Chapter 50
| IP Routing Commands
Border Gateway Protocol (BGPv4)
– 1115 –
Command Usage
Under standard routing practices, BGP will not accept a route sent from a neighbor
if the same AS number appears in the AS path more than once. This could indicate a
routing loop, and the route message would therefore be dropped. However, for
purposes of traffic engineering (such as degrading the preference for a certain
path), this command can be used to configure the number of times the same AS is
allowed re-appear in the AS path of a route received from a neighbor.
Example
Console(config-router)#neighbor 10.1.1.64 allowas-in 5
Console(config-router)#
neighbor
attribute-unchanged
This command configures certain route attributes to be kept unchanged for
transparent transmission to the specified neighbor. Use the no form to disable this
feature.
Syntax
[no] neighbor {ip-address | group-name} attribute-unchanged [as-path]
[med] [next-hop]
ip-address – IP address of a neighbor.
group-name – A BGP peer group containing a list of neighboring routers
configured with the neighbor peer-group command.
as-path – AS path attribute
med – Multi-Exit Discriminator (MED) attribute
next-hop – Next hop attribute
Command Mode
Router Configuration
Default Setting
Disabled
Command Usage
If this command is entered without specifying any route attributes, then all three
optional attributes are used.
Example
Console(config-router)#neighbor 10.1.1.64 attribute-unchanged
Console(config-router)#