[Serdev] Concept for a SIP cluster implementation

[Klaus Darilion]

Jan Janak wrote:
> On 27-09-2005 17:48, Klaus Darilion wrote:
> 
>>Andreas Granig wrote:
>>
>>>Klaus Darilion wrote:
>>>
>>>
>>>>So, we just have to make ser call-stateful first :-)
>>>
>>>
>>>Yes. Any volunteers? ;o)
>>>
>>>
>>>>>I'd say it's much easier to handle if the outbound proxy equals the 
>>>>>registrar from the UACs point of view. So the UAC always sends all 
>>>>>requests to the same edge proxy, which then splits up REGISTERs from 
>>>>>other requests and forwards them to the appropriate server.
>>>>
>>>>
>>>>
>>>>Of course it would be much easier. How will you handle load blalancing 
>>>>between the edge proxies? SRV? If you use SRV, the clients are free 
>>>>send the request to whatever edge proxy. RFC 3263 says to use SRV 
>>>>lookup for each transaction.
>>>
>>>
>>>I don't want to use SRV, not only because of the NAT problem but also 
>>>because most of the SRV implementations in UACs I've seen so far are 
>>>broken, if implemented at all.
>>>
>>>So each edge proxy will be set up with a hot-standby proxy for IP 
>>>failover, so there's no need for a failover mechanism in the UAC (to be 
>>>as much independent from it as possible).
>>>
>>>If the first edge proxy pair (say sip1.my.domain) get's to a limit 
>>>regarding ressources, you can add a second pair and propagate the new 
>>>hostname (sip2.my.domain) to new customers.
>>
>>Thus, you solve the problem by provisioning. Btw: Openwengo (cross 
>>plattform SIP phone) fetches all the SIP provisioning from the service 
>>provider using https. Thus, it would be easy to change SIP configuration 
>>and host certain accounts on certain SIP proxies. I like this.
> 
> 
>   I don't like it because:
> 
>   - People should be allowed to use any SIP UA as long as it is RFC3261
>     compliant. And there never will be single widely accepted standard
>     for provisioning.

Yes they should, but I really like the user experience - it is as easy 
as installing Skype.

>   - Doing central provisioning on a large scale is difficult,
>     especially in heterogenous environment.

But I think it is worth the trouble as you save lots of support requests 
from customers.

klaus