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This chapter describes the Cisco NX-OS unicast routing commands that begin with the letter A.
To configure the capability of sending and receiving additional paths to and from the BGP peers, use the additional-paths command. To disable this feature, use the no form of this command.
additional-paths { receive | selection route-map map-name | send | install backup }
address-family configuration mode
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The additional-paths install backup command enables BGP to install the backup path to the routing table. This command is required to support the BGP PIC edge active-backup path scenario.
Note The additional-paths install backup command is supported only with IPv4 unicast address-families.
This example shows how to enable the additional paths send and receive capability for all neighbors under the specified address family for which this capability has not been disabled:
This example shows how to configure the additional paths selection under the specified address family:
This example shows how to configure the backup path to the routing table:
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To add a single, primary IP address to a virtual router, use the address command. To remove an IP address from a virtual router, use the no form of this command.
address ip-address [ secondary ]
Virtual router address (IPv4). This address should be in the same subnet as the interface IP address. |
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You can configure one virtual router IP address for a virtual router. If the configured IP address is the same as the interface IP address, this switch automatically owns the IP address. You can configure an IPv4 address only.
The master VRRP router drops the packets addressed to the virtual router's IP address because the virtual router is only intended as a next-hop router to forward packets. In NX-OS devices, some applications require that packets addressed to the virtual router's IP address be accepted and delivered. By using the secondary option to the virtual router IPv4 address, the VRRP router will accept these packets when it is the master.
This example shows how to configure a virtual router IP address:
This example shows how to remove all the IP addresses (primary and secondary) using a single command:
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Clears all the software counters for the specified virtual router. |
To enter the address family mode or a virtual routing and forwarding (VRF) address-family mode and configure submode commands for the Border Gateway Protocol (BGP), use the address-family command. To disable the address family submode for configuring routing protocols, use the no form of this command.
address-family { ipv4 | ipv6 } { multicast | unicast }
no address-family { ipv4 | ipv6 } { multicast | unicast }
Router configuration
Neighbor configuration
VRF configuration
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Use the address-family command to enter various address family configuration modes while configuring BGP routing. When you enter the address-family command from router configuration mode, you enable the address family and enter global address family configuration mode. The prompt changes to switch(config-router-af)#.
You must configure the address families if you are using route redistribution, address aggregation, load balancing, and other advanced features. IPv4 neighbor sessions support IPv4 unicast and multicast address families. IPv6 neighbor sessions support IPv6 unicast and multicast address families.
Note Beginning with Cisco NX-OS Release 6.2(8) you can configure the address-family ipv4 unicast command in an IPv6 session.
From the address family configuration mode, the following parameters are available:
Note This applies to IPv4 multicast or unicast and IPv6 multicast or unicast.
Note When enabled, the default-metric command applies a metric value of 0 to redistributed connected routes. The default-metric command does not override metric values that are applied with the redistribute command.
– direct route-map name —Specifies directly connected routes.
– eigrp AS-num route-map name —Specifies Enhanced Interior Gateway Protocol routes. Range: 1 to 65535.
– isis src-protocol route-map name —Specifies ISO IS-IS routes.
– ospf src-protocol route-map name —Specifies Open Shortest Path First (OSPF) routes.
– rip src-protocol route-map name —Specifies Routing Information Protocol (RIP) routes.
– static route-map name —Specifies static routes.
Use the neighbor command to enter neighbor address family configuration mode while configuring BGP routing. From the BGP neighbor configuration mode, you can perform the following actions:
This example shows how to place the router in global address family configuration mode for the IPv4 unicast address family:
This example shows how to activate IPv4 multicast for neighbor 192.0.2.1 and place the device in neighbor address family configuration mode for the IPv4 multicast address family:
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Configures the default metric for routes redistributed into BGP. |
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To configure an address family for the Enhanced Interior Gateway Routing Protocol (EIGRP), use the address-family command in router configuration mode.
address-family { ipv4 | ipv6 } unicast
Router configuration
Address family configuration
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This example shows how to set the IPv4 unicast address family for an EIGRP instance:
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Configures the default metric for routes redistributed into EIGRP. |
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To enter the address family mode or a virtual routing and forwarding (VRF) address-family mode and configure submode commands for the Intermediate System-to-Intermediate System Intradomain Routing Protocol (IS-IS), use the address-family command. To disable the address family submode for configuring routing protocols, use the no form of this command.
no address-family ipv4 unicast
Router configuration
VRF configuration
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Use the address-family command to enter various address family configuration modes while configuring IS-IS routing. When you enter the address-family command from configuration mode, you enable the address family and enter global address family configuration mode. The prompt changes to switch(config-router-af)#.
