Defining a community acl – Brocade Communications Systems Layer 3 Routing Configuration ICX 6650 User Manual

Page 357

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Brocade ICX 6650 Layer 3 Routing Configuration Guide

339

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Filtering

The num:num parameter indicates a specific community number to filter. Use this parameter to
filter for a private (administrator-defined) community. You can enter up to 20 community numbers
with the same command.

If you want to filter for the well-known communities “LOCAL_AS”, “NO_EXPORT” or
“NO_ADVERTISE”, use the corresponding keyword (described below).

The internet keyword checks for routes that do not have the community attribute. Routes without a
specific community are considered by default to be members of the largest community, the
Internet.

The local-as keyword checks for routes with the well-known community “LOCAL_AS”. This
community applies only to confederations. The Layer 3 switch advertises the route only within the
sub-AS. For information about confederations, refer to

“Configuration notes for BGP4 autonomous

systems”

on page 320.

The no-advertise keyword filters for routes with the well-known community “NO_ADVERTISE”. A
route in this community should not be advertised to any BGP4 neighbors.

The no-export keyword filters for routes with the well-known community “NO_EXPORT”. A route in
this community should not be advertised to any BGP4 neighbors outside the local AS. If the router
is a member of a confederation, the Layer 3 switch advertises the route only within the
confederation. For information about confederations, refer to

“Configuration notes for BGP4

autonomous systems”

on page 320.

Defining a community ACL

To configure community ACL 1, enter a command such as the following.

Brocade(config)#ip community-list 1 permit 123:2

This command configures a community ACL that permits routes that contain community 123:2.

NOTE

Refer to

“Matching based on community ACL”

on page 345 for information about how to use a

community list as a match condition in a route map.

Syntax: ip community-list standard string [seq seq-value] deny | permit community-num

Syntax: ip community-list extended string [seq seq-value] deny | permit

community-num | regular-expression

The string parameter specifies the ACL name. (If you enter a number, the CLI interprets the number
as a text string.)

The standard or extended parameter specifies whether you are configuring a standard community
ACL or an extended one. A standard community ACL does not support regular expressions whereas
an extended one does. This is the only difference between standard and extended IP community
lists.

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.

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