BRIDGE - An Ethernet Bridge with error injection
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BRIDGE is a simple packet bridge with error injection. It copies packets
back and forth between two network interfaces, and inserts errors (lost
packets) in a defined and reproducable manner. This is useful in the
testing of ethernet communications under various error rate conditions.

BRIDGE interfaces to the ethernet card via two standard DOS packet drivers,
these drivers must be supplied by your ethernet card manufacturer, and are
included with most cards. See your network card documentation and software.

Packet drivers for a large assortment of ethernet cards are also available
from:
    Crynwr Software    11 Grant St.    Potsdam, NY 13676
This collection is available on SIMTEL and other software archive sites
under the filenames: PKTD*.ZIP (or whatever archive format is used)

You can also try the originators of the packet driver specification:
    FTP Software, Inc.   26 Princess St.   Wakefield, MA  01880-3004
    (617) 246-0900
for more information.


RUNNING BRIDGE
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Install the packet drivers for your network cards in accordance with the
card documentation. If possible, use the standard packet driver software
interrupts of 96 (0x60) and 97 (0x61)... If you use a different interrupts,
you will have to specify the interrupt to BRIDGE via a command line switch
every time you start it.

Use:    BRIDGE  [options]

Opts:   E1=rate,npkts,maxtime  = Set <<< error injection
        D1=delay,packets       = Set <<< delay function
        E2=rate,npkts,maxtime  = Set >>> error injection
        D2=delay,packets       = Set >>> error function
        I1=n (decimal)         = Set <<< packet driver interrupt
        I2=n (decimal)         = Set >>> packet driver interrupt


"<<<" refers to traffic from interface 1 to interface 2
">>>" refers to traffic from interface 2 to interface 1

The following parameters may be set for each interface, and also altered
interactively in real-time:

Erate:      This is the rate at which errors are injected.
            It is specified as #packets+/-RandomFactor
            For example, setting: Erate: 100+/-10
            means that an error event will occur every 90-110 packets

Pkts/Event: This controls how many packets will be dropped for each
            error event. It is specified as #packets+/-RandomFactor
            For example, setting: Pkts/Event: 5+/-2
            means that between 3 and 7 packets will be dropped when
            each error event occurs.

MaxTime:   This is the maximum duration of an error event. The bridge
           will stop dropping packets after this many milliseconds, even
           if the specified Pkts/Event has not been reached.

Delay:     This specifies the time (ms) that the bridge will wait after
           forwarding a packet before the next one will be sent.

Pkts/Delay: This specifies the maximum number of packets which will be
           buffered by the bridge (max. 250) for delayed output. If more
           that this number of packets is queued, transmission will
           commence. 

Note, BRIDGE was designed for testing in a voice application which uses
SMALL packets. BRIDGE will not process any packet which is greater than
242 bytes in size (256 - the 14 byte header).


Dunfield Development Services (DDS) offers software and firmware
development services specializing in systems and embedded applications.
For more information, visit: http://www.dunfield.com
