CS.S Latency Issue!

We r having big latency issue in counter strike source here in Peshawar. some how the latency is around 350+ when a player from different isp connects. our server is mostly on Ptcl which runs okay for Ptcl players as they get around 30-40 latency but when a player connects from Link.net it shoots to 350+, same is the case if server is made on Link connection then Ptcl players have high latency. this wasn't the case last year when we played CS 1.6 on same connections. the problem now occurs even in CS 1.6 too so i am sure its not from the game itself.

Have any of guys experienced the same situation and do u know y its happening ?

Yeah Pings are very high now.. Don't know for what reason..I used to get 20-25 ping on Linidtonet and now its like 220-250 lol