From: Daniel Ramirez (daniel.ramirezdelamo@gmail.com)
Date: Tue Jun 13 2006 - 07:01:59 ART
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 <rofernandez@us.telefonica.com> 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 <BB1 ip address> preferred
> ntp peer <R6 ip address>
>
> R6
> ntp server <BB2 ip address> preferred
>
> Configuration for #2
> --------------------
>
> R3
> ntp server <BB1 ip address> preferred
> ntp server <R6 ip address>
>
> R6
> ntp server <BB2 ip address> preferred
> ntp server <R3 ip address>
>
> 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
>
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