List, I would like to start a development to fully implement an ISUP channel for Asterisk using Media Gateways (Cisco AS53xx/54xx for starters) as the PSTN interface. I propose implementing F-links by using Asterisk as the CA, and the Cisco (say AS5350) a the gateway taking in the PRI circuits with bearer and signalling channel(s). Then, the integrated SLT feature of the gateway would be used to drop-and-insert the channel(s) carrying signalling channel(s) and backhaul this utilising SIGTRAN or similar over to Asterisk. On the Asterisk side, the channel code would implement the necessary dual-state-machine needed to map ISUP messages back and forth with VoIP, and use SIP (initially) as the VoIP side presentation. Little query here is that whether or not the SIP code within Asterisk can handle 3rd part call control; if this is the case, then life is much easier: the Cisco can be controlled as a UA, encapsulating the ISUP messages in SIP envelops sent over to Asterisk. If this is not possible of feasible, then how about doing all of this should be doable utilising the MGCP GC component of Asterisk. I tired raising this on the asterisk-dev channel, but everyone seemed more interested in taking the mick and payment by pints of beer thank talking code. Or is it just me ? Oh, then there is the bounty: besides putting in the time, dev effort ..etc, I am offering a $5,000 for the first mile-stone, that being an Asterisk CA controlling a Cisco AS53x/54xx to process ISUP messages backhauld to the latter over SIGTRAN or similar. Thanks, Ahmed Naji Tech. Director 5G Networks LTD Send instant messages to your online friends http://uk.messenger.yahoo.com
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