Internet DRAFT - draft-cheng-spring-srv6-resource-programming
draft-cheng-spring-srv6-resource-programming
SPRING Working Group W. Cheng
Internet-Draft W. Jiang
Intended status: Standards Track China Mobile
Expires: 10 September 2023 R. Chen
D. Zhao
ZTE Corporation
C. Lin
New H3C Technologies
9 March 2023
Network Resource Programming with SRv6
draft-cheng-spring-srv6-resource-programming-01
Abstract
This document defines a new SRv6 network function which can be used
for SRv6 Network Resource Programming.
Status of This Memo
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This Internet-Draft will expire on 10 September 2023.
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. End.NRP Behavior . . . . . . . . . . . . . . . . . . . . . . 3
4. Use Cases for End.NRP behavior . . . . . . . . . . . . . . . 4
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . . 6
8. Normative References . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
The concept of Network Resource Partition is introduced in
[I-D.ietf-teas-ietf-network-slices]. A Network Resource Partition
(NRP) is a set of network resources that are allocated from the
underlay network to carry a specific set of network traffic and meet
the required SLOs and SLEs.
Segment Routing (SR) [RFC8402] leverages the source routing paradigm.
An ingress node steers a packet through an ordered list of
instructions, called "segments". Each one of these instructions
represents a function to be called at a specific location in the
network. A function is locally defined on the node where it is
executed and may range from simply moving forward in the segment list
to any complex user-defined behavior.
SR Policy is an ordered list of segments (i.e., instructions) that
represent a source-routed policy. The packets steered into an SR
Policy have an ordered list of segments associated with that SR
Policy.
Since the SRv6 Endpoint behavior defined in [RFC8986] are not
associated with a set of network resource partition of the interface
for slices/slice aggregate(e.g.End.X just forwards to an endpoint
with cross-connect to a 'layer-3 adjacency' or L2 bundles).
Therefore, SRv6 policies can't achieve strict SLA guarantees.
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[I-D.ietf-spring-resource-aware-segments]extends the SR paradigm by
associating SIDs with network resource attributes. On the basis of
[I-D.ietf-spring-resource-aware-segments], this document defines a
new SRv6 Endpoint behavior which can be used to associate with a set
of network resource partition (e.g. bandwidth, buffer and queue
resources ) Programming, called End.NRP. By using the End.NRP SID to
build its segment list , the SRv6 policy has the capability to
program network resources and achieve strict SLA guarantees.
2. 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 RFC 2119 [RFC2119].
3. End.NRP Behavior
This section defines a new SRv6 Endpoint behavior which can be used
to associate with a set of snetwork resource partition (e.g.
bandwidth, buffer and queue resources ) Programming, called End.NRP.
The End.NRP is a variant of the End.X behavior defined in [RFC8986].
Any SID instance of End.NRP behavior is associated with two sets：J1
and J2.
J1：one or more L3 adjacencies or L2 bundles
J2：NRP of J1
When N receives a packet destined to S and S is a local End.NRP SID,
the line S15 from the End processing defined in [RFC8986] is replaced
by the following:
S15. Submit the packet to the IPv6 module for transmission to
the new destination via a member of J1, using the NRP
identified by J2
This End.NRP SID can support the Penultimate Segment Pop (PSP) of the
SRH, Ultimate Segment Pop (USP) of the SRH, and Ultimate Segment
Decapsulation (USD) flavors defined in [RFC8986] either individually
or in combinations. The SRH processing of the End.NRP behavior with
PSP, USP, and USD is the same as [RFC8986].
This End.NRP SIDs can be allocated either by a centralized network
controller or by the network nodes, and the End.NRP behavior can be
announced using IGP or BGP-LS. The detailed protocol extension will
be described in a separate document.
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4. Use Cases for End.NRP behavior
This section describes possible procedures for the End.NRP behavior.
A group of End.NRP SIDs can be allocated for the set of network
resources associated with the SRv6 Policies, so that different
End.NRP SIDs can be used to steer service traffic into different set
of link resources (e.g. bandwidth, buffer and queue resources) in
packet forwarding.
Below is the possible procedures:
1. The controller get the topology information, calculate the SR
Policy path based on SLA.
2. The controller cooperates with the network nodes to complete
resource reservation and the End.NRP SID allocation along the SR
Policy path.
3. The controller use the End.NRP SID to build the SID list for the
explicit path.
4. Then the controller inform the headend the resource guaranteed
path by various means including: via BGP
[I-D.ietf-idr-segment-routing-te-policy], configuration or PCEP
[RFC8664] [I-D.ietf-pce-segment-routing-policy-cp].
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SRv6 Policy1 from PE1 to PE2
segment list <End.NRP11, End.NRP12, End.NRP13>
SRv6 Policy2 from PE1 to PE2
segment list <End.NRP21, End.NRP22, End.NRP23>
End.NRP12
End.NRP22
P1-----------P2
/ | |\
/ | | \
CE11------ End.NRP11 | |End.NRP13 ------ CE12
\ End.NRP21 | |End.NRP23 /
\ / | | \ /
PE1 \ | | PE2
/ \ | | / \
/ \ | | / \------ CE22
CE21------ \ | | /
\ | | /
P3------------P4
Figure 1
Figure 1 shows an example for the End.NRP behavior.
