Re: Bgp update source loopback

hehehehehe.....:)

On Sat, May 15, 2010 at 11:02 PM, Alexei Monastyrnyi <alexeim73_at_gmail.com>wrote:

> Raghav,
> it would be a logical one. Playing in the lab is one thing, having such an
> inconsustency in a large environment would definitely cost you some troubles
> when something goes wrong and your night-watch engineer will have to
> troubleshot asking himself why on the Earth one peer uses physical interface
> while the other goes from the loopback :-)
> A nice approach is KISS, keep it simple stupid, as Occam would say "entities
> must not be multiplied beyond necessity" :-)
>
> HTH
> A.
>
>
> On 5/16/2010 3:37 PM, Raghav Bhargava wrote:
>
> Hi Alexei,
>
> I have tested this thing in a non MPLS environment. I think as long as you
> have NLRI reachibilty to the loopback it does not creates any inconsistency,
> but maybe i could be wrong.
>
> -Raghav
>
> On Sat, May 15, 2010 at 10:03 PM, Alexei Monastyrnyi <alexeim73_at_gmail.com>wrote:
>
>> Technically speaking sure, but that would introduce inconsistency and
>> certain level of unpredictability of this peering behavior. As many folks
>> have pointed out, peering from IP address of physical interface vs loopback
>> involves peer IP address reachbility and in case of MPLS environments also
>> proper labes assignments.
>>
>> The easiest way to understand is to play around with it on Dynamips, real
>> quick setup of 2 to 4 routers would do.
>>
>> HTH
>> A
>>
>>
>> On 5/16/2010 2:28 PM, Raghav Bhargava wrote:
>>
>> Since we all are talking about BGP update source loopback.
>>
>> Experts,
>>
>> Can we have below command on one Router and not on the other one and form
>> ibgp peering..:)
>>
>> neighbor x.x.x.x update-source-loopback x
>>
>>
>> Raghav
>>
>> On Sat, May 15, 2010 at 9:13 PM, Mustafa Yadav <mustafa.yadav_at_gmail.com> <mustafa.yadav_at_gmail.com>wrote:
>>
>>
>>
>> Good be a good troobleshooting question if it is not configured.
>>
>> On Sun, May 16, 2010 at 6:55 AM, Scott Morris <swm_at_emanon.com> <swm_at_emanon.com> wrote:
>>
>>
>>
>> If you decide not to, there will be lots of extra work in order to get
>>
>>
>> your
>>
>>
>> next-hop information correlating with your label path information....
>>
>>
>>
>>
>> Mustafa Yadav wrote:
>>
>> Hi All,
>>
>> I see i-bgp configuration in all mpls labs done by using update-source
>> loopback.Why do we have to use loopback as a source?If we do not use I
>>
>>
>> think
>>
>>
>> ibgp also come up.Is not that right?
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
>>
>> _______________________________________________________________________
>> Subscription information may be found at:
>>
>>
>> http://www.groupstudy.com/list/CCIELab.html
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
>> _______________________________________________________________________
>> Subscription information may be found at:http://www.groupstudy.com/list/CCIELab.html
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
> --
> Warm Regards
> Raghav
>
>

-- 
Warm Regards
Raghav
Blogs and organic groups at http://www.ccie.net