This is not specific to Diablo 2 but as we’ve all suffered with latency issues it’s interesting (to me at least) to see why this can be such a problem especially directly after the release of a patch.
On the release of the last two patches for World of Warcraft, Virgin Media ADSL customers have suffered terrible latency. Not just during patch download periods but long after as well. This problem may not just be due to a flakey provider, but the game developers themselves.
Usually gaming traffic is classified as high-priority (as is VOIP) and therefore gets the majority of bandwidth. Unfortunately, it appears when Blizzard patched WoW it caused Virgin, in these instances, to recognize “the type of packets used by Blizzard….has changed significantly.” and therefore treat them as peer-to-peer bumping it to the bottom of the pecking order and Lagcity. The blame, according to Mark Wilkin, Support Forum Manager at Virgin Media lies squarely with the developers and not the ISPs.
“We appreciate that some customers will have noticed a similar issue with the previous World of Warcraft update. The reason behind this is because gaming companies are not prepared to share the updates with Virgin Media or traffic management suppliers prior to its release and so the first time we see the new packets is when people start to use the new updates. We are trying to change this view point of the gaming companies however at present they are un-willing to work with us.”
I don’t know whether Blizzard’s patches have affected Virgin Media only but it’s the only ISP I’ve seen put out a public notice about it. Obviously game companies can’t send patches ahead of release but there could be a compromise whereby the relevant information that is likely to affect their ‘traffic shaping’ systems can be sent to major ISPs in advance sparing gamers the weeks of frustration trying to play a very lagged game.
Source: Think via WoW:IncGamers.