BGP Flow Specification for SRv6
draft-li-idr-flowspec-srv6-05
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Replaced".
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|
|---|---|---|---|
| Authors | Zhenbin Li , Lei Li, Huaimo Chen , Christoph Loibl , Gyan Mishra , Yanhe Fan , Yongqing Zhu , Lei Liu , Xufeng Liu | ||
| Last updated | 2021-07-23 (Latest revision 2021-03-29) | ||
| Replaced by | draft-ietf-idr-flowspec-srv6 | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
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| Additional resources | Mailing list discussion | ||
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draft-li-idr-flowspec-srv6-05
Network Working Group Z. Li
Internet-Draft L. Li
Intended status: Standards Track Huawei
Expires: September 30, 2021 H. Chen
Futurewei
C. Loibl
Next Layer Communications
G. Mishra
Verizon Inc.
Y. Fan
Casa Systems
Y. Zhu
China Telecom
L. Liu
Fujitsu
X. Liu
Volta Networks
March 29, 2021
BGP Flow Specification for SRv6
draft-li-idr-flowspec-srv6-05
Abstract
This document proposes extensions to BGP Flow Specification for SRv6
for filtering SRv6 packets that match a sequence of conditions.
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].
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."
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This Internet-Draft will expire on September 30, 2021.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Definitions and Acronyms . . . . . . . . . . . . . . . . . . 3
3. The Flow Specification Encoding for SRv6 . . . . . . . . . . 4
3.1. Type TBD1 - Whole SID . . . . . . . . . . . . . . . . . . 4
3.2. Type TBD2 - Some bits of SID . . . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 7
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.1. Normative References . . . . . . . . . . . . . . . . . . 7
7.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
[RFC8955] describes in details about a new BGP NLRI to distribute a
flow specification, which is an n-tuple comprising a sequence of
matching criteria that can be applied to IP traffic. [RFC8956]
extends [RFC8955] to make it also usable and applicable to IPv6 data
packets. [I-D.ietf-idr-flowspec-l2vpn] extends the flow-spec rules
for layer 2 Ethernet packets.
Segment Routing (SR) for unicast traffic has been proposed to cope
with the usecases in traffic engineering, fast re-reroute, service
chain, etc. SR architecture can be implemented over an IPv6 data
plane using a new type of Segment Routing Header (SRH)
[I-D.ietf-6man-segment-routing-header]. SRv6 Network Programming
[RFC8986] defines the SRv6 network programming concept and its most
basic functions. An SRv6 SID may have the form of LOC:FUNCT:ARGS::.
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LOC: Each operator is free to use the locator length it chooses.
Most often the LOC part of the SID is routable and leads to the node
which instantiates that SID.
FUNCT: The FUNCT part of the SID is an opaque identification of a
local function bound to the SID. (e.g. End: Endpoint, End.X, End.T,
End.DX2 etc.).
ARGS: A function may require additional arguments that would be
placed immediately after the FUNCT.
This document specifies two new BGP Flow Specification (FS) component
types to support Segment Routing over IPv6 data plane (SRv6)
filtering. The match field is destination address of IPv6 header,
but it's a SID copy from SRH rather than a traditional IPv6 address
(refer to Figure 1).
+-----------------------------+
IPv6 Header| SA | DA |<--Match field of this document
+--------------------^--------+
|
+--------------------|--------+
| +-------------+ | +-------------------+
| | Segment[0] +-------> Loc | Func | Args |
| +-------------+ | +-------------------+
| | Segment[1] | |
| +-------------+ |
| | ... | |
SR Header| +-------------+ |
| | Segment[n] | |
| +-------------+ |
| +-------------+ |
| ~ Option TLV ~ |
| +-------------+ |
+-----------------------------+
Figure 1: Match Field
2. Definitions and Acronyms
o FS: Flow Specification
o BGP-FS: Border Gateway Protocol (BGP) Flow Specification (FS)
o SR: Segment Routing
o SRH: SR Header.
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o SRv6: IPv6 Segment Routing, SRv6 is a method of forwarding IPv6
packets on the network based on the concept of source routing.
o SID: Segment Identifier
o BSID: Binding SID
3. The Flow Specification Encoding for SRv6
The Flow Specification NLRI-type consists of several optional
components, each of which begins with a type field (1 octet) followed
by a variable length parameter. 13 component types are defined in
[RFC8955] and [RFC8956] for IPv4 and IPv6. This document defines two
new component types for SRv6.
3.1. Type TBD1 - Whole SID
Encoding: <type (1 octet), [op, value]+>
Contains a list of {operator, value} pairs that are used to match the
SID/binding SID or a range of whole SID.
The operator byte is encoded as:
0 1 2 3 4 5 6 7
+---+---+---+---+---+---+---+---+
| e | a | 0 | 0 | 0 |lt |gt |eq |
+---+---+---+---+---+---+---+---+
Where:
e - end-of-list bit. Set in the last {op, value} pair in the
sequence.
a - AND bit. If unset, the previous term is logically ORed with the
current one. If set, the operation is a logical AND. It should be
unset in the first operator byte of a sequence. The AND operator has
higher priority than OR for the purposes of evaluating logical
expressions.
0 - SHOULD be set to 0 on NLRI encoding, and MUST be ignored during
decoding.
lt - less than comparison between data and value.
gt - greater than comparison between data and value.
eq - equality between data and value.
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The bits lt, gt, and eq can be combined to match the SID or a range
of SID (e.g. less than SID1 and greater than SID2).
