SUMMARY: Ethernet Bridge

From: Lenny Simon (
Date: Tue Feb 02 1993 - 01:17:50 CST

Thanks to all for your response. Answers differ widely from
those who wanted to explain what a bridge is used for to those
with more constructive recommendations.
I appreciate all (even the sarcastic ones).
Date: Mon, 1 Feb 1993 08:51:11 -0500
From: Christian Lawrence <>
Message-Id: <>
Subject: Re: Ethernet Bridge
Status: RO

first of all, if you're segments are behind routers and you don't know what
you're doing you SHOULD NOT be farting around.

in any case, it seems like what you're seeing is related to bridge throughput.
a bridge buffers an entire incoming packet first, then checks for errors
(e.g. crc), then looks at the destination address and uses that to look up in
its interface/arp table to find out if it should dump the packet (destination
local to originating segment) *OR* forward the packet to a differnet interface.
All of this takes time and different bridges have differenet forwarding rates
and buffer sizes.

bridges should ONLY be used to logically group systems/stations together
in order to circumvent traffic problems from other groups.

From: Mike Raffety <>
X-Organization: Swiss Bank Corporation
Message-Id: <>
Subject: Re: Ethernet Bridge
Status: RO

No, it doesn't matter ... Ethernet is a BUS topology. The placement that
doesn't work so well probably has some other problem, like not being the
correct distance down the wire (remember that 10base5 and 10base2 require
taps/connections be made at specific intervals on the wire), or perhaps
the wire is a bit out-of-spec in some spots.

To: (Lenny Simon)
Subject: Re: Ethernet Bridge
In-Reply-To: Your message of "Thu, 28 Jan 93 17:04:34 EST."
Date: Mon, 01 Feb 93 11:02:49 -0700
From: Phil Green <>
Status: RO

> My Friendly Sun Managers-
> Question:
> Does it matter where in a
> segment loop a bridge is connected?
> If so, why?

It depends on what you wish to achieve. The general reason
for adding a bridge is to localize traffic. You seperate
the hosts that talk to each other onto different interfaces.
Adding a bridge puts a device in the path that must analyze
a packet and then either forward it(which may require some
delay if the destination net is busy) or drop it if it
is for local destination.

To: (Lenny Simon)
Subject: Re: Ethernet Bridge
In-Reply-To: Your message of "Thu, 28 Jan 1993 17:04:34 EST."
Date: Mon, 01 Feb 1993 11:52:43 +0100
From: Geert Jan de Groot <>
Status: RO

Does the bridge have internal terminators?
measure the resistance using an ohmmeter Should be infinite. If it's
50 ohm, it has internal termination and replaces the terminator
at the end of the coax.

Geert Jan

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