Re: [OSPF] draft-psenak-ospf-segment-routing-extensions-05

"Anil Kumar S N (VRP Network BL)" <> Tue, 22 September 2015 06:43 UTC

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From: "Anil Kumar S N (VRP Network BL)" <>
To: Peter Psenak <>, "" <>, "" <>, "" <>, "" <>, "" <>, Jeff Tantsura <>, "" <>
Thread-Topic: draft-psenak-ospf-segment-routing-extensions-05
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Date: Tue, 22 Sep 2015 06:43:39 +0000
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Subject: Re: [OSPF] draft-psenak-ospf-segment-routing-extensions-05
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Hi Authors,

In Section : 2 4.2.  Prefix SID Sub-TLV, L-Flag represent IGP segment is local or global (Suggest to change to G so that it will be consistent with Segment Routing Architecture draft) similar to that can we have A-Flag to indicate Anycast SID.

The L-Flag: Local/Global Flag.  If set, then the value/index
         carried by the PrefixSID has local significance.  If not set,
         then the value/index carried by this subTLV has global
3.2<>.2>.  IGP Segment Terminology
3.2.1<>.1>.  IGP Segment, IGP SID
   The terms "IGP Segment" and "IGP SID" are the generic names for a
   segment attached to a piece of information advertised by a link-state
   IGP, e.g. an IGP prefix or an IGP adjacency.

   The IGP signaling extension to advertise an IGP segment includes the
   G-Flag indicating whether the IGP segment is global or local.
                                      /   |   \
                             Prefix-SID   x   Adj-SID
                            /     |    \
                      Node-SID    y   Anycast-SID

                       Figure 7: IGP SID Terminology

   The IGP Segment terminology is introduced to ease the documentation
   of SR use-cases and hence does not propose a name for any possible
   variation of IGP segment supported by the architecture.  For example,
   y in Figure 7 could represent a local IGP segment attached to an IGP
   Prefix.  This variation, while supported by the SR architecture is
   not seen in the SR use-cases and hence does not receive a specific

Thanks & Regards
Anil S N

"Be liberal in what you accept, and conservative in what you send" - Jon Postel

From: Anil Kumar S N (VRP Network BL)
Sent: 21 September 2015 20:00
To: 'Peter Psenak'; ''com'; ''com'; ''net'; ''com'; ''com'; Jeff Tantsura
Cc: OSPF WG List
Subject: draft-psenak-ospf-segment-routing-extensions-05

Hi Authors,

In Segment Routing Architecture draft,  There is a provision to allocate multiple Adj-SIDs to same adjacency in case of bundle interface.
In IGP extension draft we need to have one more Adj-SID Sub-TLV type to distribute SID's for bundle members with bundle member ID along with link type/data & ID.

Please let me know your opinion.

Reference :

3.5.  IGP-Adjacency Segment, Adj-SID

A node MAY allocate multiple Adj-SIDs to the same adjacency.  An
   example is where the adjacency is established over a bundle
   interface.  Each bundle member MAY have its own Adj-SID.

Thanks & Regards
Anil S N

"Be liberal in what you accept, and conservative in what you send" - Jon Postel