From: Jelle Borsje (borsjej@yahoo.dk)
Date: Tue Apr 12 2005 - 10:55:52 GMT-3
Hi,
When configuring this, a virtual interface is created
on the router, called a bundle. The physical
interfaces that make up for the bundle, are called
bundle-links. The latter are invisible to the
frame-relay data-link layer, and the frame-relay
functionality is therefore not configured on the
bundle-links (or physical interface) but on the bundle
(the virtual interface).
It appears that over the bundle-links, Link Integrity
Protocol Control Messages are exchanged. LMI (and with
that the advertisement of DLCIs) is configured on the
virtual interface. LMI is up, and the connection
active, as long as a single bundle-link is up and
running.
Since LMI is not running on the bundle-links (physical
interfaces), the DLCIs are not advertised on the
physical links... but only on the virtual interface.
As far as your routing and connectivity is concerned,
you only have to worry about the virtual interface.
The FRF.16 standard will make sure that the packets
are divided over the multiple bundle-links (physical
interfaces) and reconstructed in the correct order on
the other side.
Hope this helps.
Greetz
Jelle
--- Sean C <Upp_and_Upp@hotmail.com> wrote:
> Hello,
>
> When implementing Multilink Frame Relay (FRF.16) -
> I'm trying to understand
> how the carrier advertises PVCs. My question is
> this: does the carrier
> advertise all PVCs on each T1?
>
> IOW - if an original implementation of FR had 2 T1s
> with the 1st T1 utilizing
> PVCs # 1, 2 & 3 and the 2nd T1 utilizing PVCs # 4, 5
> & 6. If wishing to
> utilize Multilink FR, does the carrier now need to
> advertise all PVCs on both
> T1s? IOW - will the 1st T1 now carry PVCs # 1, 2,
> 3, 4, 5 & 6 and the 2nd T1
> will carry the same PVCs #1, 2, 3, 4, 5, & 6? It's
> the only way I can see
> this happening because I can't figure out if the 2nd
> T1 fails, how the 1st T1
> will be able to support PVCs 4, 5 & 6.
>
> I appreciate any answer supplied. I hope my
> question is stated simply enough.
> I had searched on CCO:
>
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122t
> /122t8/ft_mfr.htm
> and Googled some but have not found the appropriate
> answer.
>
> Thanks in advance,
> Sean
>
>
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