From: Hobbs (deadheadblues@gmail.com)
Date: Fri Feb 13 2009 - 14:22:13 ARST
I agree with Andrew but I would like to bring up some other things
that I find worth mentioning.
I think the explanation in the doc CD is a little misleading. The
packet WILL be forwarded if the TTL is EQUAL to the
threshold...provided you look at the TTL after the local router
decremented it.
That is the dilemma:
1) 13 when the router receives it (12 when it forwards)
2) 13 when the router fowards it (14 when it receives)
Now, the tasks states that all packets of TTL 12 and lower must be
dropped (less than 13).
From the doccd:
"Only multicast packets with a TTL value greater than the threshold
are forwarded out the interface."
Anyways, I think 13 is correct, but I if you follow the doccd, you may
come away with 12...
Am I making sense?
On Fri, Feb 13, 2009 at 7:42 AM, ALL From_NJ <all.from.nj@gmail.com> wrote:
> Hello Ruhann,
>
> Here is the link from the doc CD (watch the ugly word wrap):
> http://www.cisco.com/en/US/docs/ios/ipmulti/command/reference/imc_04.html#wp1011911
>
> ip multicast ttl-threshold xyz
>
> If the interface should NOT forward anything less than 13, then I would
> think this command applies, and the value should be listed as 13.
>
> Would appreciate your thoughts and comments as this is how I interpret the
> question. HTH,
>
> Andrew Lee Lissitz
>
>
>
>
>
> On Fri, Feb 13, 2009 at 2:59 AM, Ruhann <groupstudy@ru.co.za> wrote:
>
>> Hello poeples
>>
>> When a question is worded as follow:
>>
>> "In order to prevent multicast feeds from looping around the network,
>> configure R1 so that it does not send any multicast traffic out its
>> FastEthernet interface that has a TTL of less than 13."
>>
>> My understanding of TTL scoping with regard to the interface is
>> If the Packet TTL >= Interface TTL, then the packet is forwarded
>> If the Packet TTL < Interface TTL, then the packet is dropped
>>
>> But I cant make sense of this question.
>> Should I configure the Multicast TTL Threshold in the interface to be 12 or
>> 13?
>>
>> Your assistance would be appreciated
>> <ruhann>
>>
>>
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>
>
> --
> Andrew Lee Lissitz
> all.from.nj@gmail.com
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
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