IXFR Question: BIND 9.2.x

[blrmaani]

Hi All,
  I am using BIND version 9.2.x on HP-UX.

I am using one master and one slave in my topology and the slave gets
incremental
zone transfer from the Master when I update a zone on master using
nsupdate.

Question:

When Master initates a zone transfer using incremental zone transfer,
how long will
it take to complete the zone transfer?

Can I query slave and master for the serial number for the zone under
consideration
and if the serial number on slave matches with Master's serial can I
conclude that the
IXFR is complete?

In Master's syslog I noticed a message which says "incremental zone
transfer started.."
but didn't end of zone transfer message.

thanks in advance
regards
Blr