The IA flag in the OSPF Extended Prefix Range TLV does not indicate that the prefix-SID mapping advertised via it is for use for only intra or inter area prefixes. The mappings can be used for assignment of SIDs for ALL types of OSPF prefixes - regardless of the IA bit.
The IA flag is only to prevent looping during flooding of area-scoped LSAs with OSPF Extended Prefix Range TLVs when they are propagated across areas. When OSPF Extended Prefix Range TLVs are advertised using AS-scope, the NSSA notion does not apply for them and does not restrict their flooding into or from NSSA areas (or stub areas for that matter). I am not sure if that answers your question. Thanks, Ketan -----Original Message----- From: Lsr <lsr-boun...@ietf.org> On Behalf Of Peter Psenak Sent: 18 August 2020 23:06 To: Veerendranatha Reddy V <veerendranatha.reddy.v=40ericsson....@dmarc.ietf.org>; lsr@ietf.org Subject: Re: [Lsr] Regarding OSPF Extended Prefix Range TLV usage for External/NSSA prefixes defined in RFC 8665 Veerendranath, On 18/08/2020 16:40, Veerendranatha Reddy V wrote: > Hi Authors, All, > > OSPF Extended Prefix Range TLV defined in RFC 8665 has IA flag to > distinguish between Intra and Inter Area scope prefixes. > > Whether any restrictions to not to use Prefix Range TLV for > external/NSSA prefixes ? I don't see how you can use OSPF Extended Prefix Range TLV for NSSA, the usage of OSPF Extended Prefix Range TLV has only been defined in the context of RFC 8665. thanks, Peter > > For External Prefixes, we can able to use Prefix Range TLV by using > LSA type (based on AS scope Opaque Type , so the TLV is for External > Prefixes) > > But If we need to use the Prefix Range TLV for NSSA prefixes (Type-7) > , which are in area scope, there is no flag/route-type field in this > TLV to distinguish between Intra or NSSA prefixes( as IA flag will not > be set anyway). > > Thanks & Regards, > > Veerendranath > _______________________________________________ Lsr mailing list Lsr@ietf.org https://www.ietf.org/mailman/listinfo/lsr _______________________________________________ Lsr mailing list Lsr@ietf.org https://www.ietf.org/mailman/listinfo/lsr
