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doc: cleanup community list docs more

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Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>
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Quentin Young 2018-06-08 09:39:27 +00:00
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@ -1034,67 +1034,71 @@ is 4 octet long. The following format is used to define the community value.
it is considered as external BGP peer, so the route will not be announced to it is considered as external BGP peer, so the route will not be announced to
the peer. the peer.
When BGP communities attribute is received, duplicated communities value in the When the communities attribute is received duplicate community values in the
communities attribute is ignored and each communities values are sorted in attribute are ignored and value is sorted in numerical order.
numerical order.
.. _bgp-community-lists: .. _bgp-community-lists:
Community Lists Community Lists
^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^
Community lists are user defined lists of community attribute values. These
lists can be used for matching or manipulating the communities attribute in
UPDATE messages.
BGP community list is a user defined BGP communities attribute list. BGP There are two types of community list:
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 standard
another is expanded community list. Standard community list defines communities This type accepts an explicit value for the atttribute.
attribute. Expanded community list defines communities attribute string with
regular expression. Standard community list is compiled into binary format when expanded
user define it. Standard community list will be directly compared to BGP This type accepts a regular expression. Because the regex must be
communities attribute in BGP updates. Therefore the comparison is faster than interpreted on each use expanded community lists are slower than standard
expanded community list. lists.
.. index:: ip community-list standard NAME permit|deny COMMUNITY .. index:: ip community-list standard NAME permit|deny COMMUNITY
.. clicmd:: ip community-list standard NAME permit|deny COMMUNITY .. clicmd:: ip community-list standard NAME permit|deny COMMUNITY
This command defines a new standard community list. COMUNITY is This command defines a new standard community list. ``COMMUNITY`` is
communities value. The COMUNITY is compiled into community structure. We communities value. The ``COMMUNITY`` is compiled into community structure.
can define multiple community list under same name. In that case match will We can define multiple community list under same name. In that case match
happen user defined order. Once the community list matches to communities will happen user defined order. Once the community list matches to
attribute in BGP updates it return permit or deny by the community list communities attribute in BGP updates it return permit or deny by the
definition. When there is no matched entry, deny will be returned. When community list definition. When there is no matched entry, deny will be
COMUNITY is empty it matches to any routes. returned. When ``COMMUNITY`` is empty it matches to any routes.
.. index:: ip community-list expanded NAME permit|deny LINE .. index:: ip community-list expanded NAME permit|deny COMMUNITY
.. clicmd:: ip community-list expanded NAME permit|deny LINE .. clicmd:: ip community-list expanded NAME permit|deny COMMUNITY
This command defines a new expanded community list. COMUNITY is a This command defines a new expanded community list. ``COMMUNITY`` is a
string expression of communities attribute. COMUNITY can be a string expression of communities attribute. ``COMMUNITY`` can be a regular
regular expression (:ref:`bgp-regular-expressions`) to match expression (:ref:`bgp-regular-expressions`) to match the communities
the communities attribute in BGP updates. attribute in BGP updates.
.. index:: no ip community-list NAME .. deprecated:: 5.0
.. clicmd:: no ip community-list NAME It is recommended to use the more explicit versions of this command.
.. index:: no ip community-list standard NAME .. index:: ip community-list NAME permit|deny COMMUNITY
.. clicmd:: no ip community-list standard NAME .. clicmd:: ip community-list NAME permit|deny COMMUNITY
.. index:: no ip community-list expanded NAME When the community list type is not specified, the community list type is
.. clicmd:: no ip community-list expanded NAME automatically detected. If ``COMMUNITY`` can be compiled into communities
attribute, the community list is defined as a standard community list.
Otherwise it is defined as an expanded community list. This feature is left
for backward compatibility. Use of this feature is not recommended.
These commands delete community lists specified by NAME. All of
community lists shares a single name space. So community lists can be
removed simply specifying community lists name.
.. index:: show ip community-list .. index:: no ip community-list [standard|expanded] NAME
.. clicmd:: show ip community-list .. clicmd:: no ip community-list [standard|expanded] NAME
.. index:: show ip community-list NAME Deletes the community list specified by ``NAME``. All community lists share
.. clicmd:: show ip community-list NAME the same namespace, so it's not necessary to specify ``standard`` or
``expanded``; these modifiers are purely aesthetic.
This command displays current community list information. When NAME is .. index:: show ip community-list [NAME]
specified the specified community list's information is shown. .. clicmd:: show ip community-list [NAME]
Displays community list information. When ``NAME`` is specified the
specified community list's information is shown.
:: ::
@ -1126,43 +1130,28 @@ is called as named community lists.
.. index:: ip community-list (1-99) permit|deny COMMUNITY .. index:: ip community-list (1-99) permit|deny COMMUNITY
.. clicmd:: ip community-list (1-99) permit|deny COMMUNITY .. clicmd:: ip community-list (1-99) permit|deny COMMUNITY
This command defines a new community list. (1-99) is standard This command defines a new community list. The argument to (1-99) defines
community list number. Community list name within this range defines the list identifier.
standard community list. When `community` is empty it matches to
any routes.
