(usr-tc) V.42 selective reject
I've just loaded the Hi-Per DSP firmware version 2.0.51 into one of our TCS hubs for testing. In older versions of the firmware (I think 3 or so versions prior to this one), the default setting for V.42 Selective Reject was disabled. However, newer versions of the firmware including this most recent one have it enabled by default. The docs indicate it benefits modems and phone lines experiencing some packet loss. However, up till now, we disabled V.42 Selective Reject explicitly just to ensure the same behaviour on our TCS with previous versions of the firmware. We even disabled it on the quad-modem cards for the same reason. This time we're leaving the default setting alone (enabled) but I'm wondering if this might be opening us up to increased problems with customers running older modems. I haven't yet noticed any mention of this feature on the lists or in the archives so I thought I'd ask directly. Has anyone run into problems with using V.42 Selective Reject on the quad-modem cards (version 6.1.6) and/or the HiPer DSP modem cards (version 2.0.81 or 2.0.51)? If so, what percentage of users were affected? What kinds of modems were most susceptible to problems, if any at all? Antonio Querubin - To unsubscribe to usr-tc, send an email to "majordomo@xmission.com" with "unsubscribe usr-tc" in the body of the message. For information on digests or retrieving files and old messages send "help" to the same address. Do not use quotes in your message.
As far as I know, Selective Reject is only supported by 3Com client modems (err, USRobotics, or whatever little company it is that owns that product now, sigh)... but anyway it seems to be safe in every config combo we have here (Quad, DSP 2.0.51, all client modems). Short version of what it does is that it reduces the amount of data that's retransmitted when a v.42 frame gets corrupted. It's an optional part of the v.42 spec and not many people bothered to implement it. For client modems that don't implement it, it doesn't make a bit of difference whether you turn it on or off at the server end. Mike Andrews (MA12) * mandrews@dcr.net * http://www.bit0.com/ VP, sysadmin, & network guy, Digital Crescent Inc, Frankfort KY Internet services for Frankfort, Lawrenceburg, Owenton, Shelbyville www.fark.com: If it's not news, it's Fark. (Or something like that.) On Sat, 25 Mar 2000, Antonio Querubin wrote:
I've just loaded the Hi-Per DSP firmware version 2.0.51 into one of our TCS hubs for testing. In older versions of the firmware (I think 3 or so versions prior to this one), the default setting for V.42 Selective Reject was disabled. However, newer versions of the firmware including this most recent one have it enabled by default. The docs indicate it benefits modems and phone lines experiencing some packet loss.
However, up till now, we disabled V.42 Selective Reject explicitly just to ensure the same behaviour on our TCS with previous versions of the firmware. We even disabled it on the quad-modem cards for the same reason. This time we're leaving the default setting alone (enabled) but I'm wondering if this might be opening us up to increased problems with customers running older modems.
I haven't yet noticed any mention of this feature on the lists or in the archives so I thought I'd ask directly. Has anyone run into problems with using V.42 Selective Reject on the quad-modem cards (version 6.1.6) and/or the HiPer DSP modem cards (version 2.0.81 or 2.0.51)? If so, what percentage of users were affected? What kinds of modems were most susceptible to problems, if any at all?
Antonio Querubin
- To unsubscribe to usr-tc, send an email to "majordomo@xmission.com" with "unsubscribe usr-tc" in the body of the message. For information on digests or retrieving files and old messages send "help" to the same address. Do not use quotes in your message.
- To unsubscribe to usr-tc, send an email to "majordomo@xmission.com" with "unsubscribe usr-tc" in the body of the message. For information on digests or retrieving files and old messages send "help" to the same address. Do not use quotes in your message.
participants (2)
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Antonio Querubin -
Mike Andrews