[cisco-voip] Remote Site TFTP Woes

[Mike King]

We have a remote SRST site that we're bringing up.  We normally do a
P2P link with a ping RTT of 3ms, but this site got rushed, and the P2P
link is still on 120 to 180 day order.

We bring the site up using Comcast Cable modem service(50down 20 up).
RTT is around 30 ms.

We use ASA to ASA IPSEC L2L tunnels

When the phones register, the TFTP traffic for the firmware upgrade is
dog slow.  To the point where the phones eventually stop downloading
it.  (We packed all the phones up, and dragged them somewhere else to
upgrade the firmware, that's not the issue)

I fire a TFTP client up on my laptop, and a TFTP server at the same
site as the callmanager, and transfer a 90MB file.  It takes around 2
hours.  If I use windows file sharing, it takes about 4 minutes.

I have a TAC case open with ASA Security / VPN.  I'm getting chatter
that "tftp is a lock-step protocol that requires an ack to be sent and
received for every data packet sent, before the next packet is sent"
and with the RTT we have that is the maximum speed we should expect.

So for the next time I have to upgrade the firmware on the phones at
that site, what are your suggestions?

The way I'm seeing it:
1.  Something is Broke, and TFTP shouldn't take that long.
2.  Yes, that's normal, you will have to do something different, like
use a TFTP load server.

So which is it?  Any opinion is welcome.