Network Working Group Z. Li
Internet-Draft L. Li
Intended status: Standards Track Huawei
Expires: September 12, 2019 March 11, 2019
PCEP Flow Specification for SRv6
draft-li-pce-pcep-flowspec-srv6-00
Abstract
This draft proposes PCEP flow specification rules that are used to
filter SRv6 packets.
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."
This Internet-Draft will expire on September 12, 2019.
Copyright Notice
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document authors. All rights reserved.
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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 TLV for SRv6 . . . . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . 6
5. IANA . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
6. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 6
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
Traffic flows may be categorized and described using "Flow
Specifications". [RFC5575] defines the Flow Specification and
describes how Flow Specification Components are used to describe
traffic flows. [RFC5575]defines how Flow Specifications may be
distributed in BGP to allow specific traffic flows to be associated
with routes.
Segment Routing (SR) for unicast traffic has been proposed to cope
with the use cases 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[I-D.filsfils-spring-srv6-network-programming] defined the
SRv6 network programming concept and its most basic functions. SRv6
SID will have the form LOC:FUNCT:ARGS::.
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
PCEP[RFC5440] defines the communication between a Path Computation
Client (PCC) and a PCE, or between PCE and PCE, enabling computation
of path for Traffic Engine. PCEP Flow Specification (PCEP-FS)
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[I-D.ietf-pce-pcep-flowspec] specifies a set of extensions to PCEP to
support dissemination of Flow Specification.
[I-D.ietf-pce-pcep-flowspec] defined 3 new Flow Specification TLV
Types: TBD5 for Route Distinguisher(RD), TBD6 for IPv4 Multicast
Flow, TBD7 for IPv6 Multicast Flow. This document specifies a new
subset of PCEP Flow Specification TLV Types to support Segment
Routing over IPv6 data plane (SRv6) filtering.
2. Definitions and Acronyms
o FS: Flow Specification
o SR: Segment Routing
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 TLV for SRv6
This document proposes new flow specifications rules that is encoded
in PCEP FS TLVs. The following new FS TLV types are defined:
o Whole SID
Type TBD1 - Whole SID/BSID
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
+-------------------------------+-------------------------------+
| Type=[TBD1] | Length |
+-------------------------------+-------------------------------+
~ [operator, value]+ ~
+---------------------------------------------------------------+
This type of new TLV contains a set 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 |lt |gt |eq | reserve |
+---+---+---+---+---+---+---+---+
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Where:
e - end-of-list bit. Set in the last {op, value} pair in the list.
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.
lt - less than comparison between data and value.
gt - greater than comparison between data and value.
eq - equality between data and value.
The bits lt, gt, and eq can be combined to produce 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
[I-D.filsfils-spring-srv6-network-programming]
o Some bits of SID to match
For some scenarios route policy with the whole128 bits SID matching
is too long and not necessary.
[I-D.filsfils-spring-srv6-network-programming] defined the format of
SID is LOC:FUNCT:ARGS::. In some scenarios, traffic packets can just
match Locator, Function ID, Argument or combine of these different
fields rather than whole 128 bits SID. This document defines a set
of new component type TBD2 to reduce the length of matching.
Type TBD2 - Some bits of SID
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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
+-------------------------------+-------------------------------+
| Type=[TBD2] | Length |
+-------------------------------+-------------------------------+
~ [operator, value]+ ~
+---------------------------------------------------------------+
This type of new TLV contains a set 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 | type |reserve|
+---+---+---+---+---+---+---+---+
Where:
e - end-of-list bit. Set in the last {op, value} pair in the list.
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.
type:
0000 : SID's LOC bits
0001 : SID's FUNCT bits 0010 :
SID's LOC:FUNCT bits
0011 : SID's FUNCT:ARGS bits
The value field is encoded as SID with mask to match bits as type
defined:
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) ~
+---------------------------------------------------------------+
~ Mask ~
+---------------------------------------------------------------+
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4. Security Considerations
No new security issues are introduced to the PECP protocol by this
specification.
5. IANA
IANA is requested to a new entry in "Flow Spec component types
registry" with the following values:
+--------------------------------------------+
| Type | RFC or Draft | Description |
+--------------------------------------------+
| TBD1 | This Draft | SID |
+--------------------------------------------+
| TBD2 | This Draft | Some bits of SID |
+--------------------------------------------+
6. Contributors
TBD
7. Acknowledgments
TBD
8. References
[I-D.filsfils-spring-srv6-network-programming]
Filsfils, C., Camarillo, P., Leddy, J.,
daniel.voyer@bell.ca, d., Matsushima, S., and Z. Li, "SRv6
Network Programming", draft-filsfils-spring-srv6-network-
programming-07 (work in progress), February 2019.
[]
Filsfils, C., Previdi, S., Leddy, J., Matsushima, S., and
d. daniel.voyer@bell.ca, "IPv6 Segment Routing Header
(SRH)", draft-ietf-6man-segment-routing-header-16 (work in
progress), February 2019.
[I-D.ietf-idr-segment-routing-te-policy]
Previdi, S., Filsfils, C., Jain, D., Mattes, P., Rosen,
E., and S. Lin, "Advertising Segment Routing Policies in
BGP", draft-ietf-idr-segment-routing-te-policy-05 (work in
progress), November 2018.
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[I-D.ietf-pce-pcep-flowspec]
Dhody, D., Farrel, A., and Z. Li, "PCEP Extension for Flow
Specification", draft-ietf-pce-pcep-flowspec-03 (work in
progress), February 2019.
[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>.
[RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440,
DOI 10.17487/RFC5440, March 2009,
<https://www.rfc-editor.org/info/rfc5440>.
[RFC5575] Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J.,
and D. McPherson, "Dissemination of Flow Specification
Rules", RFC 5575, DOI 10.17487/RFC5575, August 2009,
<https://www.rfc-editor.org/info/rfc5575>.
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
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