draft-ietf-mpls-sr-over-ip-05.txt   draft-ietf-mpls-sr-over-ip-06.txt 
Network Working Group X. Xu Network Working Group X. Xu
Internet-Draft Alibaba, Inc Internet-Draft Alibaba, Inc
Intended status: Standards Track S. Bryant Intended status: Standards Track S. Bryant
Expires: November 11, 2019 Huawei Expires: November 24, 2019 Huawei
A. Farrel A. Farrel
Old Dog Consulting Old Dog Consulting
S. Hassan S. Hassan
Cisco Cisco
W. Henderickx W. Henderickx
Nokia Nokia
Z. Li Z. Li
Huawei Huawei
May 10, 2019 May 23, 2019
SR-MPLS over IP SR-MPLS over IP
draft-ietf-mpls-sr-over-ip-05 draft-ietf-mpls-sr-over-ip-06
Abstract Abstract
MPLS Segment Routing (SR-MPLS) is an MPLS data plane-based source MPLS Segment Routing (SR-MPLS) is an MPLS data plane-based source
routing paradigm in which the sender of a packet is allowed to routing paradigm in which the sender of a packet is allowed to
partially or completely specify the route the packet takes through partially or completely specify the route the packet takes through
the network by imposing stacked MPLS labels on the packet. SR-MPLS the network by imposing stacked MPLS labels on the packet. SR-MPLS
can be leveraged to realize a source routing mechanism across MPLS, can be leveraged to realize a source routing mechanism across MPLS,
IPv4, and IPv6 data planes by using an MPLS label stack as a source IPv4, and IPv6 data planes by using an MPLS label stack as a source
routing instruction set while making no changes to SR-MPLS routing instruction set while making no changes to SR-MPLS
skipping to change at page 2, line 4 skipping to change at page 2, line 4
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on November 11, 2019. This Internet-Draft will expire on November 24, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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capitals, as shown here. capitals, as shown here.
2. Use Cases 2. Use Cases
Tunneling SR-MPLS using IPv4 and/or IPv6 tunnels is useful at least Tunneling SR-MPLS using IPv4 and/or IPv6 tunnels is useful at least
in the use cases listed below. In all cases, this can be enabled in the use cases listed below. In all cases, this can be enabled
using an IP tunneling mechanism such as MPLS-in-UDP as described in using an IP tunneling mechanism such as MPLS-in-UDP as described in
[RFC7510]. The tunnel selected MUST have its remote end point [RFC7510]. The tunnel selected MUST have its remote end point
(destination) address equal to the address of the next SR-MPLS (destination) address equal to the address of the next SR-MPLS
capable node identified as being on the SR path (i.e., the egress of capable node identified as being on the SR path (i.e., the egress of
the active node segment). The local end point (source) address is the active segment). The local end point (source) address is set to
set to an address of the encapsulating node. [RFC7510] gives further an address of the encapsulating node. [RFC7510] gives further advice
advice on how to set the source address if the UDP zero-checksum mode on how to set the source address if the UDP zero-checksum mode is
is used with MPLS-in-UDP. used with MPLS-in-UDP.
o Incremental deployment of the SR-MPLS technology may be o Incremental deployment of the SR-MPLS technology may be
facilitated by tunneling SR-MPLS packets across parts of a network facilitated by tunneling SR-MPLS packets across parts of a network
that are not SR-MPLS as shown in Figure 1. This demonstrates how that are not SR-MPLS as shown in Figure 1. This demonstrates how
islands of SR-MPLS may be connected across a legacy network. It islands of SR-MPLS may be connected across a legacy network. It
may be particularly useful for joining sites (such as data may be particularly useful for joining sites (such as data
centers). centers).
________________________ ________________________
_______ ( ) _______ _______ ( ) _______
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Global Block (SRGB). The SRGB is defined in [RFC8402]. There are Global Block (SRGB). The SRGB is defined in [RFC8402]. There are
a number of ways that the advertisement can be achieved including a number of ways that the advertisement can be achieved including
IGPs, BGP, configuration/management protocols. For example, see IGPs, BGP, configuration/management protocols. For example, see
[I-D.ietf-bess-datacenter-gateway]. [I-D.ietf-bess-datacenter-gateway].
o When Router E advertises the prefix-SID SID(E) of prefix P(E) it o When Router E advertises the prefix-SID SID(E) of prefix P(E) it
MUST also advertise the encapsulation endpoint and the tunnel type MUST also advertise the encapsulation endpoint and the tunnel type
of any tunnel used to reach E. This information is flooded domain of any tunnel used to reach E. This information is flooded domain
wide. wide.
