I found a previous post here
http://www.geekzone.co.nz/forums.asp?ForumId=49&TopicId=13689
However, it seems to have been locked. Basically I am having the exact same issues recently with very bad ingame latency [as high as 1600ms] during the evenings, my normal expected latency historically has been 300-700ms to my server [Uther]. I have run numerous speedtests that Xtra suggest and the line speed seems ok. I have done a lot of tracerts, often indicating dropped packets after the jetstream.co.nz hop. To this date xtra will not take responsibility for this.
A guildie on the same server, based in the same city, has had no such issues and he is using Telstra Clear. I've updated my NIC drivers and the router seems ok. I could switch to Telstra but a) if it's a local infrastructure issue how will that help and b) I would also have to change to them for the phone line/calls.
This is seriously ticking me off.

Edit: Rush typed this during an off-moment at work. I don't have my most recent tracerts on hand here but here is one example;

Tracing route to us.logon.worldofwarcraft.com [12.129.224.112]
over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms mygateway1.ar7 [10.1.1.1]

2 48 ms 50 ms 51 ms 222-152-0-1.jetstream.xtra.co.nz [222.152.0.1]

3 * * * Request timed out. [Should be MDR-IP03e-2-1-0.akbr3.global-gateway.net.nz]

4 325 ms 203 ms 201 ms 202.50.232.205

5 199 ms 200 ms 208 ms so1-2-0.tkbr9.global-gateway.net.nz [203.96.120.74]

6 359 ms 364 ms 344 ms so1-1-3.labr5.global-gateway.net.nz [202.50.232.18]

7 385 ms 386 ms 378 ms ge-3-0-0.labr4.global-gateway.net.nz [202.50.232.178]

8 364 ms mygateway1.ar7 [10.1.1.1] reports: Destination protocol unreachable.


Trace complete.

I do have ZoneAlarm running, however, WoW has been set to a trusted app. I did disable ZA but there didn't seem to be any difference. The server I'm on has a fairly high population but noone else I know in the guild [that are Kiwis] has had the issues I'm having currently.