Real-Time displays are not always updating when connected via VPN

[MrPederman]

Real-Time displays are not always updating when connected via VPN. Sometimes they work correctly for two hours and then they will just stop updating. We have verified that all the ports are open on the firewall and we are not seeing any packet-loss, so what else could stop them from updating?

We are SCCS 5.0 SU06 and SWC 4.5 SU07. Client PC's are XP.

Also these same client PC's work OK while they are in the office.

It would be easy to say it is the customers network, and I would agree, but I have to help them figure it out.

Any Ideas?

Thanks in advance.

 

[captaingadget]

When these RTD's are working, are they using muticast or unicast? This can be identified by a M or U next to the LAN symbol at the top of the display. If unicast you may be reaching the unicast limit. The most likely explanation is delay in the VPN which will sort of drop the session. When the display next stops, run some ping tests to see what the round trip delay is.

 

[MrPederman]

Thanks for the response.

We are using multicast only.

We did some testing with a VPN user and a person on the LAN. We had the same RTD's open and we were running a Ethereal sniffer capture on each PC and discovererd that the LAN user was seeing UDP packets on all 12 RTD ports that Nortel NTP's say need to be open and the VPN user was seeing only 5 or 6 random UDP ports in use. It seems that some of the port traffic is being delayed or dropped. They have verified that the ports are open in the firewall, so the cable company my be at fault, be we are still investigating.