BGP Community Lists
BGP community list is a user defined BGP communites attribute list.
BGP community list can be used for matching or manipulating BGP
communities attribute in updates.
There are two types of community list. One is standard community
list and another is expanded community list. Standard community list
defines communities attribute. Expanded community list defines
communities attribute string with regular expression. Standard
community list is compiled into binary format when user define it.
Standard community list will be directly compared to BGP communities
attribute in BGP updates. Therefore the comparison is faster than
expanded community list.
| ip community-list standard name {permit|deny} community
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Command |
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This command defines a new standard community list. community
is communities value. The community is compiled into community
structure. We can define multiple community list under same name. In
that case match will happen user defined order. Once the
community list matches to communities attribute in BGP updates it
return permit or deny by the community list definition. When there is
no matched entry, deny will be returned. When community is
empty it matches to any routes.
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| ip community-list expanded name {permit|deny} line
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Command |
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This command defines a new expanded community list. line is a
string expression of communities attribute. line can include
regular expression to match communities attribute in BGP updates.
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| no ip community-list name
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Command |
| no ip community-list standard name
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Command |
| no ip community-list expanded name
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Command |
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These commands delete community lists specified by name. All of
community lists shares a single name space. So community lists can be
removed simpley specifying community lists name.
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| show ip community-list
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Command |
| show ip community-list name
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Command |
This command display current community list information. When
name is specified the specified community list's information is
shown.
# show ip community-list
Named Community standard list CLIST
permit 7675:80 7675:100 no-export
deny internet
Named Community expanded list EXPAND
permit :
# show ip community-list CLIST
Named Community standard list CLIST
permit 7675:80 7675:100 no-export
deny internet
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