jparnas@larouch.UUCP (Jacob Parnas) (07/03/89)
I recently got SLIP going (4.3BSD), and while pleased with its function, I still long for better performance even with V.32 modems. The obvious thing to do is add compression. I knnow there should be a version of SLIP with header compression coming soon, but I am wondering if anybody has thought about compressing the contents of the packets as well as the headers. Has anyone out there implemented or thought about implemeting this? If you have, I'd appreciate it if you would drop me a note. Also, does anybody know if a modem doing MNP level 9 compression in hardware would help? (such as the Microcom QX/V.32c) Also, if one were add compression to SLIP, where should it be added? Would it be best to add it to if_sl.c? Thanks for any thoughts. ------------------------------------------------------------------------------ | Jacob M. Parnas | DISCLAIMER: The above message is from | | IBM Thomas J. Watson Research Ctr. | me and is not from my employer. IBM | | Arpanet: jparnas@ibm.com | might completely disagree with me. | | Bitnet: jparnas@yktvmx.bitnet \---------------------------------------| | Home: ..!uunet!bywater!acheron!larouch!jparnas | Phone: (914) 945-1635 | ------------------------------------------------------------------------------
smb@ulysses.homer.nj.att.com (Steven M. Bellovin) (07/09/89)
In article <5108@oregon.uoregon.edu>, jqj@oregon.uoregon.edu (JQ Johnson) writes: > One possible place to put compression is in the modem itself. The problem with putting compression in the modem is that you're still limited by the 9.6Kbps or 19.2Kbps pipe from the CPU to the modem. (Assuming an external modem, of course.)
jfh@rpp386.Dallas.TX.US (John F. Haugh II) (07/12/89)
In article <11771@ulysses.homer.nj.att.com> smb@ulysses.homer.nj.att.com (Steven M. Bellovin) writes: >The problem with putting compression in the modem is that you're >still limited by the 9.6Kbps or 19.2Kbps pipe from the CPU to the >modem. (Assuming an external modem, of course.) Putting compression in the modem will make it more tolerant [ depending on modem technology that is ... ] of noisy operating environments. Consider a data stream being compressed 50 percent. As the quality of the link degrades, the utilization may increase from 50 percent, which it was limited to by the baud rate at the modem interface. The utilization rate is able to increase until the modem is once again operating at the interface speed, or the the [ very ] noisy line limits the data rate at the interface. At some point in time it would be nice if a hardware vendor would create a bidirectional parallel interface and put a modem on it. That company would probably earn quite a few dollar$ doing $o. -- John F. Haugh II +-Quote of the month club: ------------ VoiceNet: (512) 832-8832 Data: -8835 | "Computer security is to information InterNet: jfh@rpp386.cactus.org | control as a chastity belt is to UucpNet : <backbone>!bigtex!rpp386!jfh +- birth control" -- Doug Steves --