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Fixing the issue in RFC2370 by proposing a solution to validate AS-scope Opaque LSAs received outside of the LSA originator area, using the mechanism for validation of AS external route LSAs.
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AS-scope (type 11) Opaque LSA Validation(draft-bryskin-ospf-lsa-type11-validation-00.txt) Igor Bryskin (Movaz Networks) : ibryskin@movaz.com Alex Zinin (Alcatel) : zinin@psg.com Lou Berger (LabN Consulting, LLC) : lberger@labn.net
Purpose of the document • Fix issue in RFC2370 • There is no way to validate AS-scope (type 11) Opaque LSAs received outside of the LSA originator area • Proposed solution reuses the mechanism for validation of AS external route (type 5) LSAs
The Problem • [RFC2370] introduces a mechanism for the distribution of application specific information using the OSPF protocol via opaque LSAs. The distribution of opaque LSA could be limited to: • only immediate neighbors of the originator (LSAs type-9) • only OSPF nodes located within the originator's OSPF area (LSAs type-10) • all OSPF nodes within the originator's OSPF domain/AS (LSAs type-11) • There is no way for OSPF nodes in remote areas to check availability of a type -11 LSA originator • As there is with AS external route (type-5)
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
Proposed Solution • Apply the same approach used for validation of AS external route (type-5) LSAs as used to validate AS-scope (type-11) opaque LSAs • Some details: • AS-scope opaque LSAs originators must act as ASBRs • To trigger ASBR-summary (type-4) LSAs originated by ABRs (without ABR modification) • Uses current E-bit • Set by OSPF nodes that originate AS-scope opaque LSAs • In the Options field of Hello packets and LSAs • Node validate received AS-scope (type-11) opaque LSAs via type-4 LSAs • As with type-5 LSAs, type-11 LSAs only processed if advertising router (ASBR) has a routing table entry
None Backward Compatibility issues
The suggested solution reuses the ASBR tracking mechanism that is already employed in basic OSPF for type-5 LSAs. Applying it to type-11 Opaque LSAs does not create any threats that are not already known for type-5 LSAs . Security Considerations
Type-11 Opaque LSAs flooding rules are unchanged The suggested solution does not apply for stub-areas We propose to make this draft a WG document Notes/Next Steps