[j-nsp] VPLS Multihoming on Junos - FEC confusion

[Darren O'Connor]

Hi list.

I'm going over the VPLS multihoming options on Juniper's web site. I'm not concerned with LAG and MC-LAG for the moment.

As far as I'm aware, FEC128 is when you are using manual discovery of pseudowires (LDP) - FEC129 is when you are using BGP auto-discovery.

Juniper techpub for FEC129 multihoming I don't have a problem with as it shows how to multihome with BGP: https://www.juniper.net/techpubs/en_US/junos/topics/topic-map/vpls-bgp-multihoming.html

The FEC128 multihome techpub says that you cannot enable LDP signalling, you have to use BGP signalling: http://www.juniper.net/techpubs/en_US/junos/topics/usage-guidelines/vpns-configuring-vpls-multihoming.html


I know that you can use LDP for manual discovery and LDP will then signal VC labels. You can also use BGP for auto-discovery and LDP for VC label signalling. You can also use BGP for both.

What I don't get is how you could use FEC128 with BGP signalling. Junos doesn't give you the option to only signal through BGP but manual discovery through LDP.

So my question is, when exactly would the FEC128 config be used over the FEC129 config? If you are using BGP for signalling are you not using BGP for discovery at the same time?

Or maybe I'm just misunderstanding something.


Thanks
Darren
http://www.mellowd.co.uk/ccie