Dell Force10 E300, Configuration Manual, Page: 254 / 1262

254 | Border Gateway Protocol IPv4 (BGPv4)
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You can also use route maps to change this and other BGP attributes. For example, you can include the
following command in a route map to specify the next hop address:
Enable multipath
By default, the software allows one path to a destination. You can enable multipath to allow up to 16
parallel paths to a destination.
Use the following command in the CONFIGURATION ROUTER BGP mode to allow more than one path.
The
show ip bgp
network
command includes multipath information for that network.
Filter BGP routes
Filtering routes allows you to implement BGP policies. You can use either IP prefix lists, route maps,
AS-PATH ACLs or IP Community lists (via a route map) to control which routes are accepted and
advertised by the BGP neighbor or peer group. Prefix lists filter routes based on route and prefix length,
while AS-Path ACLs filter routes based on the Autonomous System number. Route maps can filter and set
conditions, change attributes, and assign update policies.
For inbound and outbound updates the order of preference is:
• prefix lists (using
neighbor distribute-list
command)
• AS-PATH ACLs (using
neighbor filter-list
command)
• route maps (using
neighbor route-map
command)
Prior to filtering BGP routes, you must create the prefix list, AS-PATH ACL, or route map to be used.
Command Syntax Command Mode Purpose
set weight
weight
CONFIG-ROUTE-MAP Sets weight for the route.
•
weight
range: 0 to 65535
Command Syntax Command Mode Purpose
maximum-paths
{
ebgp
|
ibgp
}
number
CONFIG-ROUTER-
BGP Enable multiple parallel paths.
•
number
range: 1 to 16
• Default is 1
Note: FTOS supports up to 255 characters in a set community statement inside a route map.
Note: With FTOS, you can create inbound and outbound policies. Each of the commands used for
filtering, has
in
and
out
parameters that must be applied. In FTOS, the order of preference varies
depending on whether the attributes are applied for inbound updates or outbound updates.