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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter 22 Configuring IP Unicast Routing
Configuring OSPF
Use the no form of these commands to remove the configured parameter value or return to the
default value.
This is an example of output from the show ip ospf interface privileged EXEC command:
Switch# show ip ospf interface
Vlan1 is up, line protocol is up
Internet Address 172.20.135.202/14, Area 1
Process ID 1, Router ID 172.20.135.202, Network Type BROADCAST, Cost: 1
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 172.20.135.202, Interface address 172.20.135.202
No backup designated router on this network
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:02
Index 1/1, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 0, maximum is 0
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 0, Adjacent neighbor count is 0
Suppress hello for 0 neighbor(s)
OSPF Area Parameters
You can optionally configure several OSPF area parameters. These parameters include authentication
for password-based protection against unauthorized access to an area, stub areas, and
not-so-stubby-areas (NSSAs). Stub areas are areas into which information on external routes is not sent.
Instead, the area border router (ABR) generates a default external route into the stub area for destinations
outside the autonomous system (AS). An NSSA does not flood all LSAs from the core into the area, but
can import AS external routes within the area by redistribution.
Route summarization is the consolidation of advertised addresses into a single summary route to be
advertised by other areas. If network numbers are contiguous, you can use the area range router
configuration command to configure the ABR to advertise a summary route that covers all networks in
the range.
Step 9
ip ospf authentication-key key
(Optional) Assign a password to be used by neighboring OSPF
routers. The password can be any string of keyboard-entered
characters up to 8 bytes in length. All neighboring routers on the
same network must have the same password to exchange OSPF
information.
Step 10
ip ospf message digest-key keyid md5 key
(Optional) Enable MDS authentication.
•
keyid—An identifier from 1 to 255.
•
key—An alphanumeric password of up to 16 bytes.
Step 11
ip ospf database-filter all out
(Optional) Block flooding of OSPF LSA packets to the interface. By
default, OSPF floods new LSAs over all interfaces in the same area,
except the interface on which the LSA arrives.
Step 12
end
Return to privileged EXEC mode.
Step 13
show ip ospf interface [interface-name]
Display OSPF-related interface information.
Step 14
copy running-config startup-config
(Optional) Save your entries in the configuration file.
Command
Purpose
