Dear Spring WG I have a ? related to the bottom of section 5 about how BSID label can be used for compression of the label stack.
My understanding of BSID AFAIK is that the BSID can be static value or auto generated value by the SR source node and is used to bind the candidate path to the forwarding plane at which time the BSID is popped off the label stack and the segment list specified by the BSID is pushed onto the packet or SRV6 SRH or uSID carrier. I am not aware that BSID can be used as a topological sid and is just locally significant however the advertised with the VPN overlay BGP prefix as informational only is my understanding. If that is true I guess since the BSID contains the entire instruction set for steering why not always use the BSID label and not the typical prefix sid and adj sid label when steering. That would cut way down on MSD down to a single label. “In the SPRING architecture, Node SIDs or Binding SIDs can be used to reduce the label stack size. As an example, to steer the traffic on the same path as before, PE1 could use the following label stack: <Node_P9, Node_P5, Binding_P5, Node_PE2>. In this example, we consider a combination of Node SIDs and a Binding SID advertised by P5 that will stitch the traffic along the path P10 -> P11 -> P12 -> P13. The instruction associated with the Binding SID at P5 is thus to swap Binding_P5 to Adj_P12-P13 and then push <Adj_P11-P12, Node_P11>. P5 acts as a stitching node that pushes additional labels on an existing label stack; P5's MSD needs also to be taken into account and may limit the number of labels that can be imposed.” Question about adjacency set sid ? 7.2.2.2. <https://datatracker.ietf.org/doc/html/rfc8662#section-7.2.2.2>Adjacency-Set SID <https://datatracker.ietf.org/doc/html/rfc8662#name-adjacency-set-sid> An adjacency-set is an Adj-SID that refers to a set of adjacencies. When an adjacency-set segment is used within a label stack, an implementation can deduce that load-balancing is expected at the node that advertised this adjacency segment. An implementation MAY favor the insertion of an ELI/EL after the Adj-SID representing an adjacency-set.¶ <https://datatracker.ietf.org/doc/html/rfc8662#section-7.2.2.2-1> I don’t see any other SR document that talks about adjacency set sid. Is this set sid part of the base SR architecture and as well is another topological sid I don’t see defined anywhere? Thank you <http://www.verizon.com/> *Gyan Mishra* *Network Solutions A**rchitect * *Email gyan.s.mis...@verizon.com <gyan.s.mis...@verizon.com>* *M 301 502-1347*
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