4
Load sharing
A routing protocol can be configured with multiple equal-cost routes to the same destination. These routes
have the same preference and will all be used to accomplish load sharing if there is no route with a
higher preference available.
NOTE:
At present, routing protocols supporting load sharing include static routing/IPv6 static routing, RIP/RIPng,
OSPF/OSPFv3, BGP/IPv6 BGP, and IS-IS/IPv6 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 preference to be the main route and all the
rest backup routes.
Under normal circumstances, packets are forwarded through the main route. When the link fails, the
route with the highest preference among the backup routes is selected to forward packets. When the link
recovers, the route selection process is performed again and the main route is selected again to forward
packets.
Route recursion
The next hops of some BGP routes (except eBGP routes) and static routes may not be directly connected.
The outgoing interface to reach the next hop must be available. Route recursion is used to find the
outgoing interface based on the next hop information of the route. Link-state routing protocols, such as
OSPF and IS-IS, do not need route recursion because they obtain next hop information through route
calculation.
Route redistribution
Different routing protocols running on a network learn route information from each other through route
redistribution. Each routing protocol can redistribute routes from other protocols, direct routes, and static
routes. For more information, see relevant protocols in this configuration guide.
Displaying and maintaining a routing table
To do…
Use the command…
Remarks
Display information about the
routing table
display ip routing-table
[
vpn-instance
vpn-instance-name
] [
verbose
] [
|
{
begin
|
exclude
|
include
}
regular-expression
]
Available in any view
Display information about routes
permitted by an IPv4 basic ACL
display ip routing-table
[
vpn-instance
vpn-instance-name
]
acl
acl-number
[
verbose
]
[
|
{
begin
|
exclude
|
include
}
regular-expression
]
Available in any view
