Re: [dhcwg] Review of draft-ietf-dhc-dhcpv6-failover-protocol-00

[Simon Hobson <[e-mail]>]

Kim Kinnear <[e-mail]> wrote:

> Folks,
> 
> One of Bernie's comments on the failover draft was:
> 
>> -          7.1 (Time Skew) – Should we require NTP to synchronize the clocks on failover partners?
> 
> The current draft (-00.txt) has a capability to allow the failover
> protocol to operate with two machines which have clock skew of a
> largely arbitrary amount (limited in some way to perhaps 24 hours or
> something).  So two systems that are 3-5 minutes apart (the usual
> skew, if any) will work fine.
> 
> Bernie is suggesting that we require failover partners to have
> essentially synchronized time by requiring NTP sync.  If they are
> synchronized to the level of 1-2 seconds, that would be synchronized
> for the purposes of this protocol.  We aren't talking milliseconds
> here.

I see two points :

1) If the time should be synced, then I would suggest merely requiring that, rather than specifying NTP - ie specify the what rather than the how.

2) Are there any other benefits to having time synced ? Eg, does having a significant time offset make troubleshooting any harder - eg by having logs on two servers with different timestamps for the same event ?
I'm inclined to thinking that there's isn't really any argument against having server times set correctly, particularly for services (such as DHCP) which include a time element. Perhaps if it's not an actual requirement, it should be suggested as recommended practice for stability and ease of troubleshooting - or is that going too far into "stuff any half decent admin shouldn't need telling" territory ?