As far my understanding there could be many reasons for the slowness over IPsec VPN.
Your internet traffic might be on peak
Remote network traffic might be on it's peak.
Remote local network may have slowness problems due to many reasons ( Intermediate devices , broadcast flooding etc)[/ul]
And if you are using an interface based VPN create a seperate policy only with the Telnet service with " Traffic Shaping " options. And put the normal access policies below on that. So atleast you can ensure your telnet traffic is not stuck on traffic queue and it will have priority.
But Still I don't think that it will help you to fix the slowness issue unless you find out the root cause for the slowness issue. :)
I have to agree with nihas, and would even add have you ran any L4 analysis between client and AS400? A opensource tool like tcptrace will provide details on tx/rc retrans, delay,etc.....
Once you have any ideal of the traffic statistics, than you can drill in. Also keep in mind you mem=ntion prioritizing telnet over ipsec but how much ipsec do you have at either vrs the available bandwdidth?
I would start by graphing the ipsec tunnels ( hopefully they are ALL interface mode ) and try to look at the available bandwidth and utilization at each ends.
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