[aprssig] Msg reply path

[Stephen H. Smith]

On 10/6/2013 4:22 PM, Andrew P. wrote:
> I understand what a SS7-3 would do, but why not use a SS3-3 to begin with?

That's why I was asking whether a digi repeating SS7 should also repeat SS6, 
SS5, etc.

Yes, it will with no special steps taken.

Digis are not normally configured to process specific explicit values of N-n. 
You only specify the base "callsign" of the path such as WIDEn-N, SSn-N, 
TEMPn-N etc.  The digi will then automatically process any values of n-N that 
follow the base callsign.

In classic TNCs like KPC3s, TNC2s, etc the UIFLOOD command is used to specify 
what base callsign element(s) should be acted on and decremented. For example

UIFLOOD WIDE,SS

would cause the digi to process any value of WIDEn-N and SSn-N by decrementing 
the N value and then retransmitting the packet.



More recently, as part of the "new paradigm" initiative,  the separate TNC 
command MYALIAS has been used to trap and truncate abusively long paths. The 
MYALIAS command processes the path element as a literal exact-match callsign 
(WITHOUT n-N decrementing) "eating" the entire "callsign" including the n-N 
values, in a single hop.

You load up the MYALIAS list with something like

MYALIAS  WIDE1-1,WIDE7-7,WIDE7-6,...WIDE6-6,WIDE6-5,.. etc

Entries in MYALIAS are NOT processed sequentially -- any exact match to ANY of 
the values after MYALIAS will trigger a digipeat with the path element marked 
fully used, rather than being decremented.

[Note that a "first hop" low-level home fill-in digi would enter only WIDE1-1 
into MYALIAS , and NOTHING into UIFLOOD.]

For example a first-hop digipeat on the path " WIDE7-7 " would be digipeated as 
" WIDE7-7* " killing any further digipeats by other digis.