Peter, I suggest changing the paragraph to read as below to make this clearer.
===== The SR-Algorithm Sub-TLV is optional. It MAY only be advertised once in the Router Information Opaque LSA. If the SID/Label Range TLV, as defined in Section 3.2, is advertised, then the SR-Algorithm TLV MUST also be advertised. If a router C advertises a Prefix-SID sub-TLV for algorithm X but does not advertise the SR-Algorithm Sub-TLV with algorithm X, then a router receiving that advertisement MUST ignore the Prefix-SID advertisement from router C. If router B does not advertise the SR-Algorithm TLV for algorithm X, then other routers should not forward traffic destined for a prefix-SID for algorithm X advertised by some router D using a path that would require router B to forward traffic using algorithm X. ===== Thanks, Chris -----Original Message----- From: Peter Psenak [mailto:[email protected]] Sent: Monday, August 15, 2016 6:40 AM To: Chris Bowers <[email protected]>; OSPF List <[email protected]> Subject: Re: [OSPF] OSPFv2 SR draft Hi Chris, sorry for the delay, I was on PTO during last two weeks. Please see inline: On 03/08/16 16:45 , Chris Bowers wrote: > Peter, > > Taking a looking at the whole paragraph into this sentence was added, > I am not sure how to interpret it. > > The SR-Algorithm Sub-TLV is optional. It MAY only be advertised once > in the Router Information Opaque LSA. If the SID/Label Range TLV, as > defined in Section 3.2, is advertised, then the SR-Algorithm TLV MUST > also be advertised. If the SR-Algorithm TLV is not advertised by the > node, such node is considered as not being segment routing capable. > > Is this sentence intended to imply that if a router does not advertise > the SR-Algorithm TLV including algorithm X, then any prefix-SIDs for > algorithm X advertised by that router will be ignored by other routers? in OSPF we do not have the SR capability TLV. We use SR-Algorithm TLV for that purpose. So if a router does not advertise the SR-Algorithm TLV for algorithm X, other routers should not send any SR traffic using SIDs that were advertised for algorithm X. If the router does not advertise any SR Algorithm TLV, then the node is not SR capable and no SR traffic should be forwarded to such a node. thanks, Peter > > If this is the intention, then it would be better to state is more explicitly. > > If not, then the intended meaning should be clarified. > > Thanks, > Chris > > > -----Original Message----- > From: OSPF [mailto:[email protected]] On Behalf Of Peter Psenak > Sent: Friday, July 22, 2016 3:30 AM > To: OSPF List <[email protected]> > Subject: [OSPF] OSPFv2 SR draft > > Hi All, > > following text has been added in the latest revision of the OSPFv2 SR > draft, section 3.1. > > "If the SR-Algorithm TLV is not advertised by node, such node is > considered as not being segment routing capable." > > Please let us know if there are any concerns regarding this addition. > > thanks, > Peter > > _______________________________________________ > OSPF mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/ospf > . > _______________________________________________ OSPF mailing list [email protected] https://www.ietf.org/mailman/listinfo/ospf
