Traffic Sharing And Route Backup - Huawei Quidway S3900 Series Operation Manual

Operation Manual – Routing Protocol
Quidway S3900 Series Ethernet Switches-Release 1510
route. Routing protocols and their default route preferences (the smaller the value, the
higher the preference is) are shown in Table 1-1.
In the table, "0" is used for directly connected routes, and "255" is used for routes from
untrusted source.
Table 1-1 Routing protocols and corresponding route preferences
Routing protocol or type
DIRECT
OSPF
STATIC
RIP
OSPF ASE
OSPF NSSA
UNKNOWN
Except for direct routing, you can manually configure the preferences of various
dynamic routing protocols as required. In addition, you can configure different
preferences for different static routes.

1.2.2 Traffic Sharing and Route Backup

I. Traffic sharing
The S3900 series support multi-route mode, allowing the configuration of multiple
routes that reach the same destination and have the same preference. The same
destination can be reached via multiple different routes, whose preferences are equal.
When there is no route with a higher preference to the same destination, the multiple
routes will be adopted. Then, the packets destined for the same destination will be
forwarded through these routes in turn to implement traffic sharing.
II. Route backup
The S3900 series support route backup. When the main route fails, the system
automatically switches to a backup route to improve network reliability.
To achieve route backup, you can configure multiple routes to the same destination
according to actual situation. One of the routes has the highest preference and is
called primary route. The other routes have descending preferences and are called
backup routes. Normally, the router sends data through the main route. When line
failure occurs on the main route, the main route will hide itself and the router will
choose the one whose preference is the highest among the remaining backup routes
as the path to send data. In this way, the switchover from the main route to a backup
Preference of the corresponding route
0
10
60
100
150
150
255
Huawei Technologies Proprietary
1-5
Chapter 1 IP Routing Protocol Overview