Setup:
------

HOSTA ---------- siproxd ------------HOSTB
private net         |     Internet


siproxd must be setup as transparent proxy (iptables rules to
redirect all outgoing SIP traffic from sipp to HOSTB to local siproxd)

Client on HOSTA
---------------
- limited to 10 simultaneous calls (-> default configured RTP port range)
- server and client are on port 5070
- each call is kept for 1000ms (-d), then terminated
- every 1000ms (-rp) 5 (-r) new calls are spawned
- end test after 100 total calls

./sipp -sf myuac.xml -l 10 -p 5070 -d 1000 \
       -m 100 -r 5 -rp 1000 HOSTB:5070 


Server on HOSTB
---------------
- port 5070

./sipp -sf myuas.xml -p 5070


Note: siproxd has limited simultaneous calls
      - RTP port range
      - some compile time constants for RTP array sizing

Those XML scenarios include a REGISTER step before doing the
actual call. This is required for siproxd to know the local UA.