Using *RT for HA purposes was: [Asterisk-Users] Realtime MultipleAsterisk boxes, iaxusers

[Peter Bowyer]

On 04/01/06, Alistair Cunningham <acunningham at integrics.com> wrote:
> Peter Bowyer wrote:
> > I was thinking along the same lines, but for a dynamic setup it should
> > be possible to have SER/OpenSER load balance REGISTER requests
> > according to some strategy/metrics, and then forward INVITEs and other
> > call-related traffic to the 'right' back-end server.
> >
> > Probably lots of reasons why this is too complicated, though....
>
> One being that it must be the device that NAT phones register with that
> delivers calls to them. Otherwise, the NAT device sees a packet coming
> from an unknown IP address and drops it (for common types of NAT such as
>  restricted cone).

Yes, that's the sort of reason I was thinking of :-)

I guess you could NAT the whole cluster behind a single IP with some
fancy firewall/router rules....

> Since SER needs to deliver calls, it really needs to
> be SER that accepts REGISTERs and holds the registration information.
> The Asterisks then send calls from phones to the SER heartbeat address
> for delivery.

And if a lot of the calls are SIP-SIP, I guess - why bother Asterisk
with them at all...

> This is what we do in our ITSP in a box product. It gives us full
> redundancy and failover with the registration capacity of SER and the
> features of Asterisk.

Sounds good.

> For very large systems, it's possible to have SER redirect (with load
> balancing) REGISTERs to a set of SERs so that NAT devices know about the
> machines their phones are registered on, but this takes great care to
> get right in all cases.

Yeah - I knew this was harder than it looked :-)

Peter

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Peter Bowyer
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