Re: Poison-reverse

Hi Pramod,

 Wah great and thanks for the input.

Regards
Anantha Subramanian Natarajan

On Tue, Aug 18, 2009 at 8:38 AM, Pramod G <learn02earn_at_gmail.com> wrote:

> 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
>> >> >> >
>> >> >> >
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Received on Tue Aug 18 2009 - 09:39:04 ART