The MPLS WG Archive

[Curtis Villamizar <curtis@fictitious.org>]

In message <F69EB380D594D611BBEA00065B3F14B4A35257@MAIL>, Steve Yao writes:
> 
> 
> >I'm not sure how you reach that conclusion.  There is both addr and
> >neighbor in the IGP TE extensions for numbered interfaces.  The RRO
> >hops match the neighbor side.  That gives the exact IGP LSAs or LSPDU
> >TLVs and gives the near side (the one likely to arrive first).
> >
> 
> >When a link goes down, one LSA or LSPDU fragment is originated by two
> >LSR, one on each side of the link.  When either LSA/LSPDU arrives, the
> >TE-LSDB unidirectional adjacency (or link) in both directions is
> >considered down.  The two unidirectional data structures each have a
> >set of MPLS LSP data structures linked to them (actually other small
> >structures that point to the LSP, but that's some of the data
> >structures 101 material).
> >
> >If you mean that the LSA/LSPDU for the type-2/pseudonode of a
> >broadcast interface is not explicitly present, then quite frankly,
> >knowing the node of the previous hop and the next interface this is
> >not an incredibly hard problem to solve either.
> >
> >If that's not what you meant, please let me know.
> >
> >Curtis
> >
> 
> Yes. You are right. I missed the link ID and pseudonode.
> Then there is the case where RRO may be too large. What cases were you
> thinking of?
> 
> Steve


Steve,

In two messages prior you stated:

> The RRO received at the HE only contains the IP addresses that map to half
> of the LSAs or LSPs that the LSP traversed. 

You mentioned that only half the LSA/LSPDU were in the RRO, so the
question "What cases were you thinking of?" that you just asked should
be directed to you.

Since you brought up the issue "where RRO may be too large" why don't
you do the math and tell us 1) how big the RRO would have to be to be
too large and 2) how likely you think that is of occurring.  RSVPd
objects can be 64KB each.  The IPv4 address subobject is 8 bytes long,
including type and length.  Add a label subobject (8 bytes) and fit it
into a reasonable MTU and you're still at hundreds of hops.  I get
200+ into a 4KB MTU and most networks seem to be going for 8K MTU so I
get "not very likely" for question 2).

Curtis