o If A and E are in different IGP domains then the information MUST o If A and E are in different routing domains then the information
be flooded into both domains. How this is achieved depends on the MUST be flooded into both domains. How this is achieved depends
advertisement mechanism being used. The objective is that router on the advertisement mechanism being used. The objective is that
A knows the characteristics of router E that originated the router A knows the characteristics of router E that originated the
advertisement of SID(E). advertisement of SID(E).
o Router A programs the FIB entry for prefix P(E) corresponding to o Router A programs the FIB entry for prefix P(E) corresponding to
the SID(E) according to whether a pop or swap action is advertised the SID(E) according to whether a pop or swap action is advertised
for the prefix. The resulting action may be: for the prefix. The resulting action may be:
* pop the top label * pop the top label
* swap the top label to a value equal to SID(E) plus the lower * swap the top label to a value equal to SID(E) plus the lower
bound of the SRGB of E bound of the SRGB of E
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May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/info/rfc8402>. July 2018, <https://www.rfc-editor.org/info/rfc8402>.
8.2. Informative References 8.2. Informative References
[I-D.ietf-6man-segment-routing-header] [I-D.ietf-6man-segment-routing-header]
Filsfils, C., Previdi, S., Leddy, J., Matsushima, S., and Filsfils, C., Dukes, D., Previdi, S., Leddy, J.,
d. daniel.voyer@bell.ca, "IPv6 Segment Routing Header Matsushima, S., and d. daniel.voyer@bell.ca, "IPv6 Segment
(SRH)", draft-ietf-6man-segment-routing-header-18 (work in Routing Header (SRH)", draft-ietf-6man-segment-routing-
progress), April 2019. header-19 (work in progress), May 2019.
[I-D.ietf-bess-datacenter-gateway] [I-D.ietf-bess-datacenter-gateway]
Farrel, A., Drake, J., Rosen, E., Patel, K., and L. Jalil, Farrel, A., Drake, J., Rosen, E., Patel, K., and L. Jalil,
"Gateway Auto-Discovery and Route Advertisement for "Gateway Auto-Discovery and Route Advertisement for
Segment Routing Enabled Domain Interconnection", draft- Segment Routing Enabled Domain Interconnection", draft-
ietf-bess-datacenter-gateway-02 (work in progress), ietf-bess-datacenter-gateway-02 (work in progress),
February 2019. February 2019.
[I-D.ietf-isis-encapsulation-cap] [I-D.ietf-isis-encapsulation-cap]
Xu, X., Decraene, B., Raszuk, R., Chunduri, U., Contreras, Xu, X., Decraene, B., Raszuk, R., Chunduri, U., Contreras,
L., and L. Jalil, "Advertising Tunnelling Capability in L., and L. Jalil, "Advertising Tunnelling Capability in
IS-IS", draft-ietf-isis-encapsulation-cap-01 (work in IS-IS", draft-ietf-isis-encapsulation-cap-01 (work in
progress), April 2017. progress), April 2017.
[I-D.ietf-isis-segment-routing-extensions] [I-D.ietf-isis-segment-routing-extensions]
Previdi, S., Ginsberg, L., Filsfils, C., Bashandy, A., Previdi, S., Ginsberg, L., Filsfils, C., Bashandy, A.,
Gredler, H., and B. Decraene, "IS-IS Extensions for Gredler, H., and B. Decraene, "IS-IS Extensions for
Segment Routing", draft-ietf-isis-segment-routing- Segment Routing", draft-ietf-isis-segment-routing-
extensions-24 (work in progress), April 2019. extensions-25 (work in progress), May 2019.
[I-D.ietf-mpls-spring-entropy-label] [I-D.ietf-mpls-spring-entropy-label]
Kini, S., Kompella, K., Sivabalan, S., Litkowski, S., Kini, S., Kompella, K., Sivabalan, S., Litkowski, S.,
Shakir, R., and J. Tantsura, "Entropy label for SPRING Shakir, R., and J. Tantsura, "Entropy label for SPRING
tunnels", draft-ietf-mpls-spring-entropy-label-12 (work in tunnels", draft-ietf-mpls-spring-entropy-label-12 (work in
progress), July 2018. progress), July 2018.
[I-D.ietf-ospf-encapsulation-cap] [I-D.ietf-ospf-encapsulation-cap]
Xu, X., Decraene, B., Raszuk, R., Contreras, L., and L. Xu, X., Decraene, B., Raszuk, R., Contreras, L., and L.
Jalil, "The Tunnel Encapsulations OSPF Router Jalil, "The Tunnel Encapsulations OSPF Router
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