Product guide

IP Routing Features
Configuring OSPF
Figure 5-41. Example of a Routing Table for the Network in Figure 5-40
Destination Subnet Router “A” Next Hop
10.1.0.0/16 Router “C”
10.2.0.0/16 Router “D”
10.3.0.0/16 Router “B”
10.32.0.0/16 Router “B”
10.42.0.0/16 Router “D”
Note that IP load-sharing does not affect routed traffic to different hosts on
the same subnet. That is, all traffic for different hosts on the same subnet will
go through the same next-hop router. For example, if subnet 10.32.0.0 includes
two servers at 10.32.0.11 and 10.32.0.22, then all traffic from router “A” to these
servers will go through router “B”.
Syntax: [no] ip load-sharing < 2 - 4 >
When OSPF is enabled and multiple, equal-cost, next-hop routes
are available for traffic destinations on different subnets, this
feature, by default, enables load-sharing among up to four next-
hop routes. The no form of the command disables this load-
sharing so that only one route in a group of multiple, equal-
cost, next-hop routes is used for traffic that could otherwise be
load-shared across multiple routes. For example, in figure5-40
on page 5-109, the next-hop routers “B”, “C”, and “D” are
available for equal-cost load-sharing of eligible traffic.
Disabling IP load-sharing means that router “A” selects only
one next-hop router for traffic that is actually eligible for load-
sharing through different next-hop routers. (Default: Enabled
with four equal-cost, next-hop routes allowed)
Note: In the default configuration, IP load-sharing is enabled
by default. However, it has no effect unless IP routing and OSPF
are enabled.
< 1 - 4 >
Specifies the maximum number of equal-cost next hop paths
the router allows. (Range: 2 - 4; Default: 4)
Displaying the Current IP Load-Sharing Configuration
Use the show running command to view the currently active IP load-sharing
configuration, and show config to view the IP load-sharing configuration in the
startup-config file. (While in its default configuration, IP load-sharing does not
appear in the command output.) If IP load sharing is configured with non-
5-110