JANET Voice Advisory Service
VAS Home | About VAS | Case Studies | Technology
Calls for Participation | Request Advice
Technology
- JANET VoIP Infrastructure / JANET Talk
- VoIP Deployments within the Campus
- Addressing, Numbering and Directories
- Skype
- External Links
JANET VoIP Infrastructure / JANET Talk
The JANET Talk service infrastructure comprises central servers that provide the call control and conference bridging function, register of users and gateway to the PSTN (for outbound calls only - due to Ofcom regulations). On the client side, JANET Talk software is required and peripheral equipment such as a headset and microphone or a webcam may be required to use all of the features. These features extend to; voice calls (including one-to-one PSTN dial-out), conferencing (including multiple PSTN dial-in via the conference bridge), video, shared whