Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!cs.utexas.edu!sm.unisys.com!csun!lkw
From: lkw@csun.edu (Larry Wake)
Newsgroups: comp.dcom.lans
Subject: cisco-to-cisco over 1.5M serial?
Keywords: T1, cisco, CSU/DSU, is this trip really necessary?
Message-ID: <1751@csun.edu>
Date: 7 Dec 88 20:48:47 GMT
Reply-To: lkw@csun.edu (Larry Wake)
Organization: California State University, Northridge
Lines: 29

We have pretty much settled on using a high-speed serial connection to
bridge Ethernet segments located in two buildings on campus.  Our
proposed method is to use a cisco gateway server on each end, with what
they call their "T1" interface (for reasons that may become clearer, I
would like to avoid the term T1, though).  The cable between the two
buildings is T1-quality twisted pair (22 gauge dual D-screen), owned by
the university, not the phone company; the run is about 2800'.  Each
cisco board has a V.35 connector, and they will talk HDLC.

After talking with many, many vendors, we are still confused as to what
we need to drive the serial line.  Some (including cisco) say we need a
CSU/DSU, others say only the DSU portion is necessary, and still others
say only the CSU.  Prices range from $1500 to $5000 a side.

So, we still need to know what the technological difference between
the different types of equipment is to justify the wide price range.  In
a nutshell, our main concern is: what is the most cost effective way to
get a high speed (T1 or T1-C rate) connect between the two cisco boxes?
If anyone has any direct experience and/or product recommendations, we
would love to hear from them.  More general questions include: what is a
CSU?  What is a DSU?  Which of these is required only for telco
connects, and which can be eliminated in a private setup such as ours?

Thanks in advance,
-- 
Larry Wake                   		 lkw@csun.edu
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