[reSIProcate] StatelessProxy performance problem

[Alan Hawrylyshen]

On May 17, 2005, at 03.47, Moshe Matitya wrote:

> Thank you for your offer.  Please note, however, that I am  
> experiencing this behavior with the StatelessProxy app, not with  
> repro.
>
> Thanks,
>
> Moshe

The most likely culprit for performance problems are slow or poor DNS  
setup.
For every request of the form:

     sip:user at host.org

The stack will do a NAPTR query on host.org, followed by a series of  
SRV and ultimately A record queries.
If you do not have NAPTR or SRV records, this will result in 2 DNS  
query RTT delays before the A record query.
You can avoid this by setting up the DNS records for the SIP server  
as described in RFC 3263.
Additionally, running a 'near' caching nameserver can be a real help.  
Smarter BIND 8/9 servers will include A records in the SRV results as  
additional information, avoiding the need to do extra queries.

Alan