I am some consultancy work for a charity organization. They currently share our data center where 2 citrix server are located. They have around 15 branch offices that connect to the data center via VPN tunnels. All branch offices use either Cisco 831 or 1801 routers. Each branch office has a 512 or 2MB ADSL connection.
Branch offices are reporting slow response for their citrix apps.
My recommendation would be that they move to private network and not use VPN tunnels and also upgrade ADSL links to SHDSL, however being a charity cost is very hard to justify.
Also I thought about implementing QoS over the VPN, but not sure how effective this would be.
Can anyone give me some advice thoughts\ based on the above?
Thanks in advance