IPFIX export of Segment Routing IPv6 information
draft-patki-srv6-ipfix-00

Abstract

This docuemnt introduces new IP Flow Information Exchange (IPFIX) information elemements for exporting IPv6 Segment Routing Header (SRH).

Status of This Memo

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Copyright Notice

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Table of Contents

• 1. Introduction
• 1.1. Requirements Language
• 2. New IPFIX Information Elements
• 3. IANA Considerations
• 4. Security Considerations
• 5. Acknowledgements
• 6. References
• 6.1. Normative References
• 6.2. Informative References
• Appendix A. Encoding Example
• A.1. Template Record
• A.2. Data Set
• Author's Address

1. Introduction

IP Flow Information Export (IPFIX) [RFC7011] provides network administrators with traffic flow information using the Information Elements (IEs) defined in the "IPFIX Information Elements" registry [IANA-IPFIX]. Based on the traffic flow information, network administrators know the amount and direction of the traffic in their network and can then optimize the network when needed. For example, the collected information could be used for traffic monitoring and, optionally, for traffic optimization according to the operator's policy.

A new type of Routing Extension Header called Segment Routing Header (SRH) is defined by [RFC8754] which is used for applying Segment Routing on IPv6 data plane. This document defined new IPFIX IEs to export the contents of SRH.

Currently this document is limited to exporting based SRH excluding the TLV, however, further versions of this document intend to include TLVs and variations in the SRH that may be defined in the near future.

1.1. 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].

2. New IPFIX Information Elements

This section defines new IPFIX IEs corresponding to various fields in the SRH.

ipv6SRHLastEntry

The index (zero based) in the Segment List in the SRH, of the last element of the Segment List.

ipv6SRHFlags

8-bit flags defined in the SRH.

ipv6SRHTag

Tag is an identifier that marks a packet as part of a class or group of packets, e.g., packets sharing the same set of properties. This information element contains the value of the Tag field.

ipv6SRHSegment

128-bit IPv6 address that represents an SRv6 segment.

ipv6SRHSegmentList

A basicList [RFC6313][RFC7012] of ipv6SRHSegment that contains the Segment List in the SRH header. Like in the SRH header, the basicList is encoded starting from the last segment of the SR Policy. That is, the first element of the basicList contains the last segment of the SR Policy, the second element contains the penultimate segment of the SR Policy, and so on. This information element has variable length.

3. IANA Considerations

This document specifies IPFIX IEs to enable export of Segment Routing IPv6 information. IANA needs to assign the following Element IDs for these IEs in the "IPFIX Information Elements" registry [IANA-IPFIX]:

--------------------------------------------------------------------
| Element |       Name         | Abstract   | Data Type  | Refer-  |
|   ID    |                    | Data Type  | Semantics  | ence    |
--------------------------------------------------------------------
| TBD1    | ipv6SRHLastEntry   | unsigned8  | identifier | RFC8754 |
| TBD2    | ipv6SRHFlags       | unsigned8  | flags      | RFC8754 |
| TBD3    | ipv6SRHTag         | unsigned16 | identifier | RFC8754 |
| TBD4    | ipv6SRHSegment     | ipv6address| default    | RFC8754 |
| TBD5    | ipv6SRHSegmentList | basicList  | list       | RFC8754 |
--------------------------------------------------------------------

    

4. Security Considerations

The security considerations in [RFC7011] apply.

5. Acknowledgements

TBD

6. References

6.1. Normative References

6.2. Informative References

Appendix A. Encoding Example

    Observed SRH headers:

    SRH 1:
    Segments Left = 2, Last Entry = 2, Flags = 0, Tag = 0,
    Segment List = 1111::1, 2222::2, 3333::3

    SRH 2:
    Segments Left = 1, Last Entry = 1, Flags = 0, Tag = 100,
    Segment List = 4444::4, 5555::5

    SRH 3:
    Segments Left = 1, Last Entry = 2, Flags = 0, Tag = 200,
    Segment List = 6666::6, 7777::7, 8888::8     
 

In this section, an example is provided to show IPFIX encoding format for the newly introduced IEs. Template definition and data set corresponding to 3 observed SRH headers are illustrated.

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 = 24             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      Template ID = 256        |      Field Count = 4          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0|   ipv6SRHLastEntry = TBD1   |      Field Length = 1         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0|     ipv6SRHFlags = TBD2     |      Field Length = 1         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0|      ipv6SRHTag = TBD3      |      Field Length = 2         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0|  ipv6SRHSegmentList = TBD5  |      Field Length = 0xFFFF    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 

Figure 1: Sample Template

Sample template consisting of the new IEs:

A.2. Data Set

Data set for the observed SRH headers using the template defined above:

    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 = 168        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  ipv6SRHLast  | ipv6SRHFlags  |        ipv6SRHTag = 0         |
   |  Entry = 2    | = 0           |                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      255      |        List Length = 53       |semantic=allof |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     ipv6SRHSegment = TBD4     |        Field Length = 16      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Segment List[0] = 1111::1  (16 bytes)             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Segment List[1] = 2222::2  (16 bytes)             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Segment List[2] = 3333::3  (16 bytes)             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  ipv6SRHLast  | ipv6SRHFlags  |        ipv6SRHTag = 100       |
   |  Entry = 1    | = 0           |                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      255      |        List Length = 37       |semantic=allof |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     ipv6SRHSegment = TBD4     |        Field Length = 16      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Segment List[0] = 4444::4  (16 bytes)             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Segment List[1] = 5555::5  (16 bytes)             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  ipv6SRHLast  | ipv6SRHFlags  |        ipv6SRHTag = 200       |
   |  Entry = 2    | = 0           |                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      255      |        List Length = 53       |semantic=allof |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     ipv6SRHSegment = TBD4     |        Field Length = 16      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Segment List[0] = 6666::6  (16 bytes)             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Segment List[1] = 7777::7  (16 bytes)             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Segment List[2] = 8888::8  (16 bytes)             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 

Figure 2: Data Set

Author's Address