| Where allowed to run: All environments (*ALL) Threadsafe: No |
Parameters Examples Error messages |
The Add OSPF Virtual Link (ADDOSPFLNK) command configures a virtual link between two area border routers. To maintain backbone connectivity you must have all of your backbone routers interconnected either by permanent or virtual links. Virtual links are considered to be separate router interfaces connecting to the backbone area. Therefore, you are asked to specify many of the interface parameters when configuring a virtual link.
Virtual links can be configured between any two backbone routers that have an interface to a common non-backbone, non-stub area. Virtual links are used to maintain backbone connectivity and must be configured at both endpoints.
IPv4 and IPv6 OSPF virtual links can be added. The Neighbor router (LNKTMSARA) parameter value will determine whether the virtual link is an IPv4 or IPv6 OSPF virtual link.
Restrictions:
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| Keyword | Description | Choices | Notes |
|---|---|---|---|
| IPVERSION | IP version | *IPV4, *IPV6 | Required, Positional 1 |
| NGHRTR | Neighbor router | Character value | Required, Positional 2 |
| LNKTMSARA | Link transmission area | Character value | Required, Positional 3 |
| RETMSITV | Retransmission interval | 1-65535, 10 | Optional |
| TMSDLY | Transmission delay | 1-65535, 5 | Optional |
| ITVHELLO | Interval for hello | 1-255, 30 | Optional |
| DBEXCHTIMO | Database exchange timeout | 2-65535, 180 | Optional |
| INACTTIMO | Inactive router timeout | 2-65535, 40 | Optional |
| AUTHTYPE | Authentication type | *BACKBONE, *NONE, *MD5, *PASSWORD | Optional |
| AUTHVAL | Authentication values | Element list | Optional |
| Element 1: Authentication key identifier | 1-255 | ||
| Element 2: Authentication key | Character value |
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Specifies the IP version (IPv4 or IPv6) of the Virtual Link.
This is a required parameter.
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Specifies the router identifier of the neighbor (other endpoint).
This is a required parameter.
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Specifies a non-backbone, non-stub area through which the virtual link is configured. Virtual links can be configured between any two area border routers that have an interface to a common non-backbone and non-stub area. Virtual links must be configured in each of the link's two endpoints.
The IP version of the area must be the same as the virtual link.
This is a required parameter.
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Specifies the frequency (in seconds) of retransmitting link-state update packets, link-state request packets, and database description packets.
Note: If this parameter is set too low, needless retransmissions will occur that could affect performance and interfere with neighbor adjacency establishment. It should be set to a higher value for a slower machine.
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Specifies the estimated number of seconds that it takes to transmit link-state information over the virtual link. Each link-state advertisement has a finite lifetime of 1 hour. As each link-state advertisement is sent out from this virtual link, it will be aged by this configured transmission delay.
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Specifies the number of seconds between OSPF hello packets being sent out from this virtual link. The interval for hello should be set higher than the same value used on the intervening OSPF interfaces.
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Specifies the length of time that the database exchange process cannot exceed. If the interval elapses, the procedure will be restarted. This value must be larger than the interval for hello.
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Specifies the interval, in seconds, after not having received an OSPF hello, that the neighbor is declared to be down. This value must be larger than the interval for hello. The inactive router timeout should be set higher than the same value used on the intervening OSPF interfaces.
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Specifies the security scheme to be used over the virtual link. This parameter is ignored for OSPF IPv6 virtual links.
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Specifies the combination of parameters needed for cryptographic authentication.
Element 1: Authentication key identifier
Element 2: Authentication key
For *NONE authentication type, this parameter element is not required and is ignored if specified.
For authentication type *PASSWORD, this parameter element must specify a password for OSPF routers that are attached to this subnet. Valid values are any character string up to 8 characters in length coded within single quotation marks, or any hexadecimal string up to 8 bytes (16 hexadecimal characters) long beginning with X followed by the hexadecimal value enclosed in single quotation marks.
For authentication type *MD5, this parameter must specify the 16-byte MD5 authentication key for OSPF routers attached to this subnet. The standard method is with a 16-byte hexadecimal string beginning with X followed by the hexadecimal value enclosed in single quotation marks.
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Example 1:Adding an OSPF IPv4 Virtual Link
ADDOSPFLNK IPVERSION(*IPV4) NGHRTR('2.2.2.2')
LNKTMSARA('3.3.3.3')
This command adds a virtual link for neighbor router 2.2.2.2 with a link transmission area identifier of 3.3.3.3. To add a virtual link for IPv4, you need the router identifier over which the link will be established and the area identifier of the link transmission area. The system must be an area border router. The link transmission area must have been configured for IPv4 previously.
Example 2:Adding an OSPF IPv6 Virtual Link
ADDOSPFLNK IPVERSION(*IPV6) NGHRTR('62.62.62.62')
LNKTMSARA('63.63.63.63')
This command adds a virtual link for neighbor router 62.62.62.62 with a link transmission area identifier of 63.63.63.63. To add a virtual link for IPv6, you need the router identifier over which the link will be established and the area identifier of the link transmission area. The system must be an area border router. The link transmission area must have been configured for IPv6 previously.
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*ESCAPE Messages
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