[c-nsp] Load balancing/sharing

[Pete Templin]

c-nsp at netophilia.net wrote:
> Hello,
> I currently have a single GigabitEthernet link between 2 Cisco 12008
> routers connecting our sites (about 130 miles between us). One of the
> routers is speaking bgp with our upstreams, and we also have an internal
> bgp session between the routers. As we have approached full utilization on
> this Gigabit link, we have now ordered a second Gigabit link between the
> sites. This Gigabit link will initially be only 200 Mb/s. Basically, the
> new Gigabit link was purchased to handle the overflow from the initial
> Gigabit link. Question is, is there a way for me to configure load sharing
> across these unequal internal links, should I be looking to route specific
> subnets across the 2 links to manually split the load, or is there some
> other way to accomplish this? Thanks for any input.

MPLS Traffic Engineering:

Make sure you have maximum-paths 8 in your IGP config.
Enable MPLS on all four interfaces.
Allow 800Mbps (adjust as desired) to be reserved on each interface.
Write an explicit path over the first GE in each direction.
Build 6 or 8 TE tunnel interfaces pointing to the opposite router.
Use the explicit path first (lower "priority"), dynamic path second.
Autoroute over the tunnels.
Enable auto-bandwidth on the tunnels.

Traffic will stick to the first interface until the interface has a 
regular traffic of 800Mbps, at which point roughly 1/6th or 1/8th of 
your traffic will flip to the second interface.  More increments will 
flip over to the second interface.

pt