On 24/04/07, Nguyen Huy Ha wrote:
> > Hi, Is it possible to get timestamps of responses right when they leave
> > their agent, and how?

You could turn on packet dumps, which by default would get logged in
the agent's syslog - complete with timestamp.

> It should be impossible since there is no timestamp field in SNMP/UDP/IP
> stack.

It's certainly true that timestamps are not part of the SNMP protocol.
This is deliberate - since SNMP may well be implemented on fairly
low-level hardware, where they may not be any form of externally
reliable timestamp.
That's why the fundamental time measurement for most MIBs is
'sysUpTime' - the length of time that the agent has been up and running.
This is purely self-contained, and doesn't rely on any external clock.

> I was just wondering that the counter values that we get from agents
> would be more precise if we have also the timestamp at the agents since it
> also takes a while for responses from agents to get to their manager.

Quite honestly, I suspect that delays in retrieving the counter values
from the underlying subsystems would be of equal significance to
network delays. Even more so when it comes to any internal caching
of data within the agent.
All that a timestamp would give you would be the time that a response
was sent - which is not necessarily the time that the individual counters
were actually sampled.


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