The MPLS WG Archive

[Marc Binderberger <marc@sniff.de>]

Hi Roger,

>  If i have "send label" configured for a BGP peer, do the peers need 
> to be on directly
> connected interfaces?

No other MPLS hop(s) in between, right. That's at least the "usual" 
scenario.

>  If it is not, how would the MPLS switches in between know
> about the labels?

They don't know unless you configure them, e.g. by means of static 
labels.


> And if it is on directly connected interfaces, does it allocate a 
> label from  the interface label space of that interface?

The routers I have seen use a global label pool, not per-interface.
Well ... what (should) exist is an information that relates the label 
to the interface, maybe something similar to Carrier's Carrier where 
the label is related to the VRF the interface is part of. If this 
information doesn't exist you cannot prevent label spoofing


>   I guess, for carrier's Carrier case, the CEs need to be on directly 
> connected interfaces with the PE.

Same as above, when there is a label-switch device in between how does 
it know about the labels in/out?
Again for routers (the one I know) it's a global pool together with 
information about the VRF the labels have been advertised in.


Regards, Marc
--
Marc Binderberger    <marc@sniff.de>    Powered by *BSD ;-)