Problems with Skype and the Cisco VPN Client

I have a variety of problems with Skype call quality, and calls being dropped, whilst connected to a Cisco VPN Concentrator using the Cisco VPN Client. I am using version 4.8.02.0010 of the client. I would be interested to hear from anyone else who has problems with this, and if you managed to find a solution, I’d love to hear about it.

Ideally, Skype is allowed Local LAN access, and goes out via that interface, whilst other VPN traffic moves normally across the VPN. I understand this might require split tunneling? Other people have told me that they don’t have these call problems, so I am wondering if it is a problem with my machine configuration.

I am using a vanilla Linksys WRT54GS router, connected to a cable modem (with no configuration access). I have setup port forwarding to direct Skype into a desired port, and without VPN, those calls are crystal clear. Are there any other settings on the router that might improve VPN and Skype quality?

Using the Cisco VPN Client’s “Stateful Firewall” definitely causes problems, but that doesn’t surprise me since Cisco bought in third party code to accomplish this task (Zone Alarm). What implications does switching this off actually have in terms of a security risk?

So, what are the options? What is the best configuration? How can you fix the client without degrading security on the VPN (split tunneling is not recommended)? I welcome any comments.

UPDATE

I have upgraded my Cisco VPN Client from 4.8 to 5.0.04. Although the problem still happens occasionally, it is much less frequent than it was. I hope this helps others with the same issue.