Adds an entry to the BGP neighbor table in router configuration mode. To remove an entry from the table, use the
no
form of this command.
Specifying a neighbor with an autonomous system number that matches the autonomous system number
specified in the
router bgp global configuration
command identifies the neighbor as internal to the local
autonomous system. Otherwise, the neighbor is considered external.
Enabling or disabling dynamic capabilities
Syntax:
[no] neighbor
ipv4-addr
dynamic
Specifies whether to enable or disable dynamic capabilities.
BGP Dynamic Capabilities allow the communication of a change in a BGP peer’s capabilities without having to
restart the peering session. The BGP implementation is done on a per-peer basis and in such a way that dynamic
capabilities are supported as long as the BGP peer supports BGP Dynamic Capabilities. BGP advertises Dynamic
Capabilities in the OPEN message. If a BGP peer advertises support for BGP Dynamic Capabilities in the OPEN
message, then it turns on Dynamic Capabilities. Otherwise, the dynamic capabilities for this peer will be disabled.
BGP supports the following BGP Dynamic Capabilities:
• Graceful restart
• Route refresh
Specifying the IP address for local end of TCP connection with peer
Syntax:
[no] neighbor
ipv4-addr
updated-source
ipv4-addr
Specifies the IP address to be used on the local end of the TCP connection with the peer. This is the address of a
broadcast, NBMA or loopback interface and the local address of a point-to-point interface. For external peers, the
local address must be on an interface that is shared with the peer or with the peer’s gateway when a gateway is
used. A session with an external peer will be opened only when an interface with the appropriate local address
(through which the peer or gateway address is directly reachable) is operating. For internal peers, a peer session
will be maintained when any interface with the specified local address is operating. In any case, an incoming
connection will be recognized as a match for a configured peer only if it is addressed to the configured local
address.
Specifying the number of times the autonomous system can appear in an
AS path
Syntax:
[no] neighbor
ipv4-addr
allowas-in
num-loops
Specifies the number of times this autonomous system can appear in an AS path. When not configured, or when
using the
no
version of the command, the value of as-loops is set to its default value of 1.
Replacing occurrences of peer's AS with one from an export
Syntax:
[no] neighbor
ipv4-addr
as-override
Chapter 17 Border Gateway Protocol (BGP)
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