Re: Poison-reverse

Anantha,

I verified with IOS 12.3(14)T7 there is no command to disable this; however
we have with IOS XR for Cisco CRS-1 and Cisco XR 12000 Series Router you can
disable with *no poison-reverse* under interface config mode

HTH...
On Tue, Aug 18, 2009 at 8:13 AM, Anantha Subramanian Natarajan <
anantha.natarajan_at_gravitant.com> wrote:

> Thanks Tharak for the comments .
>
> Regards
> Anantha Subramanian Natarajan
>
> On Tue, Aug 18, 2009 at 6:22 AM, Abraham, Tharak <tharakabraham_at_gmail.com
> >wrote:
>
> > In *RIP *both Split Horizon and Poison reverse are ON by default under
> the
> > RIP process, and i dont know if there exist a command to turn the Poison
> > reverse OFF
> >
> > When talking about *RIPng*, Split Horizon is ON by default whereas Poison
> > reverse is OFF.
> > We could call this a flexible implementation.
> >
> > The combination of the above helps in tackling routing loops efficiently
> > though Poison reverse will create overhead in routing updates.(think
> > bandwidth)
> >
> > I would still Request for more comments on this..-:)
> >
> >
> >
> >
> > On Mon, Aug 17, 2009 at 11:07 PM, Anantha Subramanian Natarajan <
> > anantha.natarajan_at_gravitant.com> wrote:
> >
> >> Hi Pramod,
> >>
> >> Thanks for the detailed explanation.Is that mean,poison reverse is
> inbuild
> >> on the routing protocol when it is configured and there wouldn't be
> >> provision to enable or disable it ?.My basic curiousness for this
> question
> >> arrived from seeing a "poison-reverse"command under ipv6rip.I am
> >> wondering,
> >> is there a command related to poison-reverse on IPV4 distance vector
> >> routing
> >> protocol.
> >>
> >> Thanks
> >>
> >> Regards
> >> Anantha Subramanian Natarajan
> >>
> >> On Mon, Aug 17, 2009 at 3:57 PM, Pramod G <learn02earn_at_gmail.com>
> wrote:
> >>
> >> > Split horizon refers to the rule that information about a route will
> not
> >> be
> >> > sent out the same
> >> > interface or subinterface from which it was received (problem in
> >> multipoint
> >> > configurations)
> >> >
> >> > no ip split-horizon for RIP networks
> >> > no ip split-horizon as# for EIGRP networks
> >> >
> >> > Poison reverse The rule for poison reverse is to advertise a route
> out
> >> the
> >> > interface on
> >> > which it was received with an unreachable metric. Different routing
> >> > protocols employ this
> >> > rule at different times to control routing loops.
> >> >
> >> > The router sends a poison reverse update to remove a route and place
> >> > it in holddown. This is done to avoid a routing loop
> >> >
> >> > On Mon, Aug 17, 2009 at 4:16 PM, Abraham, Tharak <
> >> tharakabraham_at_gmail.com
> >> > > wrote:
> >> >
> >> >> Anantha,
> >> >>
> >> >> Distance vector protocols are/should be implemented with split
> horizon
> >> and
> >> >> poison reverse !
> >> >> Both are different concepts, but gives the best when it works
> together.
> >> >>
> >> >> Please refer to Jeff Doyle Vol 1, read through pages 89 and 90 (pdf)
> >> with
> >> >> the examples.
> >> >>
> >> >>
> >> >> Best Regards,
> >> >> Tharak Abraham
> >> >>
> >> >>
> >> >>
> >> >> On Mon, Aug 17, 2009 at 9:27 PM, Anantha Subramanian Natarajan <
> >> >> anantha.natarajan_at_gravitant.com> wrote:
> >> >>
> >> >> > Hi All,
> >> >> >
> >> >> > I have a question on poison-reverse,to activate or de-activate
> >> poison
> >> >> > reverse for a distance vector routing protocols in cisco router,do
> we
> >> >> have
> >> >> > a
> >> >> > specific command for the same.Otherwise it is enabled,when we
> enable
> >> >> > split-horizon or it is enabled by default for all distance vector
> >> >> routing
> >> >> > protocol.I am sure missing something totally basic.Kindly help me
> to
> >> >> > understand the same.
> >> >> >
> >> >> > Thanks
> >> >> >
> >> >> > Regards
> >> >> > Anantha Subramanian Natarajan
> >> >> >
> >> >> >
> >> >> > Blogs and organic groups at http://www.ccie.net
> >> >> >
> >> >> >
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Received on Tue Aug 18 2009 - 09:38:37 ART