North American Network Operators Group

Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical

Re: Question on Loosely Synchronized Router Clocks

  • From: Xin Liu
  • Date: Tue Sep 18 11:58:03 2007
  • Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; bh=g2H0vpte8P0wORYZWlXvzZygktDQ4Dj9xBCTgF1OiKA=; b=Ke3SPwD06OKKjk9ytCbq6aMR8ffXUvARLPoXCwR9rKpAh3k+sP44lq4ZJZiO1HmnoHq1QYYQ/rW0rKMggKqAfBJ+OSohw4ctH44O4eAGGUm7KCsektP10HHjovKMMlchM/tXAsqB/U7OWlH6qqlVUXC7Z913LWQucqSObEoAqZ8=
  • Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=Gb3YBiRkHbfKo4run9lGxq8Sd2WcfMKYAkhgD1lvXcsHu7cDssBkyMGuU/Xubs2QeHeck+GPEtDOK1YMCpjDtqqYBN/S6IXL2yyK8T2I89WP0IQdYZbsGmZTBcBVgdr6p5T/CYSSoS3aMmOykFx+iMy1Nck0lOTUqNQHCyiT3NQ=

Ideally, yes, a protocol should not rely on clock synchronization at
all. However, to ensure freshness of messages, we don't have many
choices, and clock synchronization seems to be the least painful one.
So we asked about router clocks on the current Internet. If normally
router clocks are synchronized and we have a mechanism to detect and
fix out-of-sync clocks, is it reasonable to assume clock
synchronization in the rest of our design?

Best
Regards,

Xin Liu

On 9/17/07, Bora Akyol <[email protected]> wrote:
> IMHO:
>
> What ever solution you end up proposing should able to handle (3) and should
> work with arbitrary boundaries for (1) & (2).
>
> We don't want to add another failure mode to the network that depends on
> time synchronization.
>
> You don't want to shift the problem from BGP to NTP.
>
> Regards
>
> Bora