From: Joe Mama (jsmith1234550@gmail.com)
Date: Wed Sep 19 2007 - 23:20:14 ART
Hello Cecil,
From a IGP design perspective, how does extending Area 0 give you more
options? Regardless of the IGP or OSPF area (OSPF, static, etc.), BGP
will use an IGP for redundancy if the loopback is used. As long as
the router has a path (IGP,static) in its routing table for the
neighbor, iBGP connections will be used over that path. I would only
extend Area 0 if it technically makes sense; any other area should do
unless specific things are done to the areas. If you used virutual
links or GREs then the path could actually take a sub-optimal path. I
would suggest that the optimal path is always kept in mind.
Just my 2 cents,
Joe
On 9/19/07, Cecil Wilson <Cecil.Wilson@flextronics.com> wrote:
> Joe
> as a general rule, I usually put all lo0 into OSPF area 0 for
> routers that touch area 0, this way I am extending the backbone (area
> 0) this gives me more peering options for ibgp do you see any down
> side to this practice.
> Any thoughts on this?
>
>
> 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
> Joe Mama
> Sent: Monday, September 17, 2007 11:46 AM
> To: Cecil Wilson
> Cc: Prashant Shukla; Ashok CCIE; ccielab@groupstudy.com
> Subject: Re: BGP over Frame-relay
>
> Cecil, Depending on what is being asked of you, peering via loopbacks
> may not be prefereable as it will take in to account multiple paths to
> reach the neighbor.
>
> With iBGP peers, this may be fine (and normally is), but with eBGP peers
> especially on a lab-type of scenario, would you want your AS to try
> multiple IGP paths to a neighbor in another AS or just use rdundant eBGP
> exit points (in a normal failover scenario)?
>
> So, via iBGP, loopback is a sound move most times. eBGP peering via a
> loopback may not always be the most sound move (especially in a lab-type
> of environment that will have IGPs knowing all of the routes of the
> other ASs via redistribution (rather than controlling all AS route
> propogation via eBGP.
>
> Joe
>
> On 9/12/07, Cecil Wilson <Cecil.Wilson@flextronics.com> wrote:
> > This maybe easy but which interface is consider the outgoing
> >
> > interface IP?
> >
> > Is it the directly connected interface? What happens when the
> >
> > router has multiple routes to a subnet?
> >
> > Thanks for all input
> >
> >
> >
> >
> >
> > 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
> >
> > Prashant Shukla
> >
> > Sent: Wednesday, September 12, 2007 8:49 AM
> >
> > To: 'Ashok CCIE'; ccielab@groupstudy.com
> >
> > Subject: RE: BGP over Frame-relay
> >
> >
> >
> > Ashok,
> >
> >
> >
> > It seems you are using the loopback to peer with your I/E-BGP peers
> > and
> >
> > the configs do not mention the "update-source" cmd.
> >
> >
> >
> > By default , if the update-source is not mentioned the peering is done
> >
> > using the outgoing interface's IP .
> >
> >
> >
> > Here it seems in the BGP peering the routers are expecting the source
> > of
> >
> > the BGP TCP connection to be interface IPs rather that loop backs.
> >
> > (default).
> >
> >
> >
> > Would recommend using update-source with peers and Im sure the peering
> >
> > will be up.
> >
> >
> >
> > Have burnt my hands in the past with same.
> >
> >
> >
> >
> >
> > Shukla.
> >
> > Cisco Systems.
> >
> > Scott Morris <swm@emanon.com> wrote: Take a look at "debug ip packet"
> >
> > perhaps and you may find that the packets are coming from an IP
> > address
> >
> > that the other side doesn't have listed in its neighbor table. (e.g.
> >
> > update-source)
> >
> >
> >
> >
> >
> > -----Original Message-----
> >
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> > Of
> >
> > Ashok CCIE
> >
> > Sent: Wednesday, September 12, 2007 7:27 AM
> >
> > To: ccielab@groupstudy.com
> >
> > Subject: BGP over Frame-relay
> >
> >
> >
> > Hi Team,
> >
> >
> >
> > I am configuring IBGP b/w loopback interfaces of two interfaces which
> >
> > are over Frame-relay. But my routers are not making any neighbor
> >
> > relationship.
> >
> > Why so?
> >
> >
> >
> > Config is here..
> >
> >
> >
> > R1
> >
> >
> >
> > router bgp 100
> >
> > no synchronization
> >
> > bgp router-id 2.2.2.1
> >
> > bgp log-neighbor-changes
> >
> > network 1.1.1.0 mask 255.255.255.0
> >
> > network 2.2.2.1 mask 255.255.255.255
> >
> > neighbor 2.2.2.2 remote-as 100
> >
> > neighbor 2.2.2.2 next-hop-self
> >
> > neighbor 2.2.2.3 remote-as 100
> >
> > neighbor 2.2.2.3 next-hop-self
> >
> > no auto-summary
> >
> >
> >
> > R2
> >
> >
> >
> > router bgp 100
> >
> > no synchronization
> >
> > bgp router-id 2.2.2.2
> >
> > bgp log-neighbor-changes
> >
> > network 1.1.1.0 mask 255.255.255.0
> >
> > network 2.2.2.2 mask 255.255.255.255
> >
> > neighbor 2.2.2.1 remote-as 100
> >
> > neighbor 2.2.2.1 ebgp-multihop 255
> >
> > no auto-summary
> >
> >
> >
> >
> >
> > Could you please help?
> >
> >
> >
> > Thanks,
> >
> > Ashok
> >
> >
> >
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