[c-nsp] load sharing Vs load balancing

[Oliver Boehmer (oboehmer)]

david.ponsdesserre at uk.bnpparibas.com <> wrote on Monday, November 27,
2006 5:36 PM:

> Hello again people .
> 
> I need to come up with a load balancing solution for one of our
> customer . I have a question , may be it is a bit dumb but .... What
> is the actual difference between load balancing and load sharing ?

Well, both terms usually mean the same thing: Some technology to split
the load over multiple links.

> We will be using mainly Cisco Kit with Ebgp between our Pes
> and customers Ces  ( It is an Mpls connection )
> If you have any best practices on load balancing
> implementation other Ebgp please forward !!!

You might want to elaborate given the topology you have in mind, but in
MPLS networks, you ususally need some form of BGP multipath to split the
load. There are some standard scenarious:
 

                  PE2 -- CE2 \
CE1 --- PE1                   host
                  PE3 -- CE3 /

you need iBGP multipath to have the traffic from CE1 to use both PE2-CE2
and PE3-CE3 links.

If you have

     PE2 === CE2

you need eBGP multipath on the PE2 to use both links from PE2 to CE2
(assuming you use BGP as PE-CE)

There is another method specific to MPLS-VPN: eiBGP multipath:

                  CE4
                   |
                   |
                   |
                  PE2 -- CE2 \
CE1 --- PE1                   host
                  PE3 -- CE3 /


You need eiBGP multipath if you also want the traffic from CE4 to the
host behind CE2/CE3 to use both the direct eBGP link via CE2, as well as
the other link via PE3 to CE3.

Hope it helps..

	oli