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Q97977: RAS and Telebit PEP

Article: Q97977
Product(s): Microsoft LAN Manager
Version(s): 
Operating System(s): 
Keyword(s): 
Last Modified: 30-JUL-2001

SUMMARY
=======

It is recommended that you do not use Telebit's proprietary PEP compression
method with Microsoft Remote Access Service (RAS). It will actually slow down
data throughput rates with RAS.

MORE INFORMATION
================

PEP is a method implemented in some Telebit modems to get higher data throughput
over slower DCE rate. Using a normal terminal for file transfer over a 9600 bps
PEP connection, you may actually get DTE throughput closer to 19,200 bps. RAS is
more of an interactive application that both sends and receives smaller packets
of data. A PEP connection with RAS is actually much slower than a non-PEP
connection at the same DCE bps. The reason is that PEP holds back small packets
of data to compress them when more packets of data come from the system. This
has the effect of holding back NBFs\AsyBEUIs acknowledgment frames. Hence,
frames are resent, timeouts occur, and in general things slow down. A straight
9600 bps connection without PEP is actually faster for RAS.

Additional query words: 2.20 v.42bis mnp 5 1.1 1.0 3.1 error correction data compression.

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