You must configure the address families if you are using route redistribution, address aggregation, load balancing, and other advanced features. IPv4 neighbor sessions support IPv4 unicast address families.
From the address family configuration mode, the following configuration modes are available:
Use the no adjacency-check command in address-family configuration mode to suppress the consistency checks for IPv6 IS-IS and allow an IPv4 IS-IS router to form an adjacency with a router running IPv4 IS-IS and IPv6. IS-IS will never form an adjacency between a router running IPv4 IS-IS only and a router running IPv6 only.
Use the no adjacency-check configuration mode command to suppress the IPv4 subnet consistency check and allow IS-IS to form an adjacency with other routers regardless of whether or not they have an IPv4 subnet in common. By default, IS-IS makes checks in hello packets for IPv4 address subnet matching with a neighbor.
Tip Use the debug isis adjacency packets command in privileged EXEC mode to check for adjacency errors. Error messages in the output may indicate where routers are failing to establish adjacencies.
– always —(Optional) Always advertises the default route.
– route-map name —(Optional) Specifies the name of the route-map to announce the default routes.
– level-1 —Distributes the interarea routes into level-1 of this IS-IS instance.
– level-2 —Distributes the interarea routes into level-2 of this IS-IS instance.
– into —Specifies from one level to another level.
– all —Distributes all route levels.
– route-map name —Prevents distribution of a specific route-map.
This example shows how to place the router in address family configuration mode and specify unicast address prefixes for the IPv4 address family:
This example shows how to redistribute directly connected routes into IS-IS. This example advertises only 10.1.0.0 into the IS-IS level-1 link-state PDU.
This example shows how to introduce IPv6 into an existing IPv4 IS-IS network. To ensure that the checking of hello packet checks from adjacent neighbors is disabled until all the neighbor routers are configured to use IPv6, enter the no adjacency-check command.
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To enter address family mode for the Open Shortest Path First version 3(OSPFv3) protocol, use the address-family command.
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This example shows how to enter the IPv6 unicast address family for an OSPFv3v3 instance:
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Configures the default metric for routes redistributed into OSPFv3. |
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To configure an address family for the Routing Information Protocol (RIP), use the address-family command in router configuration mode.
address-family { ipv4 | ipv6 } unicast
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This example shows how to set the IPv4 unicast address family for a RIP instance:
This example shows how to set the IPv6 unicast address family for a RIP instance:
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Configures the default metric for routes redistributed into RIP. |
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To enter address family configuration mode for configuring Intermediate System-to-Intermediate System (IS-IS) routing sessions that use standard IPv6 address prefixes, use the address-family ipv6 command. To disable the address family submode for configuring routing protocols, use the no form of this command.
no address-family ipv6 unicast
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Use the address-family ipv6 command to enter various address family configuration modes while configuring IS-IS routing. You must enter the address-family ipv6 command from router isis configuration mode. The prompt changes to switch(config-router-af)#:
switch(config-router-af)#
You must configure the address families if you are using route redistribution, address aggregation, load balancing, and other advanced features.
From the address family configuration mode, the following configuration modes are available:
Use the no adjacency-check command in in address-family configuration mode to suppress the consistency checks for IPv6 IS-IS and allow an IPv4 IS-IS router to form an adjacency with a router running IPv4 IS-IS and IPv6. IS-IS will never form an adjacency between a router running IPv4 IS-IS only and a router running IPv6 only.
Tip Use the debug isis adjacency packets command in privileged EXEC mode to check for adjacency errors. Error messages in the output may indicate where routers are failing to establish adjacencies.
– always —(Optional) Always advertises the default route.
– route-map name —(Optional) Specifies the name of the route-map to announce the default routes.
– level-1 —Distributes the interarea routes into level-1 of this IS-IS instance.
– level-2 —Distributes the interarea routes into level-2 of this IS-IS instance.
– into —Specifies from one level to another level.
– all —Distributes all route levels.
– route-map name —Prevents distribution of a specific route-map.
– transition —(Optional) Enables multitopology transition mode.
