Dual vsat link load balancing

coletemple · ‎05-08-2009

Hi,

We are trying to get another vsat(from another provider) to fulfill the need of our numerous customers and since the second vsat will come with a second different subnet of IP addresses, we want to find a way to implement on our edge router a mechanism of load balancing traffic with these necessities:

1-send any other traffic to vsat2(link2) when vsat1(link1) is congested (we'll have to define a threshold of congestion and customers will be redirected using subnet2)

2-priority will be given to vsat1 (with subnet1)when traffic has not reached the threshold but traffic will be shared accross the two links.

I was looking toward the direction of some bandwidth management equipment (packeteer or similar) to find a solution but I've been told that i could use BGP also for this.

Any idea?

Giuseppe Larosa · ‎05-08-2009

Hello Paul,

if both vsat links are terminated on the same router you can declare vsat2 backup of vsat1 and you can specify the conditions of load that triggers vsat2 usage.

Router(config-if)# backup load {enable-threshold | never} {disable-load | never}

see

http://www.cisco.com/en/US/docs/ios/dial/configuration/guide/dia_backup_serial_ps6350_TSD_Products_Configuration_Guide_Chapter.html#wp1000951

between the two load thresholds both links are used.

You may need to combine this with other features like reliable static routing for redundancy.

http://www.cisco.com/en/US/docs/ios/12_3/12_3x/12_3xe/feature/guide/dbackupx.html

Another possible option is to take advantage of EIGRP capabilities to load balance over an-equal cost paths using variance.

In this case however, there is no load threshold trigger and vsat2 can be made less used then vsat1.

Unfortunately an interface that is backup of another one cannot run a routing protocol (it is stopped by backup feature) so the two solutions cannot be combined.

Hope to help

Giuseppe

Joseph W. Doherty · ‎05-08-2009

OER/PfR technology has the capability to dynamically load balance. Many restrictions on what's required to use it, though.