Defining ip prefix lists – Brocade TurboIron 24X Series Configuration Guide User Manual
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Brocade TurboIron 24X Series Configuration Guide
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Filtering
The seq <seq-value> parameter is optional and specifies the community list sequence number. You
can configure up to 199 entries in a community list. If you do not specify a sequence number, the
software numbers them in increments of 5, beginning with number 5. The software interprets the
entries in a community list in numerical order, beginning with the lowest sequence number.
The deny | permit parameter specifies the action the software takes if a route community list
matches a match statement in this ACL. To configure the community-list match statements in a
route map, use the match community command. Refer to
“Matching based on community ACL”
The <community-num> parameter specifies the community type or community number. This
parameter can have the following values:
•
<num>:<num> – A specific community number
•
internet – The Internet community
•
no-export – The community of sub-ASs within a confederation. Routes with this community can
be exported to other sub-ASs within the same confederation but cannot be exported outside
the confederation to other ASs or otherwise sent to EBGP neighbors.
•
local-as – The local sub-AS within the confederation. Routes with this community can be
advertised only within the local subAS.
•
no-advertise – Routes with this community cannot be advertised to any other BGP4 routers at
all.
The <regular-expression> parameter specifies a regular expression for matching on community
names. For information about regular expression syntax, refer to
page 705. You can specify a regular expression only in an extended community ACL.
Defining IP prefix lists
An IP prefix list specifies a list of networks. When you apply an IP prefix list to a neighbor, the Layer
3 Switch sends or receives only a route whose destination is in the IP prefix list. You can configure
up to 100 prefix lists. The software interprets the prefix lists in order, beginning with the lowest
sequence number.
To configure an IP prefix list and apply it to a neighbor, enter commands such as the following.
TurboIron(config)#ip prefix-list Routesfor1020 permit 10.20.20.0/24
TurboIron(config)#router bgp
TurboIron(config-bgp-router)#neighbor 10.10.10.1 prefix-list Routesfor20 out
These commands configure an IP prefix list named Routesfor1020, which permits routes to
network 10.20.20.0/24. The neighbor command configures the Layer 3 Switch to use IP prefix list
Routesfor1020 to determine which routes to send to neighbor 10.10.10.1. The Layer 3 Switch
sends routes that go to 10.20.20.x to neighbor 10.10.10.1 because the IP prefix list explicitly
permits these routes to be sent to the neighbor.
Syntax: ip prefix-list <name> [seq <seq-value>] [description <string>] deny | permit
<network-addr>/<mask-bits> [ge <ge-value>] [le <le-value>]
The <name> parameter specifies the prefix list name. You use this name when applying the prefix
list to a neighbor.
The description <string> parameter is a text string describing the prefix list.