This example shows how to place the router in address family configuration mode and specify unicast address prefixes for the IPv6 address family:
This example shows how to ensure that the checking of hello packet checks from adjacent neighbors is disabled until all the neighbor routers are configured to use IPv6:
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To enable strict adjacency mode for the IPv4 and IPv6 address, use the adjacency-check command. To disable this feature, use the no form of this command.
address-family configuration mode
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This example shows how to configure the adjacency's protocol support consistency check:
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To configure Border Gateway Protocol (BGP) conditional advertisement, use the advertise-map command. To remove BGP conditional advertisement, use the no form of this command.
advertise-map adv-map { exist-map exist-rmap | non-exist-map nonexist-rmap }
BGP neighbor address-family command mode
network-admin
network-operator
vdc-admin
vdc-operator
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Use the advertise-map command to conditionally advertise selected routes. The routes or prefixes that BGP conditionally advertises are defined in two route maps, the adv-map and an exist-map or nonexist-map. The exist-map or nonexist-map specifies the prefix that the BGP tracks. The adv-map specifies the prefix that BGP advertises to the specified neighbor when the condition is met.
This example shows how to configure BGP conditional advertisement:
switch(config)# router bgp 65536
switch(config-router)# neighbor 192.0.2.2 remote-as 65537
switch(config-router-neighbor)# address-family ipv4 unicast
switch(config-router-neighbor-af)# advertise-map advertise exist-map exist
switch(config-router-neighbor-af)# exit
switch(config-router-neighbor)# exit
switch(config)# route-map advertise
switch(config-route-map)# match as-path pathList
switch(config-route-map)# exit
switch(config)# route-map exit
switch(config-route-map)# match ip address prefix-list plist
switch(config-route-map)# exit
switch(config)# ip prefix-list plist permit 209.165.201.0/27
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To specify the time interval between the advertisement packets that are being sent to other Virtual Router Redundancy Protocol (VRRP) routers in the same group, use the advertisement-interval command. To return to the default interval value of 1 second, use the no form of this command.
advertisement-interval seconds
Number of seconds between advertisement frames being sent. For IPv4, the range is from 1 to 255 seconds. |
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VRRP advertisements communicate the priority and state of the virtual router master. The advertisements are encapsulated in IP packets and are sent to the IPv4 multicast address that is assigned to the VRRP group.
VRRP uses a dedicated Internet Assigned Numbers Authority (IANA) standard multicast address (224.0.0.18) for VRRP advertisements. This addressing scheme minimizes the number of routers that must service the multicasts and allows test equipment to accurately identify VRRP packets on a segment. The IANA-assigned VRRP IP protocol number is 112.
This example shows how to specify an advertisement interval of 200 seconds for VRRP group 250:
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Clears all the software counters for the specified virtual router. |
To create a summary address in a Border Gateway Protocol (BGP) routing table, use the aggregate-address command. To remove the summary address, use the no form of this command.
aggregate-address address/length [ advertise-map map-name ] [ as-set ] [ attribute-map map-name ] [ summary-only ] [ suppress-map map-name ]
no aggregate-address address/mask-length [ advertise-map map-name ] [ as-set ] [ attribute-map map-name ] [ summary-only ] [ suppress-map map-name ]
The atomic aggregate attribute is set automatically when an aggregate route is created with this command unless the as-set keyword is specified.
Address-family configuration
Neighbor address-family configuration
Router BGP configuration
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You can implement aggregate routing in BGP and mBGP either by redistributing an aggregate route into BGP or mBGP, or by using the conditional aggregate routing feature.
Using the aggregate-address command with no keywords will create an aggregate entry in the BGP or mBGP routing table if any more-specific BGP or mBGP routes are available that fall within the specified range. (A longer prefix which matches the aggregate must exist in the RIB.) The aggregate route will be advertised as coming from your autonomous system and will have the atomic aggregate attribute set to show that information might be missing. (By default, the atomic aggregate attribute is set unless you specify the as-set keyword.)
Using the as-set keyword creates an aggregate entry using the same rules that the command follows without this keyword, but the path advertised for this route will be an AS_SET consisting of all elements contained in all paths that are being summarized. Do not use this form of the aggregate-address command when aggregating many paths, because this route must be continually withdrawn and updated as autonomous system path reachability information for the summarized routes changes.
Using the summary-only keyword not only creates the aggregate route (for example, 192.*.*.*) but also suppresses advertisements of more-specific routes to all neighbors. If you want to suppress only advertisements to certain neighbors, you may use the neighbor distribute-list command, with caution. If a more-specific route leaks out, all BGP or mBGP routers will prefer that route over the less-specific aggregate you are generating (using longest-match routing).
Using the suppress-map keyword creates the aggregate route but suppresses advertisement of specified routes. You can use the match clauses of route maps to selectively suppress some more-specific routes of the aggregate and leave others unsuppressed. IP access lists and autonomous system path access lists match clauses are supported.
