On 8/1/14, 12:47 PM, "Juliusz Chroboczek" <[email protected]>
wrote:

>> Given the current RIPng standard timers, it could also be argued that
>> RIPng, as specified, doesn't meet the convergence requirements.
>
>>    Minimising convergence time should be a goal in any routed
>>    environment.  It is reasonable to assume that convergence time should
>>    not be significantly longer than network outages users are accustomed
>>    to should their CER reboot.
>
>Detecting a dead router in the absence of an explicit retraction takes one
>minute, worst case, 45 seconds average.  After that, convergence happens
>in 30 seconds, worst case, if you're using triggered updates.  Assuming
>you're also doing split horizon, typical convergence times are on the
>order of 4 seconds in many reasonable topologies.  (Note that Quagga's
>RIPng doesn't implement triggered updates, please don't use it for
>testing.)
>
>So we're speaking of 90 seconds worst case -- including the time needed
>for virtual link sensing --, and roughly 55 seconds average convergence
>times, with the default timers.  (Note that the biggest part of this
>figure is due to the slow virtual link sensing -- counting to infinity is
>not the main flaw of RIPng, contrary to common perception.)
>
>That's abysmally slow when compared with OSPF, but way less than the time
>needed for an ADSL modem to reboot and establish ADSL sync.  I'm not sure
>we should be promoting RIPng at this stage, Acee, but neither should we
>disqualify it outright.  If somebody comes out with strong arguments in
>favour of RIPng, we should be keeping an open mind.

I¹m fine as long as the consensus of the WG is that it meets the
requirements. 

Thanks,
Acee 



>
>-- Juliusz (who is looking forward to implementing the source-sensitive
>            extensions to RIPng)

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