Re: BGP TTL

Then buddy all OSPF update packets are sent with a TTL of 1 to their
directly connected neighbors , so when the neighbors receive the packet ,
decrement the TTL to 0 and drop the packet ahh. Naa this will not happen

TTL decrement will happen only on outbound .

On Fri, Oct 21, 2011 at 5:20 PM, Imran Ali <immrccie_at_gmail.com> wrote:

> Hi kid,
>
> regardsless of data plane or control pale TTL value is reduced .
>
> The moment any interface receives a packet the TTL will be reduced by 1 .
>
> On Fri, Oct 21, 2011 at 2:25 PM, CCIE KID <eliteccie_at_gmail.com> wrote:
>
> > Hi fellas,
> >
> > I am working on BGP and i find in sh ip bgp neighbor command, the
> incoming
> > TTL and the outgoing TTL . I understood the outgoing TTL is the one when
> > the
> > control plane packets are generated , the TTL in the IP Header will be
> 255.
> > I find the incoming TTL to 0 . Can anyone explain me what is actually
> meant
> > by incoming TTL.
>
>
>
> > My understanding is the incoming TTL is the when the
> > neighbor send u any BGP Control plane packet, the local router is
> expecting
> > this TTL value in the IP HEader. Am i right ?
> > So the incoming TTL valus is 0 in my case..
> >
>
> regardless of any operation , the TTL value is always present in ip header
> :-
>
> >
> > Router drops a packet with a TTL value of 0. So when the control plane
> > packet comes. it should be of TTL of 1.
> > TTL will be only decremented on the outgoing interface and not the
> incoming
> > interface. THe genreal logic says that the TTL of all control plane
> packets
> > of all IGPS will be 1 and so when a router receives this control plane
> > packet , it is destined to itself , it will update the OSPF or EIGRP RIB
> > and
> > in turn do the local computation for the best path .
> >
> > My question is whether the where does the TTL decrement happen ? My
> answer
> > is outbound and for any other control plane packet it will be destined to
> > itslef , so there will be no decrement in the TTL
> >
> > --
> > With Warmest Regards,
> >
> > CCIE KID
> > CCIE#29992 (Security)
> >
> >
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Received on Fri Oct 21 2011 - 17:36:50 ART