Indigo Software
Pulver Conference VON Spring 2001, Phoenix, AZ, USA.
Open Test Network follow-up notes
Indigo Software took part in the OTN interoperability tests by providing full communications access to some of its SIP products, namely Proxy/Redirect/Registrar/Location servers and User Agents, to industry vendors backing SIP for Next-Gen packet-based multimedia communications.
Indigo Software performed interoperability tests for SIP only.
Indigo SIP UAs and servers were involved in the following Pulver test scenarios: 1, 2, 9, 10, 11, 13, 17, 18, 19, 20, 21.
Test Plan 1: Endpoint to endpoint call: done successfully throughout the duration of the OTN with SIP Phones and SIP UAs from various vendors (VocalData, Nortel, Pingtel, ADTech, Ubiquity, HearMe).
Note: we used a pure software-based DSP for the media encoding which streamed with a packetization interval of 60 ms. While receivers should be prepared to receive any number of frames per packet (see RTP FAQ http://www.cs.columbia.edu/~hgs/sip/faq/cache/102.html), this 60 ms value caused some troubles to some audio rendering systems expecting a packetization interval of 20 ms.
However, the week after VON, we decided to modify the packetization interval to the values recommended by RFC1890 (20 ms for ulaw/rtp, gsm/rtp, dvi/rtp and 30 ms for g723/rtp) so that the interworking is perfect with most of the systems.
Test Plan 2: Endpoint registration: we offered our Registrar server to SIP phones and UAs for them to register. Except for one or two end devices, the registration went through successfully for most of the end devices (same vendors as above).
Our UAs registered successfully with the other Registrar severs available (from CommWorks and Ubiquity).
Test Plan 9: SIP redirect call: offered our Redirect server to SIP end devices for testing redirect service. Tested Ubiquity Redirect server with our UAs.
Test Plan 10: SIP proxied call: after having registered SIP end devices with our location server database, we offered our Proxy server for application-layer routing of SIP calls. Done successfully throughout the OTN duration for the end devices.
Our UAs successfully made calls through the CommWorks and Ubiquity proxy servers.
Test Plan 11: SIP proxied call across 2 Proxy servers: calls went through successfully across our Proxy server when the peer outbound Proxy (the one from CommWorks or Ubiquity) was registered with our location database or when the server was designated using an IP address. Could not work with domain names due to the unavailability of DNS SRV records at the OTN.
Test Plan 13: SIP proxied call with busy indication : we didn’t bring a voice mail application as such and thus we performed a slight variant of the scenario. The execution of a CPL script loaded at the server redirected callers during busy callee conditions to a web page in which a video applet explained the duration of unavailability and allowed the opportunity to send an e-mail instead.
Test Plan 17: SIP to PSTN calls: we registered our UAs with our Registrar under a telephone number contact identification at Mockingbird’s SIP/PSTN gateway. Our UAs called that phone number and our proxy successfully routed the SIP INVITE message to Mockingbird’s gateway to go through to the PSTN world.
Test Plan 18: PSTN to SIP calls: successfully received phone calls originating from the PSTN. Our proxy routed the call towards our UA where the call was eventually established.
Test Plan 19: similar results to test plan 17.
Test Plan 20: SIP/MGCP to PSTN call: calls were placed by our UAs to the PSTN through SoftSwitches (Comgates, Nuera) controlling MGCP Media Gateways without any problem.
Test Plan 21: PSTN to MCGP/SIP call: similar results to test plan 20.
General Impression: the Pulver OTN interop tests provides more evidence of the maturity of the Voice over Packets technologies paving the way to Next-Gen fully packet-based multimedia networks.