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1992-05-27
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What is the ROSE X.25 Packet Switch?
The ROSE Switch is the first Amateur Packet Networking program that
uses the International Standard protocol for packet networks, CCITT X.25.
The program is meant to be installed in place of the EPROM found in a TNC-2
(or Clone) packet controller. It is not meant for User Terminals, but for
Network Facilities such as a Digipeater, a NET/ROM, or TheNet EPROM.
ROSE X.25 Packet Switch offers the following features:
* Hop-by-Hop Acknowledgements between Switches - provides reliability
and higher throughput.
* On-line Information - Information/Help bulletin.
* FCC and foreign PTT acceptable AX.25 Level 2 SOURCE and DESTINATION
Identification - the call signs of both the station of
origination and termination appear at each end of the connection.
* Proper Transmitter Licensee Identification - Switch always
identifies its transmissions with its own call sign, not the call
sign of ANY user. Call signs traverse the network without ANY changes.
* Backbone is Fully Transparent to Users - Can add or remove Switches
in the backbone, change call signs, bands/frequencies without
having to inform users or modify BBS forwarding files.
* True Implicit Addressing - Only need to know the address of the
desired exit point of the network, not all the intermediate
steps.
* Network Determined Routing - Network manager determines best path,
eliminating need for broadcasting of routing information to other
switches.
* Dynamic Route Selection - Network will automatically attempt
alternative paths to remote switches, based on information that
the Network Manager provided.
* Predetermined Network Paths - Network manager tells each switch
which paths to use, will not attempt impossible links because
another switch was heard during a band opening.
* Support for Emergency Operations - A switch can be added to the
network to provide service from the afflicted area without
modifications to the existing network.
* Security System for Remote Control - authentication of user who
requests to view or modify configuration.
* Common Hardware base among vendors - The ROSE X.25 Packet Switch
runs on ANY TNC-2 compatible TNC, (TAPR TNC-2, AEA PK-80, MFJ
1270, Pac-Comm TNC-200 Tiny 2, Micro-Power, as well as the Pac-
Comm DUAL Port DR-200)
* Full Radio Support on Asynchronous Port - The Asynchronous port of
a TNC can be attached to a 202, or any other modem with an RS-232
interface and Radio, providing a dual port system. The second
port is AX.25 using the Asynchronous Framing Technique (AFT) that
was proposed by Toby Nixon of Hayes, which is pending CCITT
adoption as the accepted method for sending X.25 over
asynchronous links.
* Multi-Synchronous Ports using TNC's - Since the Asynchronous port
has full radio support it also can support one or more switches
via a special (commonly available) RS-232 cable.
* Complete Remote Configuration - All configuration is done over the
air, many parameters can also be burned into the EPROM.
* Battery Backed Up Configuration - All configuration and routing
information is retained when the power is removed. No need for
manual intervention when power is restored.
The ROSE X.25 Packet Switch is the most advanced network level package
for the TNC-2 (and Clones) with support for the PacComm DR-200 Dual port,
and soon 4 port operation. The ROSE Switch also supports asynchronous
packet on the RS-232 port of most TNCs, which can either be used over the
air or tied back-to-back with other ROSE Switches.
The ROSE Switch is the only Amateur Networking package based upon the
International Standard protocols, as defined by CCITT and ISO.
The ROSE Switch fully conforms to FCC identification requirements, and does
not waste channel bandwidth with needless broadcasts or beacons and has
lower protocol overhead increasing actual data throughput.
The ROSE X.25 Packet Switch does not have to have separate ID Beacons, nor
does it need to go key down for hours (so it seems) broadcasting network
routing information. The ROSE Switch does NOT speak unless spoken TO!
You do not have to guess what station a transmission came from, since the
call sign of the switch appears in every transmission.
You do not have to poke your way through the network, paging through obscure
node names to try to get to the town you want to reach, nor do you need
reams of network maps: your phone book will do.
The ROSE X.25 Packet Switch is the most advanced network level package
for the TNC-2 (and Clones) with support for the PacComm DR-200 Dual port,
and soon 4 port operation. The ROSE Switch also supports asynchronous
packet on the RS-232 port of most TNCs, which can either be used over the
air or tied back-to-back with other ROSE Switches. Clusters of switches
may be created in multiples of 5 with a Diode Matrix board (from NX2P
Electronics), or multiples of 4 or 8 with an RS-232 LAN from Pac-Comm.
Why is a Transparent Backbone Important to a large amateur packet
network?
We have learned long ago that using Callsigns for network level devices
can lead to many problems. In the early days of packet when we only had
digipeaters we could establish connects great distances (few users to
collide with!) with digipeaters, if you knew all the calls. This lead to
the network maps, that needed to be continually updated as new stations
came on the air, as well as when old stations would move off to find a quite
frequency again.
The bottom line is that if I need to communicate with a station 200+ miles away
I (as a user) should not have to keep abreast of the networking (or political)
changes made by all the packet groups along the path.
As a network manager I should only have to worry about how connections are
established within my local network, and how my network interoperates with
the networks at my boarders (RF and geographical).
The ROSE X.25 Packet Switch was designed with these problems in mind.
The following is an example showing how flexible a ROSE X.25 Network is.
Problem: Two switches are linked on the user channel and the traffic
volume has increased to the point where a trunk link is needed.
Solution: Install dual port systems at each site and add second radios to
link them.
Starting Network:
2 m
N2DSY-3 = = = = = X.25 = = = = = KA2VLP-3
201744 609426
Little Falls Hightstown
KD6TH-4 KB1BD-4
Note: KD6TH-4 and KB1BD-4 are BBS systems, but could just as well be two
users.
The 70 cm band was chosen for the link, but we found out that we needed a
higher antenna than we already had for that band. Some asking around
revealed a club (WB2JQR) tower that had a spare antenna, after some testing
we discovered the path would work, but we still needed to get connectivity
from JQR to VLP. Another pair of radios needed to be found. We then found
out that Russ, N2EVW had a dual-port cross band digipeater that was being
used to access the VLP switch from 70 cm already and he agreed to let us
use it to digipeat between the two towers (VLP and JQR).
Interim Network:
70 cm WB2JQR-3
...........................609443 ...
. Cranbury \
. 2 m N2EVW-2
N2DSY-3 = = = = X.25 = = = KA2VLP-3 = = =
201744 609426
Little Falls Hightstown
KD6TH-4 KB1BD-4
Once the new radios are in hand, we are really waiting for crystals, we can
have the JQR tower and the VLP tower link directly.
Final Network:
70 cm WB2JQR-3
.................................609443
| Cranbury
| 2 m |
N2DSY-3 = = = = = X.25 = = = = = KA2VLP-3
201744 609426
Little Falls Hightstown
KD6TH-4 KB1BD-4
In all of the above backbone changes, none of the users or BBS's needed to
be notified to make any changes, since the network access points maintained
identical connectivity.
Each CPU (ie. TNC) needs its own call sign. You can reuse a call sign if
they are on different frequencies or do not share another switch in the RF
domain.
I hope you find preceding example useful to show how flexible a network of
ROSE X.25 Packet Switches can be.
73, Tom
W2VY@KD6TH
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