RE: BGP Best Path Selection

There is also something like oldest route ... im not sure ..

I think when a route is received from an ibgp neighbor then the next steps are
a bit different then when it is from ebgp neighbor ... is it true ?

Zeeshan

From: divinjohn_at_gmail.com
Date: Fri, 22 May 2009 20:25:54 +0530
Subject: Re: BGP Best Path Selection
To: bbartik_at_ipexpert.com
CC: zeeshan_dreamcatcher_at_hotmail.com; ccielab_at_groupstudy.com

Zeeshan ,

If Multipath is Enabled then multiple routes to the same destination are
installed provided all the previous steps checked and are found to be equal.
incase the multipath isnt enabled then Prefer the route that comes from the
BGP router with the lowest
                router ID.if the router ID is also the same.. then If the originator or
router ID is the same for multiple paths, prefer
                the path with the minimum cluster list length., then comes the lowest
neighbor IP address(interface IP not router-id)Thanking You

Yours Sincerely

Divin Mathew John
divinjohn_at_gmail.com

divin_at_dide3d.com
http://www.dide3d.com
+91 9945430983
+91 9846697191
+974 5008916
PGP PUBLIC KEY BLOCK @ http://www.dide3d.com/divin_Public_PGP_key.txt

On Fri, May 22, 2009 at 8:19 PM, Bryan Bartik <bbartik_at_ipexpert.com> wrote:

Zeeshan,

You are on step 8 right here:

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

The lowest metric to the next hop would be next. In order for multiple paths

to be selected, the metric to the next hops should be equal. If they are

equal then you will move onto the next stop where multiple paths can be

installed.

-hth

Bryan Bartik

CCIE #23707 (R&S), CCNP

Sr. Support Engineer - IPexpert, Inc.

URL: http://www.IPexpert.com

On Fri, May 22, 2009 at 8:14 AM, Zeeshan Sanaullah <

zeeshan_dreamcatcher_at_hotmail.com> wrote:

> Hello !

>

> I am a little confused with BGP Best Path Selection. Till step where ebgp

> routes are prefferd over ibgp everything is clear.

> But after that there is little confusion. Many docs and books are not much

> clear after that.

>

> Want to hear from experts a simple less confusing explanation from lets say

> that we are on step where router has to choose

> ebgp over ibgp route. Then can you explain a little about the multipath

> thing

> , if it is on or off ....

>

>

> Regards

>

> Zeeshan

>

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