Dell PowerConnect B-FCXs, Руководство по настройке

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PowerConnect B-Series FCX Configuration Guide 959
53-1002266-01
Configuring OSPF
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You can set the delay and hold time to lower values to cause the Layer 3 Switch to change to
alternate paths more quickly in the event of a route failure. Note that lower values require more
CPU processing time.
You can change one or both of the timers. To do so, enter commands such as the following.
PowerConnect(config-ospf-router)#timers spf 10 20
The command in this example changes the SPF delay to 10 seconds and changes the SPF hold
time to 20 seconds.
Syntax: timers spf <delay> <hold-time>
The <delay> parameter specifies the SPF delay.
The <hold-time> parameter specifies the SPF hold time.
To set the timers back to their default values, enter a command such as the following.
PowerConnect(config-ospf-router)#no timers spf 10 20
Modifying the redistribution metric type
The redistribution metric type is used by default for all routes imported into OSPF unless you
specify different metrics for individual routes using redistribution filters. Type 2 specifies a big
metric (three bytes). Type 1 specifies a small metric (two bytes). The default value is type 2.
To modify the default value to type 1, enter the following command.
PowerConnect(config-ospf-router)#metric-type type1
Syntax: metric-type type1 | type2
Modifying the administrative distance
Layer 3 Switches can learn about networks from various protocols, including Border Gateway
Protocol version 4 (BGP4), RIP, and OSPF. Consequently, the routes to a network may differ
depending on the protocol from which the routes were learned. The default administrative
distance for OSPF routes is 110. Refer to
“Changing administrative distances” on page 1014 for a
list of the default distances for all route sources.
The router selects one route over another based on the source of the route information. To do so,
the router can use the administrative distances assigned to the sources. You can bias the Layer 3
Switch decision by changing the default administrative distance for RIP routes.
Configuring administrative distance based on route type
You can configure a unique administrative distance for each type of OSPF route. For example, you
can use this feature to prefer a static route over an OSPF inter-area route but you also want to
prefer OSPF intra-area routes to static routes.
The distance you specify influences the choice of routes when the Layer 3 Switch has multiple
routes for the same network from different protocols. The Layer 3 Switch prefers the route with the
lower administrative distance.
You can specify unique default administrative distances for the following route types:
•
Intra-area routes