Supporting Load Sharing And Route Backup - Huawei Quidway S3500 Series Operation Manual

Operation Manual - Routing Protocol
Quidway S3500 Series Ethernet Switches
Routing protocol or route type
STATIC
RIP
OSPF ASE
OSPF NSSA
IBGP
EBGP
UNKNOWN
In the table, 0 indicates a direct route. 255 indicates any route from unreliable source.
Except for direct routing and BGP (IBGP and EBGP), the preferences of various
dynamic routing protocols can be manually configured to meet the user requirements.
In addition, the preferences for individual static routes can be different.

1.2.2 Supporting Load Sharing and Route Backup

I. Load sharing
Load sharing: Support multi-route mode, permitting to configure multiple routes that
reach the same destination and use the same precedence. The same destination can
be reached via multiple different paths, whose precedences are equal. When there is
no route that can reach the same destination with a higher precedence, the multiple
routes will be adopted by IP, which will forward the packets to the destination via these
paths so as to implement load sharing.
For the same destination, a specified routing protocol may find multiple different routes.
If the routing protocol has the highest precedence among all active routing protocols,
these multiple routes will be regarded as currently valid routes. Thus, load sharing of IP
traffic is ensured in terms of routing protocols.
By far, among S3500 Series Ethernet Switches, only S3552G, S3552P, S3528G and
S3528P support load-sharing. Each of them supports four routes to implement this
function.
II. Route backup
Route backup: Support route backup. When main route is in failure, the system will
automatically switch to a backup route to improve the network reliability.
In order to achieve route backup, the user can configure multiple routes to the same
destination according to actual situation. One of the routes has the highest precedence
and is called as main route. The other routes have descending precedences and are
called as backup routes. Normally, the router sends data via main route. When the line
The preference of the corresponding
60
100
150
150
256
256
255
Huawei Technologies Proprietary
1-5
Chapter 1 IP Routing Protocol Overview
route