The value field is encoded as:
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
+---------------------------------------------------------------+
~ SID(128bits) ~
+---------------------------------------------------------------+
The format of SID is described in
[I-D.ietf-6man-segment-routing-header] and [RFC8986]
3.2. Type TBD2 - Some bits of SID
For some scenarios route policy with the whole 128 bits SID matching
is too long and not necessary. [RFC8986] defines the format of SID
is LOC:FUNCT:ARGS::. In some scenarios, traffic packets can just
match Locator, Function ID, Argument or some combinations of these
different fields rather than whole 128 bits SID. In order to match
the Function ID (FUNCT), the Locator (LOC) needs to be examined and
matched first. The new component type TBD2 defined below is for
matching some bits of SID.
Encoding: <type (1 octet), [op, value]+>
Contains a list of {operator, value} pairs that are used to match
some bits of SID.
The operator byte is encoded as:
0 1 2 3 4 5 6 7
+---+---+---+---+---+---+---+---+
| e | a | field type|lt |gt |eq |
+---+---+---+---+---+---+---+---+
Where:
e and a are the same as defined in Section "Type TBD1 - Whole SID".
field type:
000 : SID's LOC bits
001 : SID's FUNCT bits
010 : SID's LOC:FUNCT bits
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011 : SID's FUNCT:ARGS bits
lt - less than comparison between data' and value'.
gt - greater than comparison between data' and value'.
eq - equality between data' and value'.
The data' and value' used in lt, gt and eq are indicated by the field
type in a operator and its corresponding length in the value field
following the operator.
The value field is encoded below as the lengths in bits of LOC, FUNCT
and ARGS followed by the SID rounding up to bytes:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LOC Length | FUNCT Length | ARGS Length | SID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ SID(continue) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Where:
LOC Length : 1-octet field indicating the length in bits of LOC in
SID.
FUNCT Length : 1-octet field indicating the length in bits of FUNCT
in SID.
ARGS Length : 1-octet field indicating the length in bits of ARGS in
SID.
SID : the SID containing LOC, FUNCT and ARGS, and rounding up to
bytes.
4. Security Considerations
No new security issues are introduced to the BGP protocol by this
specification over the security considerations in [RFC8955] and
[RFC8956].
5. IANA Considerations
This section complies with [RFC7153].
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Under "Flow Spec IPv6 Component Types" registry, IANA is requested to
assign the following values:
+-----------+-------------------+----------------+
| Value | Name | Reference |
+-----------+-------------------+----------------+
| TBD1 (14) | Whole SID | This Document |
+-----------+-------------------+----------------+
| TBD2 (15) | Some bits of SID | This Document |
+-----------+-------------------+----------------+
6. Acknowledgments
The authors would like to thank Joel Halpern, Shunwan Zhuang and
Rainsword Wang for their valuable suggestions and comments on this
draft.
7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC7153] Rosen, E. and Y. Rekhter, "IANA Registries for BGP
Extended Communities", RFC 7153, DOI 10.17487/RFC7153,
March 2014, <https://www.rfc-editor.org/info/rfc7153>.
[RFC8955] Loibl, C., Hares, S., Raszuk, R., McPherson, D., and M.
Bacher, "Dissemination of Flow Specification Rules",
RFC 8955, DOI 10.17487/RFC8955, December 2020,
<https://www.rfc-editor.org/info/rfc8955>.
[RFC8956] Loibl, C., Ed., Raszuk, R., Ed., and S. Hares, Ed.,
"Dissemination of Flow Specification Rules for IPv6",
RFC 8956, DOI 10.17487/RFC8956, December 2020,
<https://www.rfc-editor.org/info/rfc8956>.
7.2. Informative References
[I-D.ietf-6man-segment-routing-header]
Filsfils, C., Dukes, D., Previdi, S., Leddy, J.,
Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
(SRH)", draft-ietf-6man-segment-routing-header-26 (work in
progress), October 2019.
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[I-D.ietf-idr-flowspec-l2vpn]
Weiguo, H., Eastlake, D., Litkowski, S., and S. Zhuang,
"BGP Dissemination of L2 Flow Specification Rules", draft-
ietf-idr-flowspec-l2vpn-16 (work in progress), November
2020.
[RFC8986] Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer,
D., Matsushima, S., and Z. Li, "Segment Routing over IPv6
(SRv6) Network Programming", RFC 8986,
DOI 10.17487/RFC8986, February 2021,
<https://www.rfc-editor.org/info/rfc8986>.
Authors' Addresses
Zhenbin Li
Huawei
156 Beiqing Road
Beijing, 100095
P.R. China
Email: lizhenbin@huawei.com
Lei Li
Huawei
156 Beiqing Road
Beijing 100095
P.R. China
Email: lily.lilei@huawei.com
Huaimo Chen
Futurewei
Boston, MA
USA
Email: Huaimo.chen@futurewei.com
Christoph Loibl
Next Layer Communications
Mariahilfer Guertel 37/7
Vienna 1150
AT
Email: cl@tix.at
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Gyan S. Mishra
Verizon Inc.
13101 Columbia Pike
Silver Spring MD 20904
USA
Phone: 301 502-1347
Email: gyan.s.mishra@verizon.com
Yanhe Fan
Casa Systems
USA
Email: yfan@casa-systems.com
Yongqing Zhu
China Telecom
109, West Zhongshan Road, Tianhe District
Guangzhou 510000
China
Email: zhuyq.gd@chinatelecom.cn
Lei Liu
Fujitsu
USA
Email: liulei.kddi@gmail.com
Xufeng Liu
Volta Networks
McLean, VA
USA
Email: xufeng.liu.ietf@gmail.com
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