From: Gregory Gombas (ggombas@gmail.com)
Date: Thu Sep 27 2007 - 14:38:45 ART
Shiran - there was no discussion of prefix lengths here. The routes
are all being sent with the same length prefix.
On 9/27/07, shiran guez <shiranp3@gmail.com> wrote:
> as far as make better route a shorter prefix match, I think that practical
> you cant unless you remove the longer prefix.
>
> because ALWAYS a longer prefix is better.
>
>
>
>
> On 9/27/07, Gregory Gombas <ggombas@gmail.com> wrote:
> >
> > Ben - I think Step 1 is correct but not step 2. As Cecil said ebgp has AD
> of 20.
> >
> > Now since it prefers the locally originated route it ignores the BGP
> route.
> >
> > Step 2 would be to look where that locally originated route came from,
> > in this case RIP, and then use the rip route.
> >
> > So only the RIP route makes it to the routing table. I guess BGP is
> > smart enough to say that I'm not sending the locally originated BGP
> > route to the route table because it should already be in the route
> > table by some other source (protocol,connected,static, etc...)
> >
> > Hopefully some CCIE's will put their 2 cents here...
> >
> > On 9/27/07, Cecil Wilson < Cecil.Wilson@flextronics.com> wrote:
> > > Seems a little confusing
> > > 1. locally origin routes will be select oover ebgp however in terms
> > > of AD
> > > EBGP 20
> > > IBGP 200
> > > RIP 120
> > >
> > > So in terms of AD external BGP routes should be selected over IBGP?
> > >
> > > Im I looking at it wrong?
> > >
> > >
> > > Cecil G. Wilson
> > > IT Network Services
> > > Office: (901) 215-2710
> > > Cell: (901) 601-6201
> > > cecil.wilson@flextronics.com
> > >
> > >
> > > -----Original Message-----
> > > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> > > Ben
> > > Sent: Thursday, September 27, 2007 10:23 AM
> > > To: Gregory Gombas
> > > Cc: Cisco certification
> > > Subject: Re: RIP is preferred over eBGP!
> > >
> > > Gregory,
> > >
> > > Step 1: Router B is faced with two BGP sources, ebgp and locally
> > > originated (redistributed from RIP).
> > >
> > > BGP decision process will pick the locally originated over the ebgp
> > > route (Wendel Odom)
> > >
> > > W - weight
> > > L - local preference
> > > L - locally originated
> > > A - AS path
> > >
> > > O - Origin
> > > M - MED
> > > N - Neighbor Type
> > > I - cannot remember :)
> > >
> > >
> > > Step 2: BGP administrative distance for locally originated is 200, for
> > > RIP 120. RIP therefore wins.
> > >
> > > In case I've got the sequence figured out wrongly, comments are welcome.
> > >
> > > Ben
> > >
> > >
> > >
> > >
> > >
> > >
> > > On 9/26/07, Gregory Gombas <ggombas@gmail.com> wrote:
> > > >
> > > > I'm seeing the following quirk in a production network:
> > > >
> > > > BGP-->
> > > > RIP-->
> > > > RTRA----------RTRB
> > > >
> > > > Router A is directly connected to router B and is sending the same
> > > > routes via RIP and eBGP.
> > > > Router B is also redistributing the RIP routes into BGP (but filtered
> > > > from sending back to A)
> > > >
> > > > When you look at the route table on RouterB, it shows the routes as
> > > > RIP routes!
> > > > You would think the eBGP learned routes would be preferred because of
> > > > lower AD.
> > > > But when I look at BGP table it shows the route originated locally and
> > >
> > > > thus preferred over eBGP learned route.
> > > > When I clear ip route the route is then shown as a eBGP route in the
> > > > routing table and BGP route table does not show the locally originated
> > >
> > > > route!
> > > >
> > > > Just wondering if anyone else has seen this...
> > > >
> > > >
> ______________________________________________________________________
> > > > _ Subscription information may be found at:
> > > > http://www.groupstudy.com/list/CCIELab.html
> > >
> > >
> _______________________________________________________________________
> > > Subscription information may be found at:
> > > http://www.groupstudy.com/list/CCIELab.html
> > >
> > > Legal Disclaimer:
> > > The information contained in this message may be privileged and
> confidential. It is intended to be read only by the individual or entity to
> whom it is addressed or by their designee. If the reader of this message is
> not the intended recipient, you are on notice that any distribution of this
> message, in any form, is strictly prohibited. If you have received this
> message in error, please immediately notify the sender and delete or destroy
> any copy of this message
> >
> >
> _______________________________________________________________________
> > Subscription information may be found at:
> > http://www.groupstudy.com/list/CCIELab.html
> >
>
>
>
> --
>
> Shiran Guez
> MCSE CCNP NCE1
> http://cciep3.blogspot.com
This archive was generated by hypermail 2.1.4 : Sat Oct 06 2007 - 12:01:16 ART