SPRING Working Group W. Cheng
Internet Draft W. Jiang
Intended status: Standards Track China Mobile
Expires: January 13, 2023 R. Chen
D. Zhao
ZTE Corporation
C. Lin
New H3C Technologies
July 12, 2022
Network Resource Programming with SRv6
draft-cheng-spring-srv6-resource-programming-00
Abstract
This document defines a new SRv6 network function which can be used
for SRv6 Network Resource Programming. A new SRv6 Endpoint behavior
is used to associate with a set of network resource partition,
called End.NRP. By using the End.NRP SID , the SRv6 policy can
provide the capability of network resources programming.
Status of this Memo
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Table of Contents
1. Introduction ................................................ 2
1.1. Requirements Language .................................. 3
2. End.NRP Behavior ............................................ 3
3. Use Cases for End.NRP behavior .............................. 4
4. Acknowledgements ............................................ 6
5. IANA Considerations ......................................... 6
6. Security Considerations ..................................... 6
7. References .................................................. 6
7.1. 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.
[I-D.ietf-teas-ns-ip-mpls] introduces a Slice-Flow Aggregate as the
collection of packets (from one or more IETF network slice traffic
streams) that match an NRP Policy selection criterion and are
offered the same forwarding treatment. The NRP Policy is used to
realize an NRP by instantiating specific control and data plane
resources on select topological elements in an IP/MPLS network.
Segment Routing (SR) [RFC8402] leverages the source routing
paradigm. An ingress node steers a packet through an ordered list of
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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. Network Programming
combines Segment Routing functions, both simple and complex, to
achieve a networking objective that goes beyond mere packet routing.
When SRv6 network provides network slicing service, 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'). Typical types of the network resources
include link bandwidth, buffers, and queues.
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 ), called End.NRP. By using
the End.NRP SID to program the path of the SRv6 policy, it enables
the SRv6 network resources programming.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. End.NRP Behavior
This section 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), called End.NRP. The End.NRP
is a variant of the End.X behavior defined in [RFC8986].
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. forward the packet via the NRP (e.g. bandwidth, buffer and
queue resources) of the outbound interface associated with the SID S
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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.
3. 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 are the possible procedures:
1. The controller gets 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 uses the End.NRP SID to build the SID list for the
explicit path.
4. Then the controller informs 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].
SRv6 Policy1 from R1 to R4
Segment list <End.NRP11, End.NRP12, End.NRP13>
SRv6 Policy2 from R1 to R4
Segment list <End.NRP21, End.NRP22, End.NRP23>
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+-----+ +-----+ +-----+ +-----+
| R1 |------------| R2 |-------------| R3 |-------------| R4 |
+-----+ +-----+ +-----+ +-----+
End.NRP11 End.NRP12 End.NRP13
BW:1G BW:1G BW:1G
NRP-ID 100 NRP-ID 100 NRP-ID 100
End.NRP21 End.NRP22 End.NRP23
BW:2G BW:2G BW:2G
NRP-ID 200 NRP-ID 200 NRP-ID 200
Figure 1
Figure 1 shows an example for the End.NRP behavior.
As shown in Figure 1, there are two network resource partitions:
NRP-ID 100 and NRP-ID 200, allocated to two network slices.The
End.NRP SID can be associated with the set of network resources
partitions allocated to the slice/slice aggregate. Thus a End.NRP
SID can be used to build SR Policy, and the transit node can steer
traffic into the set of network resources allocated to the slice.
Below are the possible procedures:
1. The controller gets 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 R1-R2 of SRv6 node
R1 along the SRv6 Policy 1 as an example, End.NRP11 is associated
with NRP-ID 100, which is the network resource partition Identifier
for the qos queue of BW 1G, and End.NRP21 is associated with NRP-ID
200 which is the network resource partition Identifier for the qos
queue of BW 2G.
3. The controller use 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],
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configuration or PCEP [RFC8664] [I-D.ietf-pce-segment-routing-
policy-cp].
4. Acknowledgements
TBD.
5. IANA Considerations
This document has no IANA actions.
6. Security Considerations
TBD.
7. References
7.1. Normative References
[I-D.bestbar-lsr-spring-nrp] Saad, T., Beeram, V. P., Chen, R.,
Peng, S., Wen, B., and D. Ceccarelli, "IGP Extensions for
SR Network Resource Partition SIDs", Work in Progress,
Internet-Draft, draft-bestbar-lsr-spring-nrp-00, 11
January 2022,<https://datatracker.ietf.org/doc/html/draft-
bestbar-lsr-spring-nrp-00>.
[I-D.chen-idr-bgp-ls-transport-slice]Chen, R., Peng, S., Saad, T.,
and V. P. Beeram, "BGP-LS Extensions for Network Resource
Partition identifier", Work in Progress, Internet-Draft,
draft-chen-idr-bgp-ls-transport-slice-04, 27 December
2021, <https://datatracker.ietf.org/doc/html/draft-chen-
idr-bgp-ls-transport-slice-04>.
[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-18, 16 June 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-idr-
segment-routing-te-policy-18>.
[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-07, 21 April 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-pce-
segment-routing-policy-cp-07>.
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[I-D.ietf-teas-ietf-network-slices]Farrel, A., Drake, J., Rokui, R.,
Homma, S., Makhijani, K., Contreras, L. M., and J.
Tantsura, "Framework for IETF Network Slices", Work in
Progress, Internet-Draft, draft-ietf-teas-ietf-network-
slices-12, 30 June 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-teas-
ietf-network-slices-12>.
[I-D.ietf-teas-ns-ip-mpls]Saad, T., Beeram, V. P., Dong, J., Wen,
B., Ceccarelli, D., Halpern, J., Peng, S., Chen, R., Liu,
X., Contreras, L. M., Rokui, R., and L. Jalil, "Realizing
Network Slices in IP/MPLS Networks", Work in Progress,
Internet-Draft, draft-ietf-teas-ns-ip-mpls-00, 16 June
2022, <https://datatracker.ietf.org/doc/html/draft-ietf-
teas-ns-ip-mpls-00>.
[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>.
[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>.
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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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