Frequently Asked Questions (FAQ)

1:	Can I load-balance/load-share across redundant WAN access links?
A1:	Yes. It is the network administrator's preference to use both links in a simultaneous fashion or to leave the backup WAN link idle and in standby for failure of the primary WAN link. This decision often is based on the cost of the WAN link. For example, a dedicated WAN link might prove to be more cost-efficient by being used in a load-balance/load-share environment as opposed to letting the link sit there idle and unused.
2:	Why is BGP the most often used routing protocol for redundant IP VPN WAN links?
A2:	BGP enables a customer site, or group of sites, to be treated as a single domain (autonomous system) and establish a peering relationship with the network service provider IP network. For ATM and Frame Relay WANs, any routing protocol can be used by the network administrator because the network service provider does not see customer routing protocols used across the WAN. The routing protocol detects and reacts to a link failure by the routing protocol provisions for metric weighting, enabling the network administrator to give one route preference over another route, either manually or through the use of the default metrics.