Using the advertise-map keyword selects specific routes that will be used to build different components of the aggregate route, such as AS_SET or community. This form of the aggregate-address command is useful when the components of an aggregate are in separate autonomous systems and you want to create an aggregate with AS_SET, and advertise it back to some of the same autonomous systems. You must remember to omit the specific autonomous system numbers from the AS_SET to prevent the aggregate from being dropped by the BGP loop detection mechanism at the receiving router. IP access lists and autonomous system path access lists match clauses are supported.
Using the attribute-map keyword allows attributes of the aggregate route to be changed. This form of the aggregate-address command is useful when one of the routes forming the AS_SET is configured with an attribute such as the community no-export attribute, which would prevent the aggregate route from being exported. An attribute map route map can be created to change the aggregate attributes.
In This example, an aggregate BGP address is created in router configuration mode. The path advertised for this route will be an AS_SET consisting of all elements contained in all paths that are being summarized.
In This example, an aggregate BGP address is created in address family configuration mode and applied to the multicast database (SAFI) under the IP Version 4 address family. Because the summary-only keyword is configured, more-specific routes are filtered from updates.
Conditional Aggregation Example
In This example, a route map called MAP-ONE is created to match on an as-path access list. The path advertised for this route will be an AS_SET consisting of elements contained in paths that are matched in the route map.
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To enable authentication for an Open Shortest Path First (OSPF) area, use the area authentication command. To remove authentication for an area, use the no form of this command.
area area-id authentication [ message-digest ]
no area area-id authentication [ message-digest ]
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Use the area authentication command to configure the authentication mode for the entire OSPF area.
The authentication type and authentication password must be the same for all OSPF devices in an area. Use the ip ospf authentication-key command in interface configuration mode to specify this password.
If you enable MD5 authentication with the message-digest keyword, you must configure a password with the ip ospf message-digest-key command in interface configuration mode.
This example shows how to configure authentication for area 0 of OSPF routing process 201:
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Assigns a password for simple password authentication for OSPF. |
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To enable authentication of OSPFv3 packets on a per-interface basis at the Area level, use the area authentication ipsec command. To disable the authentication of OSPFv3 packets at the area level, use the no form of this command.
area area-num authentication ipsec spi spi auth [0|3|7] key
no authentication ipsec spi spi
Authentication algorithm. Its value can be md1 / sha1 / null. |
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Specifies that the authentication password is 3DES encrypted. |
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Specifies that the authentication password is Cisco type 7 encrypted. |
Router configuration (config-router).
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Before running this command, ensure that you have enabled the authentication package with the feature imp command.
The following example shows how to authenticate OSPFv3 packets for all interfaces under area 0:
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Enables authentication of the OSPFv3 packets for all interfaces under the router. |
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To specify a cost for the default summary route sent into an Open Shortest Path First (OSPF) stub or not-so-stubby area (NSSA), use the area default-cost command. To remove the assigned default route cost, use the no form of this command.
area area-id default-cost cost
no area area-id default-cost cost
The summary route cost is based on the area border router that generated the summary route.
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Use the area default-cost command on an Area Border Router (ABR) attached to a stub or NSSA to configure the metric for the summary default route generated by the ABR into the stub area.
This example shows how to set a default cost of 20 to stub network 192.0.2.0:
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To specify a cost for the default summary route sent into an Open Shortest Path First version 3(OSPFv3) stub or not-so-stubby area (NSSA), use the area default-cost command. To remove the assigned default route cost, use the no form of this command.
area area-id default-cost cost
no area area-id default-cost cost
The summary route cost is based on the area border router that generated the summary route.
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Use the area default-cost command on an Area Border Router (ABR) attached to a stub or NSSA to configure the metric for the summary default route generated by the ABR into the stub area.
This example shows how to set a default cost of 20 to stub network 33:
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To filter prefixes advertised in type 3 link-state advertisements (LSAs) between Open Shortest Path First (OSPF) areas of an Area Border Router (ABR), use the area filter-list command. To change or cancel the filter, use the no form of this command.
area area-id filter-list route-map map-name { in | out }
no area area-id filter-list route-map map-name { in | out }
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Use the area filter-list command to filter Type 3 LSAs. If you apply the route map with the in keyword, the route map filters all Type 3 LSAs originated by the ABR to this area, including Type 3 LSAs that originated as a result of the area range command in another area.
If you apply the route map with the out keyword, the route map filters all Type 3 LSAs that are advertised by the ABR to all other areas including Type 3 LSAs that originate locally as a result of the area range command configured in this area.
