegment = TBD4     |        Field Length = 16      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Segment List[0] = 2001:db8::1  (16 bytes)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Segment List[1] = 2001:db8::2  (16 bytes)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Segment List[2] = 2001:db8::3  (16 bytes)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | ipv6SRHFlags  |        ipv6SRHTag = 456       | ipv6SRHSegment|
   | = 0           |                               | Type = TBD11  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      255      |        List Length = 37       |semantic=      |
   |               |                               |ordered        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     ipv6SRHSegment = TBD4     |        Field Length = 16      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Segment List[0] = 2001:db8::4  (16 bytes)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Segment List[1] = 2001:db8::5  (16 bytes)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | ipv6SRHFlags  |        ipv6SRHTag = 789       | ipv6SRHSegment|
   | = 0           |                               | Type = TBD11  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      255      |        List Length = 21       |semantic=      |
   |               |                               |ordered        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     ipv6SRHSegment = TBD4     |        Field Length = 16      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Segment List[0] = 2001:db8::6  (16 bytes)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                  Table 5: Data Set Encoding Format

Author's Address

Thomas Graf
Swisscom
Binzring 17
CH-8045 Zurich
Switzerland