As shown in Figure 1, there are two customers with different leased
line requirements from PE1 to PE2:
leased line1 : 1G BandWidth with strict SLA guarantee.
leased line2 : 2G BandWidth with strict SLA guarantee.
Below is the possible procedures:
1. The controller get the topology information, calculate the SRv6
Policy 1 and SRv6 Policy 2 based on SLA.
2. The controller cooperates with the network nodes to complete
resource reservation and the End.NRP SID allocation along the
SRv6 Policy1 and SRv6 Policy 2. Taking the interface PE1-P1 of
SRv6 node PE1 along the SRv6 Policy 1 as an example, two
different NRPs(e.g. two dedicated queues) are partitioned from
the network resources of the physical link PE1-P1 (GE1/0/0). -
The NRP(Queue1:1G BW)of link PE1- P1 is reserved and associated
with End.NRP11 - The NRP(Queue2:2G BW)of link PE1- P1 is reserved
and associated with End.NRP21.
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3. The controller uses the End.NRP11, End.NRP12, and End.NRP13 to
build the SID list for the SRv6 Policy1 and use the End.NRP21,
End.NRP22, and End.NRP23 to build the SID list for the SRv6
Policy 2.
4. Then the controller inform the headend the segment list of SRv6
Policy 1 and the segment list of SRv6 Policy 2 by various means
including: via BGP [I-D.ietf-idr-segment-routing-te-policy],
configuration or PCEP [RFC8664]
[I-D.ietf-pce-segment-routing-policy-cp].
The traffic from customer1 and customer2 will be forwarded to PE2
through the NRPs previously reserved for each hop link on the path of
SRv6 Policy1 and SRv6 Policy2 respectively, thus Customer 1 and
Customer 2 are provided with end-to-end 1G bandwidth resources and 2G
bandwidth resources respectively, and leased line services are
guaranteed by strict SLAs.
5. Acknowledgements
TBD.
6. IANA Considerations
The document defines a new SRv6 Endpoint behavior called End.NRP.
This I-D requests the IANA to allocate, within the "SRv6 Endpoint
Behaviors" sub-registry belonging to the top-level "Segment-routing
with IPv6 dataplane (SRv6) Parameters" registry, the following
allocations:
Value Endpoint Behavior Reference
---------------------------------------------------------------
TBD1 End.NRP [This.ID]
7. Security Considerations
TBD.
8. Normative References
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[I-D.ietf-idr-segment-routing-te-policy]
Previdi, S., Filsfils, C., Talaulikar, K., Mattes, P.,
Jain, D., and S. Lin, "Advertising Segment Routing
Policies in BGP", Work in Progress, Internet-Draft, draft-
ietf-idr-segment-routing-te-policy-20, 27 July 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-idr-
segment-routing-te-policy-20>.
[I-D.ietf-pce-segment-routing-policy-cp]
Koldychev, M., Sivabalan, S., Barth, C., Peng, S., and H.
Bidgoli, "PCEP extension to support Segment Routing Policy
Candidate Paths", Work in Progress, Internet-Draft, draft-
ietf-pce-segment-routing-policy-cp-08, 24 October 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-pce-
segment-routing-policy-cp-08>.
[I-D.ietf-spring-resource-aware-segments]
Dong, J., Bryant, S., Miyasaka, T., Zhu, Y., Qin, F., Li,
Z., and F. Clad, "Introducing Resource Awareness to SR
Segments", Work in Progress, Internet-Draft, draft-ietf-
spring-resource-aware-segments-06, 11 October 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-spring-
resource-aware-segments-06>.
[I-D.ietf-teas-ietf-network-slices]
Farrel, A., Drake, J., Rokui, R., Homma, S., Makhijani,
K., Contreras, L. M., and J. Tantsura, "A Framework for
IETF Network Slices", Work in Progress, Internet-Draft,
draft-ietf-teas-ietf-network-slices-19, 21 January 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-teas-
ietf-network-slices-19>.
[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>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/info/rfc8402>.
[RFC8664] Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W.,
and J. Hardwick, "Path Computation Element Communication
Protocol (PCEP) Extensions for Segment Routing", RFC 8664,
DOI 10.17487/RFC8664, December 2019,
<https://www.rfc-editor.org/info/rfc8664>.
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[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
Weiqiang Cheng
China Mobile
China
Email: chengweiqiang@chinamobile.com
Wenying Jiang
China Mobile
China
Email: jiangwenying@chinamobile.com
Ran Chen
ZTE Corporation
Nanjing
China
Email: chen.ran@zte.com.cn
Detao Zhao
ZTE Corporation
Nanjing
China
Email: zhao.detao@zte.com.cn
Changwang Lin
New H3C Technologies
China
Email: linchangwang.04414@h3c.com
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