Using the Wisconsin Network - Part 2
		       by Andy Nemec, KB9ALN

      In Part one of our series, we discussed what digipeaters and
 nodes are, the different kinds of nodes, and what makes them so
 special. In Part Two, we will continue our discussion.

      Let's review. A digipeater is a simple repeater of packets. A
 node is a more sophisticated repeater of packets, it knows if a
 packet was received, and can often allow you to send your packets
 over a very long distance. A network node is linked to other nodes
 and is often capable of doing more than just repeating your
 packets.

      We've talked about using nodes to pass our packets a longer
 distance. However, the need for a network of nodes grew out of
 another problem closely related to this need for distance.

      You may have found that not everybody in the packet community
 is on the same frequency in different parts of the state. This was
 done on purpose, so that people would not crowd up on one
 frequency, making it useless. Different areas of the state are
 divided up into seperate Local Areas. This is usually done by
 region, county, or even parts of a city. Each division is called a
 "LAN", meaning "Local Area Network", having a separate LAN
 frequency. Some way had to be devised so that different areas
 could communicate with each other, and that is where the network
 of nodes comes in.

     The Nuts and Bolts of a Node system.

      A node in it's physical form is a TNC, a Radio and the
 antennas it needs to work, similar to other packet stations. The
 TNC is specially modified with a different set of operating
 instructions. Some garden variety TNC's have a node built in, like
 a Kantronics TNC. Network nodes are most often dedicated TNC/Radio
 Combinations set up specially for the purpose.

      Network nodes are also connected, by Radio, by wire, or by
 both. Nodes connected by wire at one location form a "Node Stack".
 The node radios in a particular stack operate on different
 frequencies and all "Talk" to each other, and with other node
 stacks. They exchange information concerning their ability to
 contact other network nodes. Network Nodes that contact each other
 over the air usually do so on dedicated frequencies reserved for
 Node-to-Node communication. This is called a "Backbone", and is
 devoted to connecting different nodes together so that your
 packets can be passed a greater distance and to other LAN
 frequencies.

      The chart below will demonstrate a pair of network node
 stacks that carry packets between 2 LANS by way of a backbone. One
 node stack shown actually has access to 2 backbone frequencies,
 one on VHF, one on UHF.

		    ------------------------------------
		    |     ^ High-Speed Radio Link ^    |
  ----------    ----------                        ----------
  |  WIGB  |    | #446GB |                        |  #APL4 |
  |  VHF   |----|   UHF  |                        |   UHF  |
  |Backbone|    |Backbone|                        |Backbone|
  |  Node  |    |  Node  |                        |  Node  |
  ---------- ^  ----------                        ----------
      |< Wire Link >|                                  | < Wire Link    
  ------------------------                  -----------------------
  |  WIGRB VHF LAN Node  |                  |  WIAPL VHF LAN Node |
  |     145.070 MHz.     |                  |     145.650 MHz.    |
  ------------------------                  -----------------------
   Green Bay Node Stack                       Appleton Node Stack

      If you guessed that the people in Green Bay can connect to
 the people in Appleton even though they are on different
 frequencies, you are right. Other LANS can be arranged so that
 they, too are on the backbone. 

      This is the basis of a packet radio network. In the next part
 of this series, we will put this knowlege to work. We'll use
 information you can get from a node in order to explore the
 network. 
 
 *End of part 2*