Load balancing across serial links

new_networker · ‎11-17-2008

On a single router that has multiple serial links, how can load balancing be achieved across them.

- per-packet sharing is not accepted by the team due to out of order issue

- there is only one destination (per-destination sharing will cause an over utilization of one of the links) so how can round robin load balancing be done. That is every new connection is diverted to a different serial link.

Giuseppe Larosa · ‎11-17-2008

Hello New,

if at the other end of the multiple serial interfaces there is another single device you can think to use multilink PPP.

Multilink PPP will use its own round robin logic to provide load balancing over the links without using the CEF load balancing

see

http://www.cisco.com/en/US/docs/ios/dial/configuration/guide/dia_media-ind_multi_ppp_ps6350_TSD_Products_Configuration_Guide_Chapter.html#wp1022210

Hope to help

Giuseppe

Joseph W. Doherty · ‎11-17-2008

Besides Giuseppe's suggestion of using MLPPP, CEF, even for non-per-packet load balancing, is described (see http://www.cisco.com/en/US/products/hw/modules/ps2033/prod_technical_reference09186a00800afeb7.html) as hashing both source and destination IP addresses. So unless your traffic is just between a pair of hosts, there should be some load balancing.