Minutes IETF100: isis
IS-IS for IP Internets
||Minutes IETF100: isis
IS-IS/OSPF WG Agenda IETF-100
Time Slot (150m): Thursday, November 16, 2017 09:30-12:00 (GMT+8)
Scribe: Ayan Banerjee (ayabaner)
* Intro, Adminastriva, Document Status
o Presenter: IS-IS Chairs and OSPF
Chairs (Acee Lindem
, Abhay Roy ,
Christian Hopps , Hannes Gredler
Discussion of merging WGs:
Chris Hopps: Let's discuss merging the two WGs.
Acee: Initially against merger but now doesn't feel it is that bad due to
advances in OSPFv3 TLV encoding and OSPFv2 prefix/link attributes. Chris
Bowers: Thinks having IS-IS and OSPF together will have long-term benefits.
Chris Bowers: June changes removed ERO and binding SID. Binding SID is
needed. Jeff Tantsura: What about OSPF? Alia Atlas: ERO was not specified
and didn't relate to SPRING working documents. Behavior and archiecture were
not specified. Chris Hopps: Are we aligned? Jeff Tantsura: What is Chris
worried about? Chris Hopps: The SR Binding TLV is needed to support context
mirroring which is implmented. Jeff Tantsura: Binding SID could be published
with use cases. Ketan Talaulikar: Whatever usage of ERO is removed so
binding SID could also be removed. Shraddha Hedge: The binding SID TLVs are
not implemented right now. There is a use case that could be added in a
separate draft. Acee: Usage of Binding SID for context mirroring is
sub-optimal. If required, we will define an OSPF Sub-TLV and SID for this
Alia Atlas: OSPFv2 Segment Routing will be sent to the IESG with other
Chris Hopps: Is IS-IS YANG model in sync with OSPF?
Acee: Some updates needed - will discuss with co-authors.
* OSPF Graceful Restart Enhancements
o Presenter: Acee Lindem
Shraddha Hedge: If you generalize the first, you need to handle the case
where the peer router is slow forming an adjacency. Acee: Could defer
convergence if any neighbors are in Exchange or greater state.
* OSPF LLS Extensions for Local Interface ID Advertisement
o Presenter: Ketan Jivan Talaulikar
Acee Lindem: Does anybody have any reservations to requesting early IANA
allocation for this draft?
No objections in the room.
* ISIS Segment Routing Flexible Algorithm
o Presenter: Shraddha Hedge
Chris Hopps: Why are user defined algorithms needed?
Shraddha: Constraints cannot be standardized.
Dhruv Dhody: PCE has object types for metric types. Maybe metric types in
PCE could be used. Ville Hallivuori: One algorithm conflict disable an
algorith in the domain? Shraddha: If there is a chance of looping, you must
revert to default behavior. Chris Hopps: This a misconfiguration and we
don't need to optimize. Bruno: In theory, you need topology ID as well.
With SR, we have two algorithms and these cannot be redefined. Shraddha: We
don't use standard algorithms for user defined. Metric types are also
standardized. Bruno: Standardized algorithm with user defined metric?
Shraddha: If you have an algorithm that needs to be standarized, can go to
IANA. Ketan: It is possible to define strict SPF with TE metric type.
Stephane: This is not an algorithm, it is contraints for SPF. Shraddha:
There are Sub-TLVs with contraints. Stephane: Constraints can be
independent of algorithms. Shraddha: We will look at decoupling the
algorthm and constraint specifications. Chris: MRT algorithms could be
defined as standard algorithms. Constraints can be used with standard
algorthims. Bruno: Could add standard algorithm field to existing TLVs.
Stephane: Maybe could be made flexible by reusing TE objects. Acee: Need to
handle case where multi-homed prefix is advertised with different
algorithms by different routers. Acee: IPR exists on draft. Dhruv: Please
push IPR declaration to the Working Group.
* IS-IS TE Attributes per application
o Presenter: Acee Lindem for Les Ginsberg
o Document: https://datatracker.ietf.org/doc/draft-ietf-isis-te-app/
Chris Bowers: Flex Algorithm should not be referenced since it is not a WG
document. Chris Bowers: There are differences between explicit and implicit
* Enablement Discussion
Chris Hopps goes through history of draft and his perspective on the
adoption of the enablement draft.
Chris Hopps: Will discuss enablement in next topic.
Chris Hopps: Do we need explicit enablement decoupled from attribute
advertisement? Acee: It is dependent on algorithm. For all but TE, it is
clear that it is not necessary. Chris Bowers: With both documents WG
documents, it is a difficult question. I see need for enablement draft.
Solves immediate problem. Alia Atlas: How does enablement related to TEAS
and GMPLS? Ketan: Application specific values is a problem that we need to
solve. Shraddha: There are sometimes different solutions to the same problem
in IETF. Chris Bowers: WG adopted IS-IS TE attributes draft didn't address
enablement. Could adopt both drafts. Bruno: Application specific information
is theoretical. Stephane: Application specific attributes could be complex.
Chris Hopps: It is not that complex that it can't be implmented. Chris
Bowers: Could be deployment complexities. Chris Hopps: We are not going to
decide this today. Acee: There are much bigger issues in OSPF than IS-IS
with the number of LSAs required for non-TE applications. In the case of
OSPF, this is more important than how TE enablement is handled.
* More Merging Workgroups
Alia Atlas: Polling of who would only attend OSPF or IS-IS but not both>
Name for New WG:
LSR - Link State Routing
IGP-LS - IGP - Link State
LaSeR - Link State Routing