johnl@ima.UUCP (02/02/87)
In article <272@gaia.UUCP> zhahai@gaia.UUCP (Zhahai Stewart) writes: >I gather that MNP is Microcom Networking Protocol, and is a error >correcting protocol or set of protocols, and is generally available >in modems if anywhere (ie: in a few modems, but not usually in >terminal or host software). Could someone tell us a little more >about it? Is it proprietary, and how much so ($) if yes? Is it >implemented at the async character level or at the internal synchronous >level in 212/v.22/bis type modems, etc? Is it forward error correcting >or automatic retry request? How much overhead is there? What is the >packet size, and how does it decide to send a short packet (if >it is packet oriented... I am guessing obviously). Where can >documentation be found and at what cost? Also, how well does it work >(anybody using it?)? I have a Microcom PC modem which implements MNP with a mixture of hardware and software. MNP is actually a family of protocols including a reliable conversational protocol, a simple FTP protocol, and a data-compressed FTP protocol. Some parts of MNP are pretty slick, for example when you go into reliable mode, the two modems shake hands and then switch from async to synchronous transmission. The 20% of the bits that this saves easily makes up for the protocol overhead. There is an interactive protocol which appears to send a packet every time there are any characters to send, with a little smartness to send bigger packets when the data are coming constantly. There is a file transfer protocol which seems to be like uucp's with a sliding window and retries. There is some provision for file format trans- lation which I have never used. Microcom used to try to make money from MNP but now seems to give it away for a handling charge, except for the most recent spiffy data compression FTP protocols which are still proprietary. Anybody who cares can call them up in Norwood MA at 800-322-3722 or 617-762-9310 and they'll be happy to send you all sorts of info on MNP. -- John R. Levine, Javelin Software Corp., Cambridge MA +1 617 494 1400 { ihnp4 | decvax | cbosgd | harvard | yale }!ima!johnl, Levine@YALE.something Where is Richard Nixon now that we need him?
zhahai@gaia.UUCP (02/02/87)
I gather that MNP is Microcom Networking Protocol, and is a error
correcting protocol or set of protocols, and is generally available
in modems if anywhere (ie: in a few modems, but not usually in
terminal or host software). Could someone tell us a little more
about it? Is it proprietary, and how much so ($) if yes? Is it
implemented at the async character level or at the internal synchronous
level in 212/v.22/bis type modems, etc? Is it forward error correcting
or automatic retry request? How much overhead is there? What is the
packet size, and how does it decide to send a short packet (if
it is packet oriented... I am guessing obviously). Where can
documentation be found and at what cost? Also, how well does it work
(anybody using it?)?
I suspect there would be sufficient interest to justify posting good
info to the net; if I am wrong, such as if this has already been covered
in detail before I started listening to this group, please let me know. ~z~
--
Zhahai Stewart
{hao | nbires}!gaia!zhahai