The MPLS WG Archive

[Eric Gray <egray@sandburst.com>]

Jay,

    The phrase/term 'VPN-IPv4 Address Family' is certainly misleading, if it
is not also an outright misnomer.  There is nothing at all special about it
and
there is no (IANA) assigned family identifier associated with it.  It is, in
fact,
special only to BGP.  Indeed, it should have been identified as an address
'format', rather than an address 'family'.

    As you know, the distinction between this address format and that of IPv4
is that it includes an 8 byte route distinguisher (RD) and a 4 byte IPv4
prefix.
Other VPN proposals uses a (proposed standard) VPN identifier (consisting
of a 3 byte OUI and a 4 byte index - or 7 bytes total), instead of a route
distinguisher.  See RFC 2685 for more about VPN Identifiers.  Note that it
would be a trivial matter to embed a VPN ID in an RD.

--
Eric Gray

You wrote:

> LDP does not have a provision to carry information like VPN-IPv4 Address
> Family and can't be a substitute for BGP in implementing VPN. But the core
> routers in the provider domain, can facilitate PE to PE communication even
> without BGP being enabled.
>
> Jay
>
> At 04:09 AM 9/27/01 -0700, Ramyanshu Datta wrote:
> >hi,
> >
> >    the present  rfc on MPLS based VPNs uses BGP for
> >route  distribution. Can we  use LDP in place of BGP
> >for the same purpose.  and has  there been any work
> >done in this direction. if yes then please tell me the
> >links where i can find information about it
> >
> >Thanks in advance
> >Ramyanshu
> >
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