Brocade FastIron Ethernet Switch Layer 3 Routing Configuration Guide - Manual (Page 287)

The default is type2.
Modify administrative distance
The device 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.
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 decision the
device makes by changing the default administrative distance for OSPF 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 device has multiple routes for the
same network from different protocols. The device prefers the route with the lower administrative
distance.
You can specify unique default administrative distances for the following route types:
• Intra-area routes
• Inter-area routes
• External routes
The default for all these OSPF route types is 110.
NOTE
This feature does not influence the choice of routes within OSPF. For example, an OSPF intra-area
route is always preferred over an OSPF inter-area route, even if the intra-area route’s distance is
greater than the inter-area route’s distance.
To change the default administrative distances for inter-area routes, intra-area routes, and external
routes, enter the following command.
device(config-ospf-router)# distance external 100
device(config-ospf-router)# distance inter-area 90
device(config-ospf-router)# distance intra-area 80
Syntax: [no] distance { external | inter-area | intra-area } distance
The distance external, inter-area , and intra-area parameters specify the route type for which you are
changing the default administrative distance.
The distance parameter specifies the new distance for the specified route type. Unless you change the
distance for one of the route types using commands such as those shown above, the default is 110.
To reset the administrative distance to its system default (110), enter a command such as the following.
device(config-ospf-router)# no distance external 100
Modify administrative distance
FastIron Ethernet Switch Layer 3 Routing Configuration Guide 287
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