Cisco NX-OS implicitly denies any prefix that does not match an entry in the route map.
This example shows how to filter prefixes that are sent from all other areas to area 1:
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Defines the conditions for redistributing routes from one routing protocol into another or to enable policy routing. |
To filter prefixes advertised in type 3 link-state advertisements (LSAs) between Open Shortest Path First version 3 (OSPFv3) areas of an Area Border Router (ABR), use the area filter-list command. To change or cancel the filter, use the no form of this command.
area area-id filter-list route-map map-name { in | out }
no area area-id filter-list route-map map-name { in | out }
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Use the area filter-list command to filter Type 3 LSAs. If you apply the route map with the in keyword, the route map filters all Type 3 LSAs originated by the ABR to this area, including Type 3 LSAs that originated as a result of the area range command in another area.
If you apply the route map with the out keyword, the route map filters all Type 3 LSAs that are advertised by the ABR to all other areas including Type 3 LSAs that originate locally as a result of the area range command configured in this area.
Cisco NX-OS implicitly denies any prefix that does not match an entry in the route map.
This example shows how to filter prefixes that are sent from all other areas to area 1:
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Defines the conditions for redistributing routes from one routing protocol into another or to enable policy routing. |
To configure an area as an Open Shortest Path First (OSPF) not-so-stubby area (NSSA), use the area nssa command. To remove the NSSA area, use the no form of this command.
area area-id nssa [ default-information-originate [ route-map map-name ]] [ no-redistribution ] [ no-summary ] [ translate type7 [ always | never ] [ suppress-fa ]]
no area area-id nssa [ default-information-originate [ route-map map-name ]] [ no-redistribution ] [ no-summary ] [ translate type7 [ always | never ] [ suppress-fa ]]
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Use the area nssa command to create an NSSA area in an OSPF autonomous system. We recommend that you understand the network topology before configuring forwarding address suppression for translated LSAs. Suboptimal routing might result because there might be better paths to reach the destination’s forwarding address.
This example shows how to configure area 1 as an NSSA area:
This example shows how to configure area 1 as an NSSA area and translate Type 7 LSAs from area 1 to Type 5 LSAs, but not place the Type 7 forwarding address into the Type 5 LSAs. (OSPF places 0.0.0.0 as the forwarding address in the Type 5 LSAs.)
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Redistributes routes learned from one routing protocol to another routing protocol domain. |
To configure an area as an Open Shortest Path First version 3 (osPFv3) not-so-stubby area (NSSA), use the area nssa command. To remove the NSSA area, use the no form of this command.
area area-id nssa [ default-information-originate [ route-map map-name ]] [ no-redistribution ] [ no-summary ] [ translate type7 [ always | never ] [ suppress-fa ]]
no area area-id nssa [ default-information-originate [ route-map map-name ]] [ no-redistribution ] [ no-summary ] [ translate type7 [ always | never ] [ suppress-fa ]]
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Use the area nssa command to create an NSSA area in an OSPFv3 autonomous system. We recommend that you understand the network topology before configuring forwarding address suppression for translated LSAs. Suboptimal routing might result because there might be better paths to reach the destination’s forwarding address.
This example shows how to configure area 1 as an NSSA area:
This example shows how to configure area 1 as an NSSA area and translate Type 7 LSAs from area 1 to Type 5 LSAs, but not place the Type 7 forwarding address into the Type 5 LSAs. (OSPFv3 places 0.0.0.0 as the forwarding address in the Type 5 LSAs.)
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Redistributes routes learned from one routing protocol to another routing protocol domain. |
To consolidate and summarize routes at an Open Shortest Path First (OSPF) area boundary, use the area range command. To disable this function, use the no form of this command.
area area-id range ip-prefix [ not-advertise ] [ cost cost-value ]
no area area-id range ip-prefix [ not-advertise ] [ cost cost-value ]
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Use the area range command only with Area Border Routers (ABRs) to consolidate or summarize routes for an area. The ABR advertises that a single summary route is advertised to other areas and condenses routing information at area boundaries.
You can configure OSPF to summarize addresses for many different sets of address ranges by configuring multiple area range commands.
This example shows how to configure one summary route to be advertised by the ABR to other areas for all hosts on network 192.0.2.0:
To consolidate and summarize routes at an Open Shortest Path First version 3 (OSPFv3) area boundary, use the area range command. To disable this function, use the no form of this command.
area area-id range ipv6-prefix/length [ not-advertise ] [ cost cost-value ]
no area area-id range ivp6-prefix [ not-advertise ] [ cost cost-value ]
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Use the area range command only with Area Border Routers (ABRs) to consolidate or summarize routes for an area. The ABR advertises that a single summary route is advertised to other areas and condenses routing information at area boundaries.
