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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 > > _______________________________________________________________________ > Subscription information may be found at: > http://www.groupstudy.com/list/CCIELab.html