Dialup ISP Connect Speed

[PoeBoy]

What factors determine your dialup connection speed with your ISP, both hardware and software related?

 

[yomega]

Granted I don't know much about TCP, but I'll still put in my $.02

First, the most obvious is the speed of the modem.
I don't believe that software affect the actual connection speed (bps) but software can make the connection more effecient. What determines the speed the most is the FCC and noise on the line. The FCC limits the connection speed to about 53Kbps, due to cross-talk at anything higher. If the wiring in your house/city is old the noise will hurt your connection. Where I live the line conditions limit my 56K modem to 26.4K.

Hope this helps.

 

[PoeBoy]

Appreciate your input - my line is relatively new, up until a few weeks ago I consistently connected at 43,000 to 49,000 bps, then my average connect speed dropped to low 20's. My suspicion is that my ISP has decided to limit bandwidth to an individual dialup client in order to reduce associated costs. Any validity to this theory?

 

[CStroman]

Yeah, your ISP could've done that. The ISP is another speed-altering factor. If you have a busy ISP like AOL, you're gonna get connections slower than molasses on a cold day.

 

[LuNoTiCK]

Maybe it's time to change ISP's.

 

[skyking]

A negotiation occurs when you first dial up a modem in the modem pool for your ISP(for lack of a better explanation). The two modems establish the highest connection speed possible without errors. Reductions in speed on a strictly modem to modem basis are caused by incompatabilities between the modems, and signal quality issues.
Signal quality can be affected by poor connections in the copper between your modem and the phone company's switch, and the distance between your modem and the switch.
If you are connected via underground copper and pedestals, moisture in the connections can ruin your signal quality.
All that aside, your ISP may be reducing the bandwidth also.
Hope this helps. The phone company switch me to another pair of wires to correct a static problem, and I saw a remarkable improvement in modem speed and voice quality.

 

[EppyThatcher]

like skyking said, the major factor is the middle man between your machien and the isp, the phone line that connects you to the phone company and the phone chord that connects from your wall to your computer, sometimes splitters or old phone chords cause slow downs.

 

[ProviaFan]

I get a 52,000bps connection reliably with the local ISP (Joink in the southern Indiana area, FYI). However, it is unfortunately a rara avis that I get a 53,333bps connection

 

[cyclones]

In the UK the telephone lines are optimized for VOICE telecoms.
If your interest is more digitally angled, you can have the line gain increased to optimize
fax, modem etc.
Our default is 0 ..zero and the peak is 5.
The trade off is at setting 5 you can sound a little bit echoeeeeee, but only sometimes.
If this is not an available option in the USA or maybe various telcoms please advise.
Gung Ho!

 

[Nefrodite]

what pisses me off is my neihbor got dsl.. they installed a buffer thing at the central office or something and now he can also dial up with 56k connections. i'm still stuck with 28.8 and calling pacbell was useless since they had no idea what a buffer was

 

[lowlevel]

Just want to re-affirm that phone lines are usually the culprit.

Unfortunately, the "newness" of the phone line itself has little to do with issues like this, since it's very difficult to tell whether (if it's a phone line issue) it's happening:

a) inside the house

b) in the line running from the pedestal to your house

c) in the pedestal itself

d) or somewhere a mile down the road

It can be a pain in the arse to troubleshoot this sort of thing, but if you know someone else that gets higher-speed dial-up connnections, try taking your rig over to their place and dialing out. See if your speed goes up.

While this isn't a comppletely accurate gauge, as I've seen different modem chipsets react a little differently running off of the same wall jack, this can at least give you an idea of whats going on.

 

[Shalmanese]

Hey, I just noticed that My connection has been dropped to 37333. Usually it runs at 115200 which does absolutely nothing except as a prestige thing since I only have a 33.6K anyway. Lines been getting flakey today, had to dial in 3 times to get a connection, 2 different error messages each time it failed.

 

[Fritzo]

I'm a systems engineer for a large national ISP, so here's the low-down:

1) Your ISP DOES NOT have anything to do with your connection rates. 99.99% of all dialup ISP's now use 56K modem pools, and that equipment is designed to connect with an incoming modem at it's highest RELIABLE speed. There isn't some geek behind a router going "You know...I'm going to limit everyone to 36000 today."

2) The biggest determining factor in your connection speed is signal quality and modem compatibility. The more trunks your call has to pass through and the greater your distance from your closest telco central office, the lower your speed will be. People in apartment complexes and sub-divisions are often victim to "line sharing", where they don't have enough wires on the poles to give everyone in the neighborhood a separate line, so they run multiple signals over a single phone line. This will kill your connection speed at various times of the day and cause disconnections if you have a lower quality modem. You're speed will most likely be 26-33K if this is the case. Speaking of cheap modems, modems made with the PC-Tel and HSF chipset are notoriously problematic. They like to dial into Lucent and Siemens equipment, but have a lot of problems with Cisco, Acsend, and many other modem pools. You should replace these types of modems if you're having disconnect/connection speed problems.

3) Don't confuse throughput and connection speed. Your modem will try to connect at the highest rate it can, so if you're getting a 36000 connect, then that's the highest speed that the current phone line conditions will support....that has no bearing on the ISP. Now, if you're connecting at 48000 and your THROUGHPUT is only 28000 consistantly, your modem may be negotiating at too high of a rate (in otherwords, it's being overly optimistic about the line quality...USR modems are famous for this). Try limiting your speed with init strings, or adjust the modem's port speed to 57600 or 38400. (Note you must adjust the port speed from your dialup networking connection for it to take effect).

4) Your ISP's capacity will not have any bearing on your connection speed, but it might effect your throughput. However, to saturate a single T1 with normal 56K traffic, you'd need about 200 simultanious connections, and most ISP's have at least 2 T1's. Capacity problems normally result in busy signals, not throughput problems.

I hope this clears things up a bit. BTW- not to self promote, but we have a great performance test located here: Performance Test

You can chose a test that's closest to you and measure your ISP's throughput, then it compares your results to the average of the other test takers. It gets about 100,000 hits a day, so it gives a pretty broad range on connection speeds from 33.6 to ISDN to T1.