Reference Guide

CONFIG-ROUTEROSPF- id mode
area area-id virtual-link router-id [hello-interval seconds | retransmit-interval seconds
| transmit-delay seconds | dead-interval seconds | authentication-key key | message-
digest-key keyid md5 key]
○ area ID: assigned earlier (the range is from 0 to 65535 or A.B.C.D).
○ router ID: IP address associated with the virtual link neighbor.
○ hello interval seconds: the range is from 1 to 8192 (the default is 10).
○ retransmit interval seconds: the range is from 1 to 3600 (the default is 5).
○ transmit delay seconds: the range is from 1 to 3600 (the default is 1).
○ dead interval seconds: the range is from 1 to 8192 (the default is 40).
○ authentication key: eight characters.
○ message digest key keyid: the range is from 1 to 255.
○ md5 key: 16 characters.
If you do not enter other parameters, the defaults are used.
Only the area ID and router ID require configuration to create a virtual link.
Use EITHER the Authentication Key or the Message Digest (MD5) key.
Use the show ip ospf process-id virtual-links command to view the virtual link.
Dell#show ip ospf 1 virtual-links
Virtual Link to router 192.168.253.5 is up
Run as demand circuit
Transit area 0.0.0.1, via interface TengigabitEthernet 13/16, Cost of using 2
Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:02
Dell#
Creating Filter Routes
To filter routes, use prefix lists. OSPF applies prefix lists to incoming or outgoing routes.
Incoming routes must meet the conditions of the prefix lists. If they do not, OSPF does not add the route to the routing table.
Configure the prefix list in CONFIGURATION PREFIX LIST mode prior to assigning it to the OSPF process.
● Create a prefix list and assign it a unique name.
CONFIGURATION mode
ip prefix-list prefix-name
You are in PREFIX LIST mode.
● Create a prefix list with a sequence number and a deny or permit action.
CONFIG- PREFIX LIST mode
seq sequence-number {deny |permit} ip-prefix [ge min-prefix-length] [le max-prefix-
length]
The optional parameters are:
○ ge min-prefix-length: is the minimum prefix length to match (from 0 to 32).
○ le max-prefix-length: is the maximum prefix length to match (from 0 to 32).
For configuration information about prefix lists, refer to Access Control Lists (ACLs).
Applying Prefix Lists
To apply prefix lists to incoming or outgoing OSPF routes, use the following commands.
● Apply a configured prefix list to incoming OSPF routes.
CONFIG-ROUTEROSPF-id mode
538
Open Shortest Path First (OSPFv2 and OSPFv3)