.. index:: ip community-list (100-199) permit|deny COMMUNITY .. index:: ip community-list (100-199) permit|deny COMMUNITY
.. clicmd:: ip community-list (100-199) permit|deny COMMUNITY .. clicmd:: ip community-list (100-199) permit|deny COMMUNITY
This command defines a new community list. (100-199) is expanded This command defines a new expanded community list. The argument to
community list number. Community list name within this range defines (100-199) defines the list identifier.
expanded community list.
.. index:: ip community-list NAME permit|deny COMMUNITY
.. clicmd:: ip community-list NAME permit|deny COMMUNITY
When community list type is not specified, the community list type is
automatically detected. If COMMUNITY can be compiled into communities
attribute, the community list is defined as a standard community list.
Otherwise it is defined as an expanded community list. This feature is left
for backward compatibility. Use of this feature is not recommended.
.. _bgp-using-communities-in-route-map: .. _bgp-using-communities-in-route-map:
Using Communities in Route Maps Using Communities in Route Maps
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
In Route Map (:ref:`route-map`), we can match or set BGP In :ref:`route-map` we can match on or set the BGP communities attribute. Using
communities attribute. Using this feature network operator can this feature network operator can implement their network policy based on BGP
implement their network policy based on BGP communities attribute. communities attribute.
Following commands can be used in Route Map. The ollowing commands can be used in route maps:
.. index:: match community WORD .. index:: match community WORD exact-match [exact-match]
.. clicmd:: match community WORD .. clicmd:: match community WORD exact-match [exact-match]
.. index:: match community WORD exact-match
.. clicmd:: match community WORD exact-match
This command perform match to BGP updates using community list WORD. When This command perform match to BGP updates using community list WORD. When
the one of BGP communities value match to the one of communities value in the one of BGP communities value match to the one of communities value in
@ -1170,32 +1159,25 @@ Following commands can be used in Route Map.
happen only when BGP updates have completely same communities value happen only when BGP updates have completely same communities value
specified in the community list. specified in the community list.
.. index:: set community none .. index:: set community <none|COMMUNITY> additive
.. clicmd:: set community none .. clicmd:: set community <none|COMMUNITY> additive
.. index:: set community COMMUNITY This command sets the community value in BGP updates. If the attribute is
.. clicmd:: set community COMMUNITY already configured, the newly provided value replaces the old one unless the
``additive`` keyword is specified, in which case the new value is appended
to the existing value.
.. index:: set community COMMUNITY additive If ``none`` is specified as the community value, the communities attribute
.. clicmd:: set community COMMUNITY additive is not sent.
This command manipulate communities value in BGP updates. When
`none` is specified as communities value, it removes entire
communities attribute from BGP updates. When `community` is not
`none`, specified communities value is set to BGP updates. If
BGP updates already has BGP communities value, the existing BGP
communities value is replaced with specified `community` value.
When `additive` keyword is specified, `community` is appended
to the existing communities value.
.. index:: set comm-list WORD delete .. index:: set comm-list WORD delete
.. clicmd:: set comm-list WORD delete .. clicmd:: set comm-list WORD delete
This command remove communities value from BGP communities attribute. This command remove communities value from BGP communities attribute. The
The `word` is community list name. When BGP route's communities ``word`` is community list name. When BGP route's communities value matches
value matches to the community list `word`, the communities value to the community list ``word``, the communities value is removed. When all
is removed. When all of communities value is removed eventually, the of communities value is removed eventually, the BGP update's communities
BGP update's communities attribute is completely removed. attribute is completely removed.
.. _bgp-communities-example: .. _bgp-communities-example:
@ -2202,12 +2184,12 @@ Example of a session to an upstream, advertising only one prefix to it.
ip prefix-list pl-allowed-adv seq 5 permit 82.195.133.0/25 ip prefix-list pl-allowed-adv seq 5 permit 82.195.133.0/25
ip prefix-list pl-allowed-adv seq 10 deny any ip prefix-list pl-allowed-adv seq 10 deny any
A more complex example. With upstream, peer and customer sessions. Advertising A more complex example including upstream, peer and customer sessions
global prefixes and NO_EXPORT prefixes and providing actions for customer advertising global prefixes and NO_EXPORT prefixes and providing actions for
routes based on community values. Extensive use of route-maps and the 'call' customer routes based on community values. Extensive use is made of route-maps
feature to support selective advertising of prefixes. This example is intended and the 'call' feature to support selective advertising of prefixes. This
as guidance only, it has NOT been tested and almost certainly contains silly example is intended as guidance only, it has NOT been tested and almost
mistakes, if not serious flaws. certainly contains silly mistakes, if not serious flaws.
.. code-block:: frr .. code-block:: frr