Update to:Update to:The OSPF Opaque LSA Option The OSPF Opaque LSA Option

draft-berger-ospf-rfc2370bis draft-berger-ospf-rfc2370bis

Lou Berger (lberger@labn.net)Lou Berger (lberger@labn.net)Igor Bryskin (ibryskin@advaoptical.com)Igor Bryskin (ibryskin@advaoptical.com)

Alex Zinin (zinin@psg.com)Alex Zinin (zinin@psg.com)Original Author: Rob ColtunOriginal Author: Rob Coltun

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Draft Background

• There is no way for OSPF routers to validate OSPF AS-scope (type 11) Opaque LSAs received outside of the LSA originator’s area– Issue presented / addressed in

draft-bryskin-ospf-lsa-type11-validation

• Presented at last IETF OSPF WG• Conclusion from last WG meeting:

Rev RFC2370

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Changes In Draft From RFC2370

• Updated draft format• Adopted RFC2119 terminology

– Key words "MUST", "MUST NOT", "REQUIRED", …– Requires WG review – no issues expected

• Added “Routers processing opaque LSAs MAY choose to give priority to processing base OSPF LSA types over opaque LSA types.”

• Added reference to draft-ietf-ospf-mib-update-• Added Inter-Area Considerations

– From draft-bryskin-ospf-lsa-type11-validation• Removed reference to expired drafts

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Inter-Area Solution

As presented at last IETF:• Parallels and reuses the mechanism for

validation of OSPF type 5 LSAs• Validation of type-5 LSAs

– AS external route (type-5) LSAs have also the AS-scope, hence there is a similar problem with their validation

– The problem is addressed via use of area-scope ASBR-summary (type-4) LSAs originated by ABRs for every known ASBR

– The validation of AS-scope (type-11) opaque LSAs could be achieved if ABRs treat their originators as ASBRs

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Inter-Area Solution (cont)

• LSA origination changes– Routers that originate AS-scope opaque LSAs also set the E-bit

in the Options field of originated OSPF Hello packets– Such Routers also set the E-bit in the Options field of the header

of each LSA it injects into the network

• LSA validation changes– Router MUST look up the routing table for the ASBR with the

Router ID matching the Advertising Router ID found in the received LSA header.

– If no entries could be found (i.e., ASBR is unreachable), the router ignores the LSA.

– A router MUST discontinue using ALL Opaque LSAs originated by a router that is identified as being unreachable

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Next Steps

• WG Feedback– Review of RFC2119 terminology– Any other changes needed?

• • •

• Adoption as WG document

Thank YouThank You