Brocade Communications Systems Layer 3 Routing Configuration ICX 6650 - Manual (Page 221)

Brocade ICX 6650 Layer 3 Routing Configuration Guide 203
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Configuring OSPF
FIGURE 24 Example OSPF network with four equal-cost paths
In the example in Figure 24 , the Brocade switch has four paths to R1:
• Brocade Switch->R3
• Brocade Switch->R4
• Brocade Switch->R5
• Brocade Switch->R6
Normally, the Brocade switch will choose the path to the R1 with the lower metric. For example, if
R3 metric is 1400 and R4 metric is 600, the Brocade switch will always choose R4.
However, suppose the metric is the same for all four routers in this example. If the costs are the
same, the switch now has four equal-cost paths to R1. To allow the switch to load share among the
equal cost routes, enable IP load sharing. The software supports four equal-cost OSPF paths by
default when you enable load sharing. You can specify from 2 to 6 paths.
NOTE
The Brocade switch is not source routing in these examples. The switch is concerned only with the
paths to the next-hop routers, not the entire paths to the destination hosts.
OSPF load sharing is enabled by default when IP load sharing is enabled. To configure IP load
sharing parameters, refer to
“Configuring IP load sharing” on page 55.
OSPF Area 0
H1
H2
H3
H4
R1
R3
R4
R5
R6
Brocade Switch