You can configure OSPFv3 to summarize addresses for many different sets of address ranges by configuring multiple area range commands.
This example shows how to configure one summary route to be advertised by the ABR to other areas for all hosts on network 2001:0DB8::/32:
To define an area as an Open Shortest Path First (OSPF) stub area, use the area stub command. To remove the area, use the no form of this command.
area area-id stub [ no-summary ]
no area area-id stub [no-summary]
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Use the area stub command to configure all devices attached to the stub area. Use the area default-cost command on an area border router (ABR) attached to the stub area. The area default-cost command provides the metric for the summary default route generated by the ABR into the stub area.
To further reduce the number of link-state advertisements (LSAs) sent into a stub area, you can configure the no-summary keyword on the ABR to prevent it from sending Summary LSAs (Type 3 LSAs3) into the stub area.
This example shows how to create stub area 33 in OSPF 209:
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Specifies a cost for the default summary route sent into a stub area. |
To define an area as an Open Shortest Path First version 3 (OSPFv3) stub area, use the area stub command. To remove the area, use the no form of this command.
area area-id stub [ no-summary ]
no area area-id stub [no-summary]
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Use the area stub command to configure all devices attached to the stub area. Use the area default-cost command on an area border router (ABR) attached to the stub area. The area default-cost command provides the metric for the summary default route generated by the ABR into the stub area.
To further reduce the number of link-state advertisements (LSAs) sent into a stub area, you can configure the no-summary keyword on the ABR to prevent it from sending Summary LSAs (Type 3 LSAs3) into the stub area.
This example shows how to create stub area 33 in OSPFv3 209:
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Specifies a cost for the default summary route sent into a stub area. |
To define an Open Shortest Path First (OSPF) virtual link, use the area virtual-link command. To remove a virtual link, use the no form of this command.
area area-id virtual-link router-id
no area area-id virtual-link router-id
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Use the area virtual-link command to establish a virtual link from a remote area to the backbone area. In OSPF, all areas must be connected to a backbone area. If the connection to the backbone is lost, it can be repaired by establishing a virtual link.
Use the area virtual-link command to enter the virtual link configuration mode where you can use the following commands:
See each command for syntax and usage details.
You must configure both sides of a virtual link with the same area ID and the corresponding virtual link neighbor router ID. To see the router ID, use the show ip ospf neighbors command in any mode.
This example shows how to establish a virtual link between two devices, A, and B, with default values for all optional parameters:
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Assigns a password to be used by neighboring routers that are using the simple password authentication of OSPF. |
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Configures the retransmit interval for an OSPF virtual link. |
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To define an Open Shortest Path First version 3 (osPFv3) virtual link, use the area virtual-link command. To remove a virtual link, use the no form of this command.
area area-id virtual-link router-id
no area area-id virtual-link router-id
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Use the area virtual-link command to establish a virtual link from a remote area to the backbone area. In OSPFv3, all areas must be connected to a backbone area. If the connection to the backbone is lost, it can be repaired by establishing a virtual link.
Use the area virtual-link command to enter the virtual link configuration mode where you can use the following commands:
See each command for syntax and usage details.
You must configure both sides of a virtual link with the same area ID and the corresponding virtual link neighbor router ID. To see the router ID, use the show ospfv3 neighbors command in any mode.
This example shows how to establish a virtual link between two devices, A, and B, with default values for all optional parameters:
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Configures the retransmit interval for an OSPFv3 virtual link. |
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To configure the autonomous system number (ASN) notation to asdot, use the as-format asdot command. To delete the ASN notation configuration, use the no form of this command.
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This example shows how to configure the ASN notation to asdot:
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To configure an authentication for the Gateway Load Balancing Protocol (GLBP), use the authentication command. To disable authentication, use the no form of this command.
authentication { text string | md5 { key-string [ encrypted ] key | key-chain name-of-chain }}
no authentication { text string | md5 { key-string [ 0 | 7 ] key | key-chain name-of-chain }}
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To ensure interoperation, you must configure the same authentication method on all the gateways that are members of the same GLBP group. A gateway ignores all GLBP messages that contain the wrong authentication information.
