H3C S7500E Series Ethernet Switches Operation Manual

Operation Manual – IP Routing Overview

H3C S7500E Series Ethernet Switches Chapter 1 IP Routing Overvie

1-5

Routing approach Priority

DIRECT

OSPF 10

IS-IS 15

STATIC 60

RIP 100

OSPF ASE 150

OSPF NSSA 150

IBGP 255

EBGP 255

UNKNOWN 256

 Note:

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.

1.2.4 Load Balancing and Route Backup

I. 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.

In current implementations, routing protocols supporting load balancing are static

routing, RIP, OSPF, BGP and IS-IS.

II. 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.