The MPLS-OPS Archive

["john smith" <johnsmith0302@hotmail.com>]

by the way,
if BGP is generating the inner label...
why cant we use it as the "last label" to the PE rather than have a label in
label or a label in GRE?

isnt that possible too?

coz we already know what the inner label is at both ends now....

there was a talk about inter-provider RSVP signalling..what about that?

----- Original Message -----
From: john smith <johnsmith0302@hotmail.com>
To: <raszuk@cisco.com>
Cc: MPLS-ops Mailing List <mpls-ops@mplsrc.com>
Sent: Monday, February 24, 2003 1:19 PM
Subject: Re: Fwd: Re: RE: [MPLS-OPS]: Route Distinguisher Questions


> hi Robert,
>
> seems we are on the same side in somethings... :-)
> inline.....
>
> ----- Original Message -----
> From: Robert Raszuk <raszuk@cisco.com>
> To: john smith <johnsmith0302@hotmail.com>
> Cc: MPLS-ops Mailing List <mpls-ops@mplsrc.com>
> Sent: Monday, February 24, 2003 10:14 AM
> Subject: Re: Fwd: Re: RE: [MPLS-OPS]: Route Distinguisher Questions
>
>
> > John,
> >
> > > How many bits does the RD field have?? :-o are they enuf to put an AS
#
> in
> > > it? and make it globally unique?
> >
> > 8 bytes = 64 bits ... :).
>
> :o) so why did we ever make RT?
>
> >
> >    The RDs are structured so that every service provider can administer
> >    its own "numbering space" (i.e., can make its own assignments of
> >    RDs), without conflicting with the RD assignments made by any other
> >    service provider.  An RD consists of a two-byte type field, an
> >    administrator field, and an assigned number field.  The value of the
> >    type field determines the lengths of the other two fields, as well as
> >    the semantics of the administrator field.  The administrator field
> >    identifies an assigned number authority, and the assigned number
> >    field contains a number which has been assigned, by the identified
> >    authority, for a particular purpose.  For example, one could have an
> >    RD whose administrator field contains an Autonomous System number
> >
> > Rosen & Rekhter              Informational                      [Page 9]
> > RFC 2547                     BGP/MPLS VPNs                    March 1999
> >
> >    (ASN), and whose (4-byte) number field contains a number assigned by
> >    the SP to whom IANA has assigned that ASN.  RDs are given this
> >    structure in order to ensure that an SP which provides VPN backbone
> >    service can always create a unique RD when it needs to do so.
> >    However, the structuring provides no semantics. When BGP compares two
> >    such address prefixes, it ignores the structure entirely.
>
> .............so u still need "RT" ??? (well yeah it has more bits than RD
> ;-) )
>
> .......was it made for CoC and Multiple ASes, or was it made for something
> else????
>
> and now that we maybe able to "filter on RD" since they will be globally
> unique..why not put RT to a better use...any ideas how?
>
> ...............i see it having a greater significance... in terms of
> community scenarios.....
>
> >
> > > so we still have a label stack, the LDP gives u the LSP to the end PE
> and
> > > the inner label to identify the VRF is passed by BGP?
> > > is this correct?
> >
> > If you use LDP yes - if you use IP for getting to your remote PE - No.
> >
> > > now, how do we generate the inner label?
> >
> > Inner label (VPN label) is generated by BGP in any case.
>
> ..........agreed..draft kompella ppvpn i presume?
>
>
> >
> > > and in case we go across multiple service providers, how do we handle
it
> in
> > > such scenarios?
> > >
> > > as now we would have a "outer label", an "inner label" and put the
> remote
> > > AS' router loopback into your IGP? how exciting!
> >
> > No need. If you use IP for transport of 2547 there is no outer label and
> > you don't need to put your remote AS's loopacks into any IGP. Most
> > implementations I know can handle mutli level recursion just fine.
>
> ........ahha i presume GRE or IP-IP kind of encap?
>
> .......and how would you use those "nasty inner layer protocol bits" inthe
> GRE header.,.why dont you just do away with them and put the MPLS Label
> there?
>
> .......and then how will you do RSVP -TE (by the way does cisco support
> TED)?
>
> .......and i mean is TED more that a "show" command ?
>
>
>
>

-------
The MPLS-OPS Mailing List
Subscribe/Unsubscribe:  http://www.mplsrc.com/mplsops.shtml
Archive: http://www.mplsrc.com/mpls-ops_archive.shtml