The MPLS WG Archive

[Nabil Seddigh <nseddigh@tropicnetworks.com>]

Yakov,

I agree that the RSVP-TE-09 draft section 4.3.3.2 doesn't explicitly
state if the numbered ip addr is outgoing or incoming. However,
I think it's generally accepted that the ERO ip sub-object 
always specifies the next-hop incoming interface ip address?

I don't believe this is the case for unnumbered. Some folks seem
to want outgoing i/f while others want incoming i/f while yet
others propose both incoming and outgoing i/f be specified 
(Bora Akyol's draft).

I think something precise needs to be written in the unnumbered 
draft. For that matter, I think section 4.3.3.2 of the rsvp-te-09
can also benefit from added precision.

Best,
Nabil



> Nabil,
> 
> > The next question is just begging to be asked. If both B2,C4,D6
> > and A1,B3,C5 are valid EROs, does this not pose interoperability
> > problems?
> 
> No more no less than if the interface would be numbered.
> 
> > Maybe it's useful to add a field in the unnum ero subobject
> > that specifies whether the i/f is outgoing or incoming relative
> > to the router id. The draft could also mandate that all ero
> > subobjects in a PATH msg must be of the same type - i.e.
> > have i/f that are incoming or outgoing.
> 
> there is no such restriction when interfaces are numbered.
> Therefore, there is no need to place such restriction when
> interfaces are unnumbered.
> 
> Yakov.
> 
> >
> > Best,
> > Nabil
> >
> >
> >
> > > > >From what you write below, the ERO will be B2,C4,D6.
> > > > Is this correct?
> >
> > > yes, this is certainly a valid option.
> > >
> > > > Another question: is your proposal precluding an ERO of
> > > > A1,B3,C5?
> > >
> > > no, it doesn't preclude this.
> > >
> > > Yakov.
> > >
> > > > >>>> in the draft? E.g if we have nodes A,B,C,D with unnumbered i/f
> > > > >>>> 1-6 (I have made them distict for ease of illustration):
> > > > >>>>
> > > > >>>>       1       2   3          4   5      6
> > > > >>>>     A --------- B ------------ C -------- D
> > > > >>>
> > > > >>> Certainly not, as I am proposing that "The Interface ID is
> > > > >>> the interface identifier assigned to the interface by the LSR
> > > > >>> specified by the router ID.