Bulletins from the Pacific Packet Radio Society - page 004

The callsigns of the sender and receiver will be located in the options field, using two of the unassigned control option numbers. Thus the packet header will consist of the standard 20 bytes plus 12 to 16 bytes of options containing the sending and receiving callsign. Explicit routing of messages is still permitted through use of the source routing option.

Some of the complexity of the INTERNET standard could be reduced by restricting use of the following features:

Fragmentation - Breaking up a packet is not necessary if the buffer allocation is large enough. The standard specifies a 576 byte maximum packet size.

Service Type - This is an option which can be ignored. Useful for interactive vs. batch traffic, or priority message handling.

Security Option - Not required in our network.

Stream Id - Not required

Timestamps - Optional

When we eliminate the requirement for the above items, we really have a basic set of features which are needed for an easy-to-use and versatile network service. Some of the features, such as error reporting, will be necessary to help people figure out what's going on. Other optional features will be useful in testing and measuring network performance.

So, there's a proposal on the table. Can we get some comments?

Best regards,

Hank Magnuski, KA6M

FILE QST.81.08.3l.0.VE7APU

David Altekruse, W6RAW

Hi Dave,

In regards to your inquiry as to what we have been doing with S-100 8273 boards. Yes, we have made two S-100 wire-wrapped boards here. The first board was designed to operate on an Altair 8800 mainframe using the original Altair 8080 cpu card. This was built a couple of years ago and worked successfully. It used the Intel 8259A priority interrupt controller and the intel 8253 triple interrupt timer in order to provide for line timeouts, transmit-receive switching timeouts and a time-of-day clock. it had a single 8273 as well. The problem with this board was that it only had one channel and was only suited for use with an 8080.

More recently, we have built an S-100 card with many more features than the original card. Here is a list of some of the

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