Experienced lags

Hi! :) I'm new here.

All of my dungeon group members recieved lags (ping) up to 3 secs delay for recent 15 mins. As a result full wipe 2 times and 20 mins of wasted time. Dungeon run ruined.
Server: Icecrown

Is that to be considered frequent? How should I respond and react to it? Is there a certain time when it's ocurring more often?

Thanks in advance.

I've been unable to log in for more than 45 mins now and at first started with lags, than i got a lag for almost 5 mins without disconnect. I closed the game manually and after that I've been unable to connect. Icecrown has it's own lags and everything but the last 3 days it's been hell. Honestly I don't even wanna play anymore.