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This chapter describes the Cisco NX-OS unicast routing commands that begin with the letter N.
To specify a master group name, use the name command. To revert to the default setting, use the no form of this command.
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The name command changes a regular Hot Standby Redundancy Protocol (HSRP) group into a master group.
If you do not specify a name, a unique name is automatically generated.
This example shows how to specify a master group name:
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To enable the translation of Open Shortest Path First (OSPF) router IDs to host names, either by looking up the local hosts database or querying domain name server (DNS) names in IPv6, use the name-lookup command. To stop displaying OSPF router IDs as DNS names, use the no form of this command.
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The name-lookup command makes it easier to identify a device because it displays the device by name rather than by its router ID or neighbor ID.
This example shows how to enable the translation of OSPF router IDs to host names, either by looking up the local hosts database or querying DNS names in IPv6:
This example shows how to stop displaying OSPF router IDs as DNS names:
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Configures an Open Shortest Path First (OSPF) routing instance. |
To configure a BGP neighbor (router, vrf) and enter the neighbor configuration mode, use the neighbor command. To remove an entry, use the no form of this command.
neighbor { ip-addr | ip-prefix / length | ipv6-addr | ipv6-prefix / length } [ remote-as { as-num [. as-num ] | route-map name }
no neighbor { ip-addr | ip-prefix / length | ipv6-addr | ipv6-prefix / length } [ remote-as { as-num [. as-num ] | route-map name }]
Neighbor address-family configuration
Router bgp configuration
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Use the neighbor command to enter the BGP neighbor configuration mode. When you enter the neighbor command, the prompt changes to switch(config-router-neighbor)#.
From the BGP neighbor configuration mode, you can perform the following actions:
This command is ignored if the route-map keyword is used in the neighbor command.
Note You should enter this command under the guidance of Cisco technical support staff only.
The Cisco NX-OS software allows BGP sessions to use any operational interface for TCP connections, when you enter the update-source command in neighbor configuration mode. To restore the interface assignment to the closest interface, which is called the best local address, use the no form of this command.
You must use the update-source command must to enable IPv6 link-local peering for internal or external BGP sessions.
This example shows how to configure a single-hop eBGP peering session between two BGP peers that are reachable on the same network segment through a local loopback interfaces on each router:
This example shows how to source BGP TCP connections for the specified neighbor with the IP address of the loopback interface rather than the best local address:
This example shows how to source IPv6 BGP TCP connections for the specified neighbor in autonomous system 64496 with the global IPv6 address of loopback interface 0 and the specified neighbor in autonomous system 64498 with the link-local IPv6 address of Ethernet interface 2/1:
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To configure an Intermediate System-to-Intermediate System (IS-IS) network entity (NET) for the routing process, use the net command. To remove a NET, use the no form of this command.
NET network services access point (NSAP) name or address for the IS-IS routing process; see the “Usage Guidelines” section for additional information about valid values. |
Router configuration
VRF configuration
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An IS (intermediate system) is identified by an address known as a network access point (NASAP). The NSAP is divided up into three parts as specified by ISO/AI 10589:
A NET is an NSAP where the last byte is always the n-selector and is always zero. A NET can be from 8 to 20 bytes in length. The NET is formatted as follows: XX.AAAA.AAAA.AAAA[.AAAA].XX.
Under most circumstances, you should configure one NET only. It is possible to configure two or three NETs, but you should not configure more than one NET except for the following unusual circumstances:
Configuring multiple NETs in these two circumstances can be temporarily useful because multiple area addresses enable you to renumber an area individually as needed.
If you are using IS-IS to perform IP routing only (no connectionless network service routing is enabled), you must configure a NET to define the router ID and area ID.
This example shows how to configure a router with a NET which consists of the system ID 0000.0c11.1110 and area address 47.0004.0(1)04d.0001:
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To configure an IP prefix to advertise, use the network command. To remove the IP prefix to advertise, use the no form of this command.
network ip-addr | ip-prefix / length mask mask-num [ route-map name ]
no network ip-network | ip-prefix / length mask mask-num [ route-map name ]
Neighbor address-family configuration
Router bgp configuration
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The IP prefix to advertise is considered for bestpath and advertisement to peers only if a route of equal or more specificity is present in the routing table.
This example shows how to configure an IP prefix to advertise:
To specify that Border Gateway Protocol (BGP) routes are resolved using only next hops whose routes match specific characteristics, use the nexthop route-map command. To remove the route map, use the no form of this command.
Route map name. The name can be any alphanumeric string up to 63 characters. |
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Use the nexthop route-map command to configure route policy filtering for next hops.
BGP next-hop filtering allows you to specify that when a next-hop address is checked with the RIB, the underlying route for that next-hop address is passed through the route map. If the route map rejects the route, the next-hop address is treated as unreachable.
BGP marks all next hops that are rejected by the route policy as invalid and does not calculate the best path for the routes that use the invalid next-hop address.
This example shows how to configure a route map to filter the next-hop address:
switch(config)# route-map CHECK-BGP25 deny 10
switch(config-route-map)# match ip address prefix-list FILTER25
switch(config-route-map)# match source-protocol ospf-o1
switch(config-route-map)# exit
switch(config)# ip prefix-list FILTER25 seq 5 permit 0.0.0.0/0 le 25
switch(config)# router bgp 1.0
switch(config-router)# address-family ipv4 unicast
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Configures the delay timers for BGP next-hop address tracking. |
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Defines the conditions for redistributing routes from one routing protocol into another. |
To specify that Border Gateway Protocol (BGP) delay for triggering next-hop calculations, use the nexthop trigger-delay command. To set the trigger delay to the default value, use the no form of this command.
nexthop trigger-delay { critical delay | non-critical delay }
no nexthop trigger-delay { critical delay | non-critical delay }
Critical delay: 3000 milliseconds.
Noncritical delay: 10000 milliseconds.
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Use the nexthop trigger-delay command to modify when BGP processes next-hop address tracking events.
The non-critical delay value must always be set to at least equal or greater than the critical delay value.
The delay should be slightly higher than the time it takes for the Interior Gateway Protocol (IGP) to settle into a steady state after some event (IGP convergence time).
This example shows how to modify the next-hop address tracking delay:
switch(config)# router bgp 1.0
switch(config-router)# address-family ipv4 unicast
switch(config-router-af)# nexthop trigger-delay critical 5000 non-critical 20000
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To re-enable the sending of routing updates on an Intermediate System-to-Intermediate System (IS-IS) interface and activates only those interfaces that need adjacencies, use the no isis passive-interface command.
no isis passive-interface {level-1 | level-1-2 | level-2}
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This example shows how to re-enable sending of routing updates on an IS-IS interface and activates only those interfaces that need adjacencies:
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Allows all IS-IS interfaces to be set as passive by default. |