[asterisk-users] Unique call ID's across several systems

[Matt Florell]

On 10/24/06, Steve Edwards <asterisk.org at sedwards.com> wrote:
> On Sat, 21 Oct 2006, Jeremy McNamara wrote:
>
> > Steve Edwards wrote:
> >> I have a farm of 7 1u's) with te410p's. When a call comes in, I call an AGI
> >> that creates a channel variable named GLOBALID. The GLOBALID is 2 digits
> >> for the host number, 2 digits for the channel number, and 8 characters for
> >> the UNIQUEID encoded in hex.
> >>
> >> Then, I stuff it into CALLERID(name) so it will be available as the call is
> >> sent (using dial()) to the application servers.
> >
> > AGI is not going to scale.  Why not do it all with dial plan logic? Store a
> > global system id for each system and concat it onto the uniqueid CDR value.
>
> Our need for a globalid (in addition to our needs) was mandated by our
> credit card processor. They also limited us to length, upper case letters
> and digits -- not even a lowly period was acceptable to them :)
>
> To fit the host, channel, and unique id in I decided to encode the unique
> as hex. This system was designed before dialplan functions and I didn't
> see an easy "dialplan way" to encode to hex, so I cranked out an AGI.
>
> I don't know how fast a dialplan implementation would be (if a hex
> function was available), but I benched the AGI approach and the server
> does 1,000 in about 4 seconds.
>
> I'm sure your knowledge of telephony far exceeds mine, Jeremy. For a
> system with only 92 channels can the telco deliver more than 92 calls in
> 0.4 seconds over PRI?
>
> The average call duration for this system is about 10 minutes, so the
> probability of all 92 channels being free at the same time is rather
> small.
>
> I always wondered how much overhead invoking an AGI incurred. Setting up
> the AGI environment, spawning a new process, parsing the AGI environment,
> doing something useful, terminating the AGI process -- it sounds like it
> would take forever. Now I know it only takes about 40 msec.

Have you tried using a FastAGI server script instead of a stand-alone
AGI script?

We saw dramatic improvement in speed and performance when we switched
our logging functions to FastAGI from AGI.

MATT---