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Cisco ME 3400 EthernetAccess Switch SoftwareConfiguration Guide
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Chapter32 Configuring IP Unicast Routing Configuring Protocol-Independent Features
Use the no distribute-list in router configuration command to change or cancel a filter. To cancel
suppression of network advertisements in updates, use the no distribute-list out rout er c on figuration
command.
Filtering Sources of Routing Information
Because some routing information might be more accurate than others, you can use filtering to prioritiz e
information coming from different sources. An administrative distance is a rating of the trustworthiness
of a routing information source, such as a router or group o f rout ers. I n a l arge ne twork, so me r outing
protocols can be more reliable than others. By specifying administrati v e dist ance v alu es, you enable the
router to intelligently discriminate between sources of routing in formation. The router always picks the
route whose routing protocol has the lowest administrative distance. Table 32-14 on page 32-71 shows
the default administrative distances for various routing information sources.
Because each network has its own requirements, there are no general guidelines for assigning
administrative distances.
Beginning in privileged EXEC mode, follow these steps to filter sources of routing information:
To remove a distance definition, use the no distance router configuration command.
Step5 end Return to privileged EXEC mode.
Step6 copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 router {bgp | rip | ospf | eigrp} Enter router configuration mode.
Step3 distance weight {ip-address {ip-address mask}}
[ip access list]Define an administrative distance.
weight—The administrative distance as an integer from
10 to 255. Used alone, weight specifies a default
administrative distance that is used when no other
specification exists for a routing information source.
Routes with a distance of 255 are not installed in the
routing table.
(Optional) ip access list—An IP standard or extended
access list to be applied to incoming routing updates.
Step4 end Return to privileged EXEC mode.
Step5 show ip protocols Display the default administrative distance for a
specified routing process.
Step6 copy running-config startup-config (Optional) Save your entries in the configuration file.