what does this BGP AS expression stands for?^(4837_)+9800

Answered Question
Aug 21st, 2007
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please help me

Correct Answer by CSCO10892433 about 9 years 11 months ago

Hi, wlsi


No, the parenthese pair showed up on your question are matacharacters. They have special meaning and will not match the parenthese showed up on the AS-PATH attribute. To match a BGP confederation route which has perenthesis pair in the AS-path attribute, use \( and \) instead. This "\" prior to the "(" and ")" will cancel the special meaning of "(" and ")", and just match the character "(" and ")".


For example, if you want to match the following AS-PATH exactly


(65000)


use the following regular expression


^\(65000\)$


HTH

SSLIN


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mohammedmahmoud Tue, 08/21/2007 - 22:47
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Hi,


This means an AS-PATH coming from AS 4837, and having AS 4837 at least once and then AS 9800.


HTH,

Mohammed Mahmoud.

CSCO10892433 Tue, 08/21/2007 - 22:52
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Hi, wlsi


It match those routes with AS-path atrribute which is beginning with one or more 4837s (this means those routes come from AS 4837 and these routes have or have not been manupulated by AS pre-pending), followed by one 9800(this means AS 4837 accepts these routes from AS 9800), then followed by anything (and this means these routes might or might not be originated from AS 9800).


HTH

SSLIN

wlsj Tue, 08/21/2007 - 23:37
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is it possible for a BGP confederation route ?it is also with a pair of ()

Correct Answer
CSCO10892433 Wed, 08/22/2007 - 00:25
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  • Silver, 250 points or more

Hi, wlsi


No, the parenthese pair showed up on your question are matacharacters. They have special meaning and will not match the parenthese showed up on the AS-PATH attribute. To match a BGP confederation route which has perenthesis pair in the AS-path attribute, use \( and \) instead. This "\" prior to the "(" and ")" will cancel the special meaning of "(" and ")", and just match the character "(" and ")".


For example, if you want to match the following AS-PATH exactly


(65000)


use the following regular expression


^\(65000\)$


HTH

SSLIN


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