area virtual-link
(OSPFv2)
Creates or modifies virtual links for an area.
Syntax
area
{
ip-addr
|
decimal
}
virtual-link
E.F.G.H
[
authentication-key
password
]
[
dead-interval
time
]
[
hello-interval
time
]
[
md5-authentication
{
key-activation-wait-time
time
|
key-id
num
key
}
]
[
retransmit-interval
time
]
[
transmit-delay
time
]
Command Default
No virtual links are created.
Parameters
-
ip-addr
- Area address in IP address format.
-
decimal
- Area address in decimal format.
-
E.F.G.H
- ID of the OSPF router at the remote end of the virtual link.
-
authentication-key
password
- Sets the password and encryption method. Only one encryption method can be active on an interface at a time. All OSPF packets transmitted on the interface contain this password. All OSPF packets received on the interface are checked for this password. If the password is not present, then the packet is dropped.
-
dead-interval
time
- How long a neighbor router waits for a hello packet from the current router before declaring the router down. This value must be the same for all routers and access servers that are attached to a common network. Valid values range from 3 through 65535 seconds. The default is 40 seconds.
-
hello-interval
time
- Time between hello packets that the router sends on an interface. The value must be the same for all routers and access servers that are attached to a common network. Valid values range from 1 through 65535 seconds. The default is 10 seconds.
-
md5-authentication
- Sets either MD5 key-activation wait time or key identifier.
- key-activation-wait-time
time
- Time before a newly configured MD5 authentication key is valid. This parameter provides a graceful transition from one MD5 key to another without disturbing the network. All new packets transmitted after the wait time ends will use the newly configured MD5 Key. OSPF packets that contain the old MD5 key are accepted for up to five minutes (300 seconds) after the new MD5 key is in operation. Valid values range from 0 through 14400 seconds. The default is 300 seconds.
- key-id
num
key
- The
num is a number between 1 and 255 which identifies the MD5 key being used. This parameter is required to differentiate among multiple keys defined on a device. When MD5 is enabled, the key is an alphanumeric password of up to 16 characters that is later encrypted and included in each OSPF packet transmitted. You must enter a password in this field when the system is configured to operate with either simple or MD5 authentication. By default, the MD5 authentication key is encrypted.
- retransmit-interval
time
- Time between Link State Advertisement (LSA) retransmissions for adjacencies belonging to the interface. Set this interval to a value larger than the expected round-trip delay between any two routers on the attached network. Valid values range from 0 through 3600 seconds. The default is 5 seconds.
- transmit-delay
time
- Estimated time required to send an LSA on the interface. This value must be an integer greater than zero. The age of each LSA in the update packet is incremented by the value of this parameter before transmission occurs. Valid values range from 0 through 3600 seconds. The default is 1 second.
Modes
OSPF router configuration mode
OSPF router VRF configuration mode
Usage Guidelines
The
no form of the command removes a virtual link.
Examples
The following example creates a virtual link for an area whose decimal address is 1, and where the ID of the OSPFv2 device at the remote end of the virtual link is 10.1.2.3.
device# configure terminal
device(config)# router ospf
device(config-router-ospf-vrf-default-vrf)# area 1 virtual-link 10.1.2.3
