Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!sun-barr!newstop!sun!amdahl!netcom!jbreeden
From: jbreeden@netcom.COM (John Breeden)
Newsgroups: comp.dcom.lans
Subject: Re: 10Base-T hubs
Keywords: 10Base-T
Message-ID: <1991Apr13.195139.5149@netcom.COM>
Date: 13 Apr 91 19:51:39 GMT
References: <1593@vtserf.cc.vt.edu> <1991Apr11.044735.1221@ux1.cso.uiuc.edu> <721@synopsys.COM>
Organization: Netcom - Somewhere in the S.F. Bay Area
Lines: 42

In article <721@synopsys.COM> arnold@synopsys.com (Arnold de Leon) writes:
>
>	Another thing I like about 10 base-T is the ability to
>monitor link status.  Given the right hub you can tell if a host
>has been unplugged or powered down or up.  You can potentially use this as
>a way to monitor access to your network.  It would be more difficult
>for a user to add an unauthorized node.
>

I really don't think that LI  by itself provides or adds any real 
"management" capability to 10baseT.

1. What good is it to know if a station is either unplugged OR
   powered down (or dead)? I need to know which it is, LI by itself
   doesn't tell me.

2. In terms of an "unauthorized" node on the net, it seem that refurs
   to an "unauthorized" mac address. Just unplug a "known" node and
   plug in a new device. LI won't know the difference (and LI "dis-
   apearing" momentarily dosn't help - LI has no way of telling WHY
   LI went away (see #1).

3. LI can't tell me how GOOD a connection I have, just that SOME type
   of connection exists. Real World: Bad TP wire run drops 10-20% of
   the packets sent - LI reports "all ok".

LI IS a real handy function when INSTALLING wire/nodes (lets me know I have
tranceiver to transceiver connectivity), but is pretty usless as a way to 
"manage" my network. Knowing that I don't have continuity is pretty useless
until I know WHY.

I've seen one MAJOR company that decided to alarm EVERY LI port to EVERY PC
in their network. It lasted one day. At 5 o'clock their management system
went crazy - everybody turned off their PCs and went home.

-- 
 John Robert Breeden, 
    jbreeden@netcom.com, apple!netcom!jbreeden, ATTMAIL:!jbreeden
 -------------------------------------------------------------------
 "The nice thing about standards is that you have so many to choose 
  from. If you don't like any of them, you just wait for next year's 
  model."