draft-ietf-ospf-segment-routing-msd-03.txt   draft-ietf-ospf-segment-routing-msd-04.txt 
skipping to change at page 1, line 14 skipping to change at page 1, line 14
Internet-Draft Individual Internet-Draft Individual
Intended status: Standards Track U. Chunduri Intended status: Standards Track U. Chunduri
Expires: September 29, 2017 Huawei Technologies Expires: September 29, 2017 Huawei Technologies
S. Aldrin S. Aldrin
Google, Inc Google, Inc
P. Psenak P. Psenak
Cisco Systems Cisco Systems
March 28, 2017 March 28, 2017
Signaling MSD (Maximum SID Depth) using OSPF Signaling MSD (Maximum SID Depth) using OSPF
draft-ietf-ospf-segment-routing-msd-03 draft-ietf-ospf-segment-routing-msd-04
Abstract Abstract
This document proposes a way to signal Maximum SID Depth (MSD) This document proposes a way to signal Maximum SID Depth (MSD)
supported by a node at node and/or link granularity by an OSPF supported by a node at node and/or link granularity by an OSPF
Router. In a Segment Routing (SR) enabled network a centralized Router. In a Segment Routing (SR) enabled network a centralized
controller that programs SR tunnels needs to know the MSD supported controller that programs SR tunnels needs to know the MSD supported
by the head-end at node and/or link granularity to push the SID stack by the head-end at node and/or link granularity to push the SID stack
of an appropriate depth. MSD is relevant to the head-end of a SR of an appropriate depth. MSD is relevant to the head-end of a SR
tunnel or Binding-SID anchor node where Binding-SID expansions might tunnel or Binding-SID anchor node where Binding-SID expansions might
skipping to change at page 3, line 14 skipping to change at page 3, line 14
necessarily act as head-ends. In order, for BGP-LS to signal MSD for necessarily act as head-ends. In order, for BGP-LS to signal MSD for
the all nodes and links in the network MSD is relevant, MSD the all nodes and links in the network MSD is relevant, MSD
capabilites SHOULD be distributed to every OSPF router in the capabilites SHOULD be distributed to every OSPF router in the
network. network.
[I-D.ietf-ospf-mpls-elc] defines Readable Label Depth Capability [I-D.ietf-ospf-mpls-elc] defines Readable Label Depth Capability
(RLDC) that is used by a head-end to insert Entropy Label (EL) at (RLDC) that is used by a head-end to insert Entropy Label (EL) at
appropriate depth, so it could be read by transit nodes. MSD in appropriate depth, so it could be read by transit nodes. MSD in
contrary signals ability to push SID's stack of a particular depth. contrary signals ability to push SID's stack of a particular depth.
MSD of type 1 (IANA Registry) is used to signal the total number of MSD of type 1 (IANA Registry), called Base MSD is used to signal the
SIDs a node is capable of imposing, to be used by a path computation total number of SIDs a node is capable of imposing, to be used by a
element/controller. In case, there are additional labels (e.g. path computation element/controller. In case, there are additional
service) that are to be pushed to the stack - this would be signaled labels (e.g. service) that are to be pushed to the stack - this would
with an another MSD type (TBD), MSD SHOULD be adjusted to reflect be signaled with an another MSD type (TBD), MSD SHOULD be adjusted to
that. In the future, new MSD types could be defined to signal reflect that. In the future, new MSD types could be defined to
additional capabilities: entropy labels, labels that can be pushed signal additional capabilities: entropy labels, labels that can be
thru recirculation, or another dataplane e.g IPv6. pushed thru recirculation, or another dataplane e.g IPv6.
1.1. Conventions used in this document 1.1. Conventions used in this document
1.1.1. Terminology 1.1.1. Terminology
BGP-LS: Distribution of Link-State and TE Information using Border BGP-LS: Distribution of Link-State and TE Information using Border
Gateway Protocol Gateway Protocol
OSPF: Open Shortest Path First OSPF: Open Shortest Path First
skipping to change at page 6, line 21 skipping to change at page 6, line 21
proposed in Section 4 from OSPFv2 Extended Link Opaque LSAs Extended proposed in Section 4 from OSPFv2 Extended Link Opaque LSAs Extended
Link TLV registry and from Router-Link TLV defined in OSPFv3 Extend- Link TLV registry and from Router-Link TLV defined in OSPFv3 Extend-
LSA Sub-TLV registry. LSA Sub-TLV registry.
This document also request IANA to create a new Sub-type registry as This document also request IANA to create a new Sub-type registry as
proposed in Section 3, Section 4. proposed in Section 3, Section 4.
Value Name Reference Value Name Reference
----- --------------------- ------------- ----- --------------------- -------------
0 Reserved This document 0 Reserved This document
1 MSD This document 1 Base MSD This document
2-250 Unassigned This document 2-250 Unassigned This document
251-254 Experimental This document 251-254 Experimental This document
255 Reserved This document 255 Reserved This document
Figure 3: MSD Sub-type Codepoints Registry Figure 3: MSD Sub-type Codepoints Registry
7. Security Considerations 7. Security Considerations
This document describes a mechanism to signal Segment Routing MSD This document describes a mechanism to signal Segment Routing MSD
supported at node and/or link granularity through OSPF LSA's and does supported at node and/or link granularity through OSPF LSA's and does
 End of changes. 3 change blocks. 
10 lines changed or deleted 10 lines changed or added

This html diff was produced by rfcdiff 1.45. The latest version is available from http://tools.ietf.org/tools/rfcdiff/