Re: : MPLS load sharing

>   I know that OSPF can do load sharing to maximum of 6 paths. My question - is load sharing possible based on
MPLS label?

I sense some misunderstanding here. First, there is nothing specific
in OSPF which says load sharing to a maximum of 6 paths. Second, it is
the *forwarding* part of the router which does the load sharing - OSPF
simply computes routes based on received information.

Different router platforms have different limitations on the number
of paths that can be used for load sharing. The load sharing is often
done by computing a hash of L3 and L4 information (and for switches,
L2 information like MAC address) and using this to ensure that all the
packets in one *flow* (identified by the same L3/L4 information) is
sent along the same path, to prevent reordering of packets.

Load sharing based on MPLS labels simply means that the router can use
MPLS labels as path of the hash. This is fairly common - for instance
the following for Juniper M/T series routers:

http://www.juniper.net/techpubs/software/junos/junos81/swconfig81-policy/html/policy-actions-config12.html#1020348

Steinar Haug, Nethelp consulting, sthaug <at> nethelp.no