Troubleshooting Ping

Dac

I'm not sure if this is the best venue for this, as it's more like tech support than anything, but here goes.

Approximately three ago, my DSL service - which had been very steady for over a year - began to experience serious issues. For one day, the line was basically unusable - it dropped me every ten minutes, and was extremely laggy/unstable during those times it was up. In the days afterward, the line appeared to calm down, though still would disconnect around 5pm every evening, and when it came back up - which was almost instantaneous - its bandwidth was halved (700-800 kbps). I wouldn't be able to get my speed back to its normal cap (1536kbps) until the next morning, where running a Diagnostic on my router tools would cause it to drop the line, then reconnect at its faster speed. This happened like clockwork every day for two weeks.

The bizarre thing about this period was that, while I had the annoyance of the 5pm disconnect and slowdown, my ping on applications was -extremely- low. My ping on favored servers on TF2, for instance, went from 63 to 35. So, too, did League of Legends. My usual WoW server, which is located in the central timezone of the US, typically had a ping of 130-140 pre-problem, but went down to 60-80 during the problematic two weeks.

I had a tech come over and look at the line . There was nothing wrong with the router or our phone-line itself that was causing the drops at 5pm. He said he would move us to a different redback, and try some other things, but for two days after he finished his work, we continued to have issues...

And then the service stopped dropping me and cutting speed at 5pm. Rejoice! But, alas, my ping has jumped back up to its previous levels. Boo?

What would be the cause of something like this? Is there a reason why having a good sustained connection DOESN'T lead to that great ping? Is it a problem with routes and server hops? (I have 11 hops between me and yahoo.com according to tracert right now.) Is there anything I can do, or should I bother the tech again?

Being able to fix my ping back to those low levels would be great - I want to make sure I'm getting my money's worth on the line.

Currently using a 2wire router/modem combo.

Previous test as of 11/29, during the period where I'd have connection instability in the evenings (note the low ping):


Current test (Please note that San Francisco is MUCH closer to my address in Oakland than Palo Alto):

twmjr

I can't answer your question definitively, but one of the things you need to understand about pings is that their traffic type (ICMP) is generally extremely low priority in a network. For example, in a congested network, voice/video/general application traffic is generally going to be classed above ICMP traffic. The network will make sure those traffic types get through first, even if it means dropping some ICMP traffic.

It's one of the reasons ping tests are only somewhat useful in determining anything more than reachability. They may tell us something about latency/loss but not the whole story.

I would say, for all practical purposes, you won't notice much of a difference between a connection coming back as a 65ms ping and a 32ms ping. It looks like a lot bigger difference than it really is.

vonPoonBurGer

They probably fixed your stability issues by switching you from a Fast Path connection to an Interleaved connection. Fast Path is pretty much what the name implies, in terms of average latency it's measurably faster because it sends data in order with a minimum of forward error correction. Interleaved essentially shuffles the data you're sending down the wire and adds more redundancy. This causes average latency to be higher (because your DSL modem may hold data for up to 50ms as part of its shuffling), but it reduces the chance that line noise will drastically affect your connection. My guess is there's some marginal copper between you and the access concentrator, so unfortunately for your location you can have low latency, or a stable connection, but not both.

Dac

I'm relatively sure my connection was on interleaved, but looking around, it's looking more and more likely that it was on Fastpath.

The tech left me his card, so I guess I'll ring him up and get a ticket filed. Perhaps he can poke around and tell me whether I can go back to Fastpath without f*cking my connection again.

Preferable, since most 'statistics' in my diagnostics seem to be alright.

@twmjr - The problem isn't really with 30->60 ping games, that is pretty much nothin', but when I go from, say, 60 ping on a favored TF2 server to 110-120, that hurts a little more.