Huawei Quidway NetEngine80E Configuration Manual page 900

HUAWEI NetEngine80E/40E Router
Configuration Guide - IP Routing
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Multiple rules (permit or deny) can be specified in a filter. The relationship between theses rules
is "OR", which means that if a route meets one of the matching rules, the route matches the
AS_Path filter. The following part demonstrates the functions of AS_Path filters in different
scenarios.
Common Application Scenario
In Figure
Router A and Router C, between Router B and Router C, between Router B and Router D,
between Router C and Router D, and between Router D and Router E.
Issue 02 (2014-09-30)
Description
Indicates an escape
character.
8-8, EBGP peer relationships are established between Router A and Router B, between
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Example
A backslash "\" is used to disable special functions
of signs in regular expressions, such as the left
parenthesis "(" and right parenthesis ")" in an
AS_Confed_Sequence, the left bracket "[" and right
bracket "]" in an AS_Confed_Set, and the left brace
"{" and right brace "}" in an AS_Set.
l \(65002_ matches AS_Confed_Sequences that
begin with (65002 followed by a sign.
Specifically, \(65002_ matches AS_Confed_Se-
quences with 65002 as the leftmost AS number
(the number of the last AS through which a route
passes) or the routes sent by peers in AS 65002.
l \(.*_65003_.*\) matches AS_Confed_Sequen-
ces with 65003 or routes that pass through AS
65003.
l _65004\) matches AS_Confed_Sequences that
end with a sign followed by 65004). Specifically,
_65004\) matches AS_Confed_Sequences with
65004 as the rightmost AS number (the number
of the first AS through which a route passes) or
the routes that originate in AS 65004. _65004\)
and 65004\) have the same function.
8 BGP Configuration
875