H3C Technologies H3C S7500E Series Switches - Manual (Page 22)

1-5
Routing approach Priority
IBGP 255
EBGP 255
UNKNOWN 256
z The smaller the priority value, the higher the priority.
z The priority for a direct route is always 0, which you cannot change. Any other type of routes can
have their priorities manually configured.
z Each static route can be configured with a different priority.
z IPv4 and IPv6 routes have their own respective routing tables.
Load Balancing and Route Backup
Load Balancing
In multi-route mode, a routing protocol can be configured with multiple equal-cost routes to the same
destination. These routes have the same priority and will all be used to accomplish load balancing if
there is no route with a higher priority available. A given routing protocol may find several routes with
the same metric to the same destination, and if this protocol has the highest priority among all the
active protocols, these routes will be considered valid routes for load balancing.
z The number of routes for load balancing is 8.
z In current implementations, routing protocols supporting load balancing are static routing, RIP,
OSPF, BGP, and IS-IS.
Route backup
Route backup can help improve network reliability. With route backup, you can configure multiple
routes to the same destination, expecting the one with the highest priority to be the main route and all
the rest backup routes.
Under normal circumstances, packets are forwarded through the main route. When the main route
goes down, the route with the highest priority among the backup routes is selected to forward packets.
When the main route recovers, the route selection process is performed again and the main route is
selected again to forward packets.