Network Working Group T. Graf
Internet-Draft Swisscom
Intended status: Informational 18 February 2022
Expires: 22 August 2022
Export of Segment Routing IPv6 Information in
IP Flow Information Export (IPFIX)
draft-tgraf-opsawg-ipfix-srv6-srh-01
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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. IPFIX Information Elements . . . . . . . . . . . . . . . . . 2
3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . 6
Appendix A. IPFIX Encoding Example . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 9
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.
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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
* how many packets are forwarded or dropped
* if dropped, for which reasons,
* identify the control plane protocol which defined the active
segment,
* the SRv6 segment list and
* how many SRv6 segments are left.
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.
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+-------+--------------------+------------+-----------+-------------+
|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
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+-------+--------------------+--------------------------------------+
| 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:
* Please replace TBD1 - TBD12 with the values allocated by IANA
* Please replace the [RFC-to-be] with the RFC number assigned to
this document
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, July 2011,
<https://www.rfc-editor.org/info/rfc6313>.
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[RFC7012] Claise, B., Ed. and B. Trammell, Ed., "Information Model
for IP Flow Information Export (IPFIX)", RFC 7012,
DOI 10.17487/RFC7012, September 2013,
<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, 16 February 2022,
<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, 20 October 2021,
<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, 10
January 2022, <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, 15 January
2020, <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, March 2020,
<https://www.rfc-editor.org/info/rfc8754>.
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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].
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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
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Author's Address
Thomas Graf
Swisscom
Binzring 17
CH-8045 Zurich
Switzerland
Email: thomas.graf@swisscom.com
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