[asterisk-ss7] A question about ISUP SAM message usage

[Johann Steinwendtner]

Tian schrieb:
> As you know, when overlap signaling is used, when enough digits have 
> been collected to identify the next exchange, an IAM is sent to the next 
> exchange along the route to the called party, the remaining digits are 
> sent in subsequent SAM messages.
>  
> My question is: how does the local exchange of the called party decide 
> whether all digits of the called party number has been collected or not 
> (i.e., how does the local exchange of the called party know whether or 
> not the SAM it received is the last one), especially when the called 
> party number is of variable length?

I depends on the type of called party I guess. If the called party supports
a message like "end of digit collection" than this would be translated
into an ACM message. e.g. if the called party is an ISDN interface
terminating to a PBX, the pbx would send a call proceeding or an alert
which will then be translated to an ACM.
If there is no "end of digit collection", than an End of dial (EOD) timer
will be used.
It depends totally on the type of gateway.

Best regards

Hans