Extreme Networks ExtremeWare XOS 10.1, Manual

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122 ExtremeWare XOS 10.1 Concepts Guide
Security
Autonomous System Expressions
The
AS-path
keyword uses a regular expression string to match against the AS path. Table 24 lists the
regular expressions that can be used in the match conditions for BGP AS path and community. Table 25
list examples of regular expressions and the AS paths they match.
nlri [<ipaddress> | any]/<mask-length> {exact};
nlri [<ipaddress> | any] mask <mask> {exact}; Where, <ipaddress> and <mask> are in dotted decimal
format, <mask-length> is an integer in the range [0 - 32].
Keyword
any
matches any IP address with a given (or
larger) mask/mask-length.
origin [igp | egp | incomplete]; IGP, EGP and incomplete are the BGP route origin values.
tag <number>; <number> is a four byte unsigned number.
route-origin [direct | static | icmp | egp | ggp | hello |
rip | isis | esis | cisco-igrp | ospf | bgp | idrp | dvmrp |
mospf | pim-dm | pim-sm | ospf-intra | ospf-inter |
ospf-as-external | ospf-extern-1 | ospf-extern-2 |
bootp | e-bgp | i-bgp | mbgp | i-mbgp | e-mbgp |
isis-level-1 | isis-level-2 | isis-level-1-external |
isis-level-2-external] Matches the origin (different from BGP route origin) of a
route.
A match statement "route-origin bgp" will match routes
whose origin are "I-bgp" or "e-bgp" or "I-mbgp" or "e-mbgp".
Similarly, the match statement "route-origin ospf" will match
routes whose origin is "ospf-inta" or "ospf-inter" or
"ospf-as-external" or "ospf-extern-1" or "ospf-extern-2"
Table 24: Autonomous System Regular Expression Notation
Character Definition
N As number
N
1
- N
2
Range of AS numbers, where N
1
and N
2
are AS numbers and N
1
< N
2
[N
x
... N
y
] Group of AS numbers, where N
x
and N
y
are AS numbers or a range of AS numbers
[^N
x
... N
y
] Any AS numbers other than the ones in the group
. Matches any number
^ Matches the beginning of the AS path
$ Matches the end of the AS path
– Matches the beginning or end, or a space
- Separates the beginning and end of a range of numbers
* Matches 0 or more instances
+ Matches 1 or more instances
? Matches 0 or 1 instance
{ Start of AS SET segment in the AS path
} End of AS SET segment in the AS path
( Start of a confederation segment in the AS path
) End of a confederation segment in the AS path
Table 25: Policy Regular Expression Examples
Attribute Regular Expression Example Matches
AS path is 1234 “1234” 1234
Table 23: Policy Match Conditions (continued)
Match Condition Description