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Daniel,
Thank you very much; it makes total sense when seen that way.
It looks to me more philosophical than technical because a stratum level more or less, doesn’t make the difference. But from the hierarchical design point of view, it is the answer. Being this the line followed by every lab I’ve seen, it is the law from now on.
Thanks again, Roberto

—–Original Message—– From: Daniel Ramirez [mailto:daniel.ramirezdelamo@gmail.com] Sent: Tuesday, June 13, 2006 6:02 AM To: Roberto Fernandez Cc: Cisco certification Subject: Re: NTP associacions, help on hidden semantic details
Roberto,
The key point is the stratum level. The stratum architecture defines the ntp relationship: + You must configure “ntp server” when you want to synchronize with a more reliable time source (i.e. less stratum level). Ntp server => In this case you request time info to a reliable source + You should use “ntp peer” when you want to interact with a time source of your same stratum level (i.e. same reliability). Ntp peer => In this case you request time info & you provide time info to a time source of the same reliability.
In your example: BB1 & BB3 are more reliable time source => configure server relation. R6 & R3 (same level of reliability) => configure peer relation.
Best Regards.
D. Ramirez Network Engineer Telefonica Data

On 6/12/06, Roberto Fernandez wrote: > Friends, > > I need your help trying to figure out, where are the key works which led > into one direction or the other. > > > The requirements of IEWB Vol 1, Lab 1, Session 9.3 are as follows: > > -Configure R3 and R6 to get network time from BB3 and BB1 respectively > -Configure R1, R2 and SW1 to get network time from R3 > -Configure R4, R5, and SW2 to get network time from R6 > -R3 should fail over and get network time from R6 in the event that BB3 > becomes unavailable > -R6 should fail over and get network time from R3 in the event that BB1 > becomes unavailable > > > Here I see two solutions to fulfill the last two requirements, > > 1- The “ntp peer” > 2- The “ntp server” (taking the precaution of adding the preferred > keyword to the server commands pointing to BB1 and BB3 > > Configuration for #1 > ——————– > R3 > ntp server preferred > ntp peer > > R6 > ntp server preferred > > Configuration for #2 > ——————– > > R3 > ntp server preferred > ntp server > > R6 > ntp server preferred > ntp server > > The answer key prefers #1 and it also the choice for some other similar > questions. Maybe I’m lost on the semantics of the requirement so I’d > appreciate if someone can point to the keywords which lead to the right > solution. > > Thanks again > >