This example shows how to configure stringxyz as the authentication string for GLBP group 10:
This example shows how to configure GLBP to use the key chain “AuthenticateGLBP” to obtain the current live key and key ID for MD5 authentication:
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To configure authentication for the Hot Standby Router Protocol (HSRP), use the authentication command. To disable authentication, use the no form of this command.
authentication { text string | md5 { key-chain key-chain | key-string { 0 | 7 } text [ timeout seconds ]}}
no authentication { text string | md5 { key-chain key-chain | key-string { 0 | 7 } text [ timeout seconds ]}}
HSRP configuration or HSRP template mode
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Use the authentication text command to prevent misconfigured routers from participating in HSRP groups that they are not intended to participate in. The authentication string is sent unencrypted in all HSRP messages. The same authentication string must be configured on all routers in the same group to ensure interoperation. HSRP protocol packets that do not authenticate are ignored.
This example shows how to configure an authentication string for HSRP group 2:
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To specify the authentication type for an Open Shortest Path First (OSPF) virtual link, use the authentication command. To remove the authentication type for a virtual link, use the no form of this command.
authentication [ key-chain key-name | message-digest | null ]
Defaults to password authentication if you configure authentication with none of the optional keywords.
OSPF virtual link configuration
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Use the authentication command in virtual link configuration mode to configure the authentication method used on the virtual link. Use the message-diges t keyword to configure MD5 message digest authentication and use the message-digest-key command to complete this authentication configuration. Use the key-chain keyword to configure password authentication using key chains and use the key chain command to complete this authentication configuration. Use the authentication command with no keywords to configure a password for the virtual link, and use the authentication-key command to complete this authentication configuration.
This example shows how to enable message-digest authentication:
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Assigns a password to be used by neighboring routers that are using the password authentication of OSPF. |
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To configure an authentication for the Virtual Router Redundancy Protocol (VRRP), use the authentication command. To disable authentication, use the no form of this command.
Selects to use simple text password of up to 8 alphanumeric characters. |
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This example shows how to configure md5 authentication for VRRP:
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Clears all the software counters for the specified virtual router. |
To enable authentication for the Enhanced Interior Gateway Routing Protocol (EIGRP) packets and to specify the set of keys that can be used on an interface, use the authentication key-chain command. To prevent authentication, use the no form of this command.
authentication key-chain name-of-chain
no authentication key-chain name-of-chain
Router configuration
Address family configuration
Router VRF configuration
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Set the authentication mode using the authentication mode command in VRF configuration mode. You must separately configure a key chain using the key-chain command to complete the authentication configuration for an interface.
This example shows how to configure the interface to accept and send any key that belongs to the key-chain trees:
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Enables authentication for EIGRP and specifies the set of keys that can be used on an interface. |
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Creates a set of keys that can be used by an authentication method. |
To enable authentication for Intermediate System-to-Intermediate System (IS-IS), use the authentication key-chain configuration mode command. To disable such authentication, use the no form of this command.
authentication key-chain auth-key { level-1 | level-2 }
no authentication key-chain auth-key { level-1 | level-2 }
No key chain authentication is provided for IS-IS packets at the router level.
Router configuration
VRF configuration
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If no key chain is configured with the authentication key-chain command, no key chain authentication is performed.
Key chain authentication could apply to clear text authentication or MD5 authentication. The mode is determined by the authentication mode command.
Only one authentication key chain is applied to IS-IS at one time. For example, if you configure a second authentication key-chain command, the first authentication key chain is overridden.
You can specify authentication for an individual IS-IS interface by using the isis authentication key-chain command.
This example shows how to configure IS-IS to accept and send any key belonging to the key chain named site1:
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To specify the type of authentication used in the Enhanced Interior Gateway Routing Protocol (EIGRP) packets, use the authentication mode command. To remove authentication, use the no form of this command.
Router configuration
Address family configuration
VRF configuration
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This example shows how to configure the interface to use MD5 authentication:
To specify for the Intermediate System-to-Intermediate System (IS-IS) instance that authentication is performed only on IS-IS packets being sent (not received), use the authentication-check configuration mode command. To configure for the IS-IS instance that if authentication is configured at the router level, such authentication be performed on packets being sent and received, use the no form of this command.
authentication-check { level-1 | level-2 }
If authentication is configured at the router level, it applies to IS-IS packets being sent and received.
Router configuration
VRF configuration
Enter the authentication-check command before configuring the authentication mode and authentication key chain. Entering the authentication-check command allows the routers to have more time for the keys to be configured on each router if authentication is inserted only on the packets being sent, not checked on packets being received. After you enter the authentication-check command on all communicating routers, enable the authentication mode and key chain on each router. Then enter the no authentication-check command to disable the command.
This command could apply to clear text authentication or Message Digest 5 (MD5) authentication. The mode is determined by the authentication mode command.
You can specify authentication for an individual IS-IS interface by using the isis authentication-check { level-1 | level-2 } interface configuration mode command.
This example shows how to configure IS-IS level-1 packets to use clear text authentication on packets being sent (not received):
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Enables authentication on IS-IS packets being sent (not received) from a specific interface. |
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To enable authentication of OSPFv3 packets on a per-interface basis at the Router level, use the authentication ipsec command. To disable the authentication of OSPFv3 packets, use the no form of this command.
authentication ipsec spi spi auth [0|3|7] key
no authentication ipsec spi spi
Authentication algorithm. Its value can be md1 / sha1 / null. |
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Specifies that the authentication password is 3DES encrypted. |
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Specifies that the authentication password is Cisco type 7 encrypted. |
Router configuration (config-router).
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Before running this command, ensure that you have enabled the authentication package with the feature imp command.
The following example shows how to authenticate OSPFv3 packets using md5, at the Router level for default VRF:
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Enables authentication of the OSPFv3 packets for all interfaces under the area. |
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To assign a password to be used by an Open Shortest Path First (OSPF) virtual link, use the authentication-key command. To remove a previously assigned OSPF password, use the no form of this command.
authentication-key [ 0 | 3 ] password
Any continuous string of characters that can be entered from the keyboard up to 8 bytes. |
OSPF virtual link configuration
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Use the authentication-key command to configure the password for password authentication on an OSPF virtual link. All devices on the same virtual link must have the same password to be able to exchange OSPF information.
This example shows how to enable the authentication key with the string yourpass:
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To specify the type of authentication used in Intermediate System-to-Intermediate System (IS-IS) packets for the IS-IS instance, use the authentication-type configuration mode command. To restore clear text authentication, use the no form of this command.
authentication-type { cleartex t | md5 } [ level-1 | level-2]
No authentication is provided for IS-IS packets at the router level by use of this command.
Router configuration
VRF configuration
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If you do not enter the level-1 or level-2 keywords, the mode applies to both levels.
You can specify the type of authentication and the level to which it applies for a single IS-IS interface, rather than per IS-IS instance, by using the authentication-type command.
You can specify authentication type for an individual IS-IS interface by using the isis authentication-type { cleartext | md5 } [ level-1 | level-2 ] interface configuration mode command.
This example shows how to configure the IS-IS instance that Message Digest 5 (MD5) authentication is performed on level-1 packets:
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Specifies the authentication type for an individual IS-IS interface. |
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To control how Open Shortest Path First (OSPF) calculates default metrics for an interface, use the auto-cost command. To assign the default reference bandwidth of 40Gb/s, use the no form of this command.
auto-cost reference-bandwidth bandwidth [Gbps | Mbps]
no auto-cost reference-bandwidth
40 Gb/s. The bandwidth defaults to Gb/s if you do not specify the Gpbs or Mbps keyword.
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Use the auto-cost command to set the reference bandwidth used by the OSPF cost-metric calculation.
The value set by the ip ospf cost command overrides the cost that results from the auto-cost command.
This example shows how to set the reference bandwidth for all local interfaces in an OSPF instance:
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Explicitly specifies the cost of sending a packet on an interface. |
To control how Open Shortest Path First version 3 (OSPFv3) calculates default metrics for an interface, use the auto-cost command. To assign the default reference bandwidth of 40Gb/s, use the no form of this command.
auto-cost reference-bandwidth bandwidth [Gbps | Mbps]
no auto-cos t reference-bandwidth
40 Gb/s. The bandwidth defaults to Gb/s if you do not specify the Gpbs or Mbps keyword.
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Use the auto-cost command to set the reference bandwidth used by the OSPFv3 cost-metric calculation.
The value set by the ipv6 ospfv3 cost command overrides the cost that results from the auto-cost command.
This example shows how to set the reference bandwidth for all local interfaces in an OSPFv3 instance:
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Explicitly specifies the cost of sending a packet on an interface. |
To configure the autonomous system number for an Enhanced Interior Gateway Routing Protocol (EIGRP) address family, use the autonomous-system command. To revert to default, use the no form of this command.
no autonomous-system as-number
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Use the autonomous-system command to set a common AS number for all EIGRP instances in an address family.
This example shows how to set an AS number for EIGRP for IPv6 unicast:
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