Re: BGP metrics [7:36596]
Chuck, Wouldn't it be safer to say that if a BGP speaking router learns a prefix from a peer that doesn't have an AS-path attribute (what you referenced as being originated from) then it is IBGP because bgp won't tag it's own as-path onto a prefix until it tries to go over a ebgp connectiong. Furthermore, when you set up your 'neighbor x.x.x.x remote-as yyy' your pretty much defining that routes learned from that neighbor are ibgp (if that yyy is the same as your yyy) or ebgp (if they're different). Tim On 27 Feb 2002 01:35:07 -0500, [EMAIL PROTECTED] (Chuck) wrote: how does the router know? I would imagine the router OS checks the BGP origin. If I am AS 559 and I receive a BGP route that originates in AS 559, it is either iBGP, or I have a loop. If AS 559 is the only AS in the AS path, it follows that it is an iBGP route, and therefore is assigned an AD of 200. make sense? Thom Castognalia wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... How does a router assign an iBGP AD vs. an eBGP AD? The iBGP AD is less preferred than EIGRP and the other interior RPs, is that correct? (one week until RS qual. exam) Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=36753t=36596 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: BGP metrics [7:36596]
I checked RFC 1771 just to be sure. You are correct that I should not have discussed this in terms of the AS-PATH Within the BGP update message there is a field defined as path attributes One of the sub fields of path attributes is the origin . bit settings within this sub field are the indicator if a route is iBGP, eBGP, or incomplete. The originating router sets these bits, I presume based on the nature of its neighbor relationship. In answer to the original post, the answer to these kinds of questions can usually be found within the published standard. The router, being a computer, merely processes data and produces information based upon the results of that processing. Chuck [EMAIL PROTECTED] (Timothy Ouellette) wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... Chuck, Wouldn't it be safer to say that if a BGP speaking router learns a prefix from a peer that doesn't have an AS-path attribute (what you referenced as being originated from) then it is IBGP because bgp won't tag it's own as-path onto a prefix until it tries to go over a ebgp connectiong. Furthermore, when you set up your 'neighbor x.x.x.x remote-as yyy' your pretty much defining that routes learned from that neighbor are ibgp (if that yyy is the same as your yyy) or ebgp (if they're different). Tim On 27 Feb 2002 01:35:07 -0500, [EMAIL PROTECTED] (Chuck) wrote: how does the router know? I would imagine the router OS checks the BGP origin. If I am AS 559 and I receive a BGP route that originates in AS 559, it is either iBGP, or I have a loop. If AS 559 is the only AS in the AS path, it follows that it is an iBGP route, and therefore is assigned an AD of 200. make sense? Thom Castognalia wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... How does a router assign an iBGP AD vs. an eBGP AD? The iBGP AD is less preferred than EIGRP and the other interior RPs, is that correct? (one week until RS qual. exam) Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=36761t=36596 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
BGP metrics [7:36596]
How does a router assign an iBGP AD vs. an eBGP AD? The iBGP AD is less preferred than EIGRP and the other interior RPs, is that correct? (one week until RS qual. exam) Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=36596t=36596 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: BGP metrics [7:36596]
how does the router know? I would imagine the router OS checks the BGP origin. If I am AS 559 and I receive a BGP route that originates in AS 559, it is either iBGP, or I have a loop. If AS 559 is the only AS in the AS path, it follows that it is an iBGP route, and therefore is assigned an AD of 200. make sense? Thom Castognalia wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... How does a router assign an iBGP AD vs. an eBGP AD? The iBGP AD is less preferred than EIGRP and the other interior RPs, is that correct? (one week until RS qual. exam) Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=36606t=36596 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
