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BGP question

Cisco has a proprietary BGP attribute called weight. Why do we need it? It seems to me it does similar things, but has less capability, than local preference?

2 ACCEPTED SOLUTIONS

Accepted Solutions
Cisco Employee

Re: BGP question

Weight is not a BGP attribute as it is not included in BGP update messages. It has only local significancy and has precedence over the local-preference.

Please refer to the following document for more information on the BGP Best Path Selection Process.

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094431.shtml

Hope this helps,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
Cisco Employee

Re: BGP question

I forgot to answer the "why do we need it" part of your question.

It is mainly used to override any attributes that might be received from any other peers, especially in the case of locally originated prefixes (via redistribution or network statement).

Hope this helps,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
3 REPLIES
Cisco Employee

Re: BGP question

Weight is not a BGP attribute as it is not included in BGP update messages. It has only local significancy and has precedence over the local-preference.

Please refer to the following document for more information on the BGP Best Path Selection Process.

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094431.shtml

Hope this helps,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
Cisco Employee

Re: BGP question

I forgot to answer the "why do we need it" part of your question.

It is mainly used to override any attributes that might be received from any other peers, especially in the case of locally originated prefixes (via redistribution or network statement).

Hope this helps,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
New Member

Re: BGP question

That answers my question. Thanks a lot!

Cheers,

Sarah

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