The MPLS WG Archive

[David Charlap <david.charlap@marconi.com>]

Gray, Eric wrote:
> 
> 	This opens the way to a lazy man's LSR - one
> which performs no ingress or egress functions but
> simply forwards packets as it receives them.  I.e.
> labeled packets are forwarded labeled, unlabeled
> packets are forwarded unlabeled.  There are many
> issues with such an implementation, since it can't
> provide or maintain labels for which it does not
> have downstream bindings.  I believe such an LSR
> would be exceptionally fragile and unlikely to be
> of much use as a result - but I mention it mostly
> for completeness.  

Such a device could be stable if it uses RSVP or CR-LDP (or even LDP if 
downstream-on-demand/conservative-retention mode is used).  If all LSPs 
are created using strict EROs, you don't even need routing functionality.

But you're right that such a product would not be useful to most people. 
  Once you've paid enough money to get good forwarding hardware, you're 
going to want routing and LER capabilities.

-- David