[ntpwg] [dhcwg] NTP option: IP address and/or FQDN

[Danny Mayer]

Hemant Singh (shemant) wrote:
> Folks,
> 
> Sorry for the delayed reply. I also have not been following this thread
> at all. I have just heard in the IETF meeting about using FQDN vs. IP
> address discussion or using both.
> 
> I would like to point folks to the MGCP VoIP protocol in RFC 3435 where
> they also had to decide between FQDN and IP address. See section 2.1.4
> of this RFC where Call Agent is the server that serves MGCP clients to
> talk with the Call Agent. 
> 
> My 2 cents.
> 
> Hemant 

This section of RFC 3435 is interesting though not really an exact
parallel. That section basically wants you to use FQDN and use all of
the addresses if one fails. That part is what we want to do especially
with the pool. It also, interestingly, wants it to keep track of the TTL
of the records. Unfortunately getaddrinfo() and friends don't return
that information, so it's hard to see how that part could be implemented
without going to a raw DNS protocol. This gets really interesting with
NTP which may jump the time by any amount at least initially, so you
don't know what the TTL left is.

MGCP also operates in a totally different manner since VOIP, although it
can daisy-chain through a number of proxies is limited to the number of
systems likely to be involved. NTP on the other hand expects every node
in a network to be using NTP.

Danny