X-Git-Url: http://dxcluster.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=perl%2Fproto.html;fp=perl%2Fproto.html;h=b0328de4905103650033b7639f00380b98957c04;hb=11056ea11fce910aa0e0d183a1cce73cf0de1c21;hp=0000000000000000000000000000000000000000;hpb=3ac88c21abe28b60bd5b26a8dae2474ad3e81f8a;p=spider.git diff --git a/perl/proto.html b/perl/proto.html new file mode 100644 index 00000000..b0328de4 --- /dev/null +++ b/perl/proto.html @@ -0,0 +1,137 @@ + + +
++
Field | +Description | +
OP Code | ++ This will be 'B' for now, but will be extended when multicasting + comes into being + | +
From Address | +
+ This will always be the originating cluster callsign and shall
+ |
+
To Address | ++ The To address can be anything at all that is likely + to be meaningful to a cluster program, it could be a callsign, a 'group' name of + some sort (eg 6MUK) or it could be empty, indicating a broadcast + | +
Date/Time/Count | ++ This is a unix time_t, in hex (ie 8 characters) with an optional + 2 byte hex count on the end which can allow up to 256 protocol messages to be originated + a second. Programs must allow for both 8 or 10 digit hex numbers + | +
Data | +
+ The actual cluster data. The data in this field can contain only
+ ascii data. Any non ascii data shall be converted to %XX format, where
+ XX is the hex equivalent of the character represented, certain special
+ characters in the data such as '%', '|' and '^' shall also be converted. Although
+ it is envisaged that most data will be ascii, things like mail files can and
+ will contain newline characters and these will be converted.
+ It is suggested that the raw version of the data in this packet be no + more than 128 characters, if it any packets are likely to be routed over + ax25 bearers. However, programs should be prepared to accept 1024 characters (after + decoding) for point to point wire links and routed data. + |
+
Checksum | ++ This is calculated as the simple arithmetic checksum, modulo 256, + of the whole packet excluding + this field and any preceeding field separator, as two hex digits + this checksum is designed solely to pick up errors in any connections between + this protocol and lower layers - where hopefully real CRC checking is done + | +
+ Each field in the above packet shall be separated by the '|' character EXCEPT the + op code which is concatenated onto the from field. The '|' character + must not appear in any field in the overall packet, it is the data providers responsibility + make sure this happens. If it is necessary for operations there can be a locally generated + newline sequence added on the end of the packet for sending or delimiting purposes + which is stripped off before presenting the packet for decoding. +
+ +
+ A typical packet might look like:-
+
+ BGB7DJK||8BCF65DE|DX^G1TLH^M0BAA^144123^Humungous Signal!|A8
+
+ BGB7DJK|SYSOP|8BCF65FC|AN^G1TLH^What @$%7C%5E!** condxs?|5C
+ BGB7DJK|GB7BAA|8BCF670102|TA^G1TLH^G8TIC^Baaaaaaaaaaa|FD
+
+ +
+ As mentioned earlier, astute readers will see that there is a mix up of lower + layer data with higher. This is deliberate (as well as potentially messy), but it saves + characters and promotes regularity on format. Apart from anything else, most directed + data actually needs to pass from cluster to cluster and it is important for the higher + layers to know where a packet originated. Also higher layers need to address packets to + other clusters or groups and there would otherwise be considerable duplication. +
+ ++ If a packet fails a checksum, then it is silently dropped - for now. When reliable + multicast comes in, other actions will occur at this level. In any event, higher level + functions that require some state to be maintained between packets (eg mail transfer) + should make their own arrangements in case reliable multicast isn't available between + two cluster nodes. +
+