d_l
Barsoom
Premium,MVM
join:2002-12-08
Reno, NV
| reply to larek
Re: [DSL] Modem Poisoning
Those are 5100b modems right? Because the 5100a modems won't make the connection.
I thought the maximum number of connections one of those modems could handle was higher, say maybe in the 40-60 range, but this is from memory so maybe wrong. I do know that if they aren't making the PPPoE connection then their connection "limit" is raised because the modem memory devoted to PPPoE is used for sessions instead.
One reason those modems are so connection limited is that their software is using some (a lot?) of the internal memory for ACK prioritization. Other modem models such as the notorious 2210 modems or the 2wires or older bridged modems don't prioritize ACKs and so you can have many connections open, but your download is choked to upload speed levels when doing intensive uploading.
Last year some experiments were were carried out to flash the AT&T version 4100 with generic 4100 software (actually it was an Australian ISP version of generic software). The connection limit was raised to the thousands before the modem would crash. ACK prioritization was eliminated though. |
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larek
join:2004-03-25
Hancock, MI
| 5100(b/a)? not absolutely sure, I'll check at lunch
The connection in the 40-60 range I don't know. 60-80 do die but it its sort of random. 200+ is guaranteed a quick death thats why I mentioned it. 24 is fairly stable.
I haven't done any testing with ACK prioritization on/off since I thought that PPPoE was the major resource consumer. I will start now test it too.
If the speedstreems are connection limited from ACK prioritization (and the limited resources that it consumes) Do ADSL modem cards (PCI?) have better performance since they can use the full system resources? Can the use the full pc system resources?
So if I offload the PPPoE and ACK prioritization, off the modem to a third box "PPPoE Server", and have the Modem in bridge mode, my problem might just go away? |
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larek
join:2004-03-25
Hancock, MI
2 edits | Nope I checked again they say just "5100", no A or B seen on the back.
What is meant by the term Generic Firmware? I assuming you don't mean the original factory Firmware. I read many posts that mention it in passing. Do you really mean 3rd Party Firmware, or non-provider branded firmware.
I'm wondering if ACK p could be turned off via the CLI command?
•Note: I'm asking about Firmware, not for Firmware
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wayjac
Premium,MVM
join:2001-12-22
Indy
 ·AT&T Midwest
| said by larek  :Nope I checked again they say just "5100", no A or B seen on the back. There are pictures of the 5100a, 5100b, 4100 and 4100b in this faq
AT&T HSI / Ameritech Modem Museum
said by larek :What is meant by the term Generic Firmware? The speedstream 4100 and 4200 router gui are almost identical
Below is a image of the speedstream 4200 router gui
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larek
join:2004-03-25
Hancock, MI | Ok so mine are the the 5 LED "b" version. They are from 04' |
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wayjac
Premium,MVM
join:2001-12-22
Indy
·AT&T Midwest
| reply to larek
said by larek :So if I offload the PPPoE and ACK prioritization, off the modem to a third box "PPPoE Server", and have the Modem in bridge mode, my problem might just go away? I think the problem is the nat table size more than ACK prioritization, can the load balancer be configured to do the PPPoE
The load balancer's nat table may be able to handle the many connections |
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d_l
Barsoom
Premium,MVM
join:2002-12-08
Reno, NV | Yes, normally these modems simply crash or reboot or drop sync when they have too many connections. |
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