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Table Of Contents
N Commands
This chapter describes the Cisco NX-OS unicast routing commands that begin with the letter N.
neighbor
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}]
Syntax Description
Defaults
This command has no default settings.
Command Modes
Neighbor address-family configuration
Router bgp configurationSupported User Rolesnetwork-admin
vdc-adminCommand History
4.1(2)
Added support for the route-map keyword.
4.0(1)
This command was introduced.
Usage Guidelines
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:
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address-family—Configure an address-family (router, neighbor, vrf). See the address-family (BGP) command for information.
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This command is ignored if the route-map keyword is used in the neighbor command.
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Note
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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 command requires the Enterprise Services license.
Examples
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:
BGP Peer 1
switch(config)# interface loopback 1switch(config-if)# ip address 10.0.0.100 255.255.255switch(config-if)# exitswitch(config)# router bgp 64497switch(config-router)# neighbor 192.168.0.200 remote-as 64496switch(config-router-neighbor)# update-source loopback 1switch(config-router-neighbor)# disable-connected-checkBGP Peer 2
switch(config)# interface loopback 2switch(config-if)# ip address 192.168.0.200 255.255.255switch(config-if)# exitswitch(config)# router bgp 64496switch(config-router)# neighbor 10.0.0.100 remote-as 64497switch(config-router-neighbor)# update-source loopback 2switch(config-router-neighbor)# disable-connected-checkThis 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:
switch(config)# router bgp 64496switch(config-router)# neighbor 172.16.0.0 remote-as 64496switch(config-router-neighbor)# update-source Loopback0This 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:
switch(config)# router bgp 64497switch(config-router)# neighbor 3ffe::3 remote-as 64496switch(config-router-neighbor)# update-source Loopback0switch(config-router-neighbor)# neighbor fe80::2 remote-as 64498switch(config-router-neighbor)# update-source Ethernet 2/1Related Commands
net
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 net
no net net
Syntax Description
net
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.
Defaults
The defaults are as follows:
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Command Modes
Router configuration
VRF configurationSupported User Rolesnetwork-admin
vdc-adminCommand History
Usage Guidelines
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:
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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:
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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.
Examples
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:
switch(config)# router isis firstcompanyswitch(config-router)# net 47.0004.0(1)04d.0001.00
Related Commands
network
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]
Syntax Description
Defaults
This command has no default settings.
Command Modes
Neighbor address-family configuration
Router bgp configurationSupported User Rolesnetwork-admin
vdc-adminCommand History
Usage Guidelines
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.
Examples
This example shows how to configure an IP prefix to advertise:
switch(config-router-af)# network 2.2.2.2 mask 3.3.3.3 route-map testswitch(config-router-af)#nexthop route-map
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.
nexthop route-map name
no nexthop route-map name
Syntax Description
Defaults
None
Command Modes
Address-family configuration
Supported User Rolesnetwork-admin
vdc-adminCommand History
Usage Guidelines
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 command requires an Enterprise Services license.
Examples
This example shows how to configure a route map to filter the next-hop address:
switch# config t
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
switch(config-router-af)# nexthop route-map CHECK-BGP25
Related Commands
nexthop trigger-delay
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}
Syntax Description
Defaults
Critical delay: 3000 milliseconds.
Noncritical delay: 10000 milliseconds.Command Modes
Address-family configuratione
Supported User Rolesnetwork-admin
vdc-adminCommand History
Usage Guidelines
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 command requires an Enterprise Services license.
Examples
This example shows how to modify the next-hop address tracking delay:
switch# config t
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
Related Commands
feature bgp
Enables BGP.
nexthop route-map
Configures a route map for BGP next-hop address tracking.
