Specifications

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6-22
Cisco Nexus 3000 Series NX-OS Unicast Routing Configuration Guide, Release 5.0(3)U2(2)
OL-25782-02
Chapter 6 Configuring Advanced BGP
Configuring Advanced BGP
Configuring Next-Hop Filtering
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.
To configure BGP next-hop filtering, use the following command in address-family configuration mode:
Disabling Capabilities Negotiation
You can disable capabilities negotiations to interoperate with older BGP peers that do not support
capabilities negotiation.
To disable capabilities negotiation, use the following command in neighbor configuration mode:
Configuring eBGP
This section includes the following topics:
• Disabling eBGP Single-Hop Checking, page 6-22
• Configuring eBGP Multihop, page 6-23
• Disabling a Fast External Failover, page 6-23
• Limiting the AS-path Attribute, page 6-24
• Configuring Local AS Support, page 6-24
Disabling eBGP Single-Hop Checking
You can configure eBGP to disable checking whether a single-hop eBGP peer is directly connected to
the local router. Use this option for configuring a single-hop loopback eBGP session between directly
connected switches.
Command Purpose
nexthop route-map name
Example:
switch(config-router-af)# nexthop
route-map nextHopLimits
Specifies a route map to match the BGP next-hop
route to. The name can be any case-sensitive,
alphanumeric string up to 63 characters.
Command Purpose
dont-capability-negotiate
Example:
switch(config-router-neighbor)#
dont-capability-negotiate
Disables capabilities negotiation. You must
manually reset the BGP sessions after configuring
this command.