Bulletins from the Pacific Packet Radio Society - page 024

a ) Identification of local subscribers for traffic entering the local net.

b) Call-forwarding - an entry for the address of a remote repeater node is available for re-routing traffic. The update of this is the responsibility of the end-user, not the repeater management.

c) Group channels - one or more group channels (which are permanent in nature) can be assigned to the terminal at logon (or update) time. This cannot be done without limit with present (amateur) hardware!

The group agreed on some general principles which may make the local network and external network "balanced".

1. HDLC framing will be used.

2. The HDLC address field will NOT be used as a unique source address. The unique HDLC source address will be deferred to the I-field. Rather, an address of FF might be used for a IIQST", and 00 for all sessions. This usage is still undetermined.

3. The HDLC control field will be used as-is. We hope that the overall network will support the principle of POINT-TO-POINT ACKNOWLEDGEMENT. It is felt that to do otherwise would be wasteful of network resources. For instance, it would be undesirable for acknowledgement and message numbering to be postponed for the end user-terminals in a coast-to-coast multi-hop channel. Each repeater must number packets with INDIVIDUAL NUMBERING for each connection. The implications of this is that the local and internode repeaters must maintain separate control blocks for each session in progress; the control blocks must reflect the number of packets sent and the number received. Since two terminals communicating through a repeater must establish a channel with the repeater, each session via repeater must have two control blocks. The number sent and received can be different from the standpoint of the repeater and the terminal nodes.

4. The HDLC information field will contain a header for both local and non-local service. The first two octets a re reserved for supervisory information. This is to be followed by up to four addresses of 7 octets each. The first two addresses are mandatory; these are the source and destination addresses (terminal node addresses). Repeater source and repeater destination addresses may follow this (optionally) for non-local service. The first address, which is the terminal node source address, will serve as the HDLC source address in local transactions. Note that this still allows for group addressing.

5. The packet length used in local networking should not be fixed at, say 128 bytes. Rather we should allow variable length packets, up to a maximum of about 512 or 1024 bytes. This will maintain high efficiency locally. The maximum number of bytes per packet may be revised upward if a local high baud-rate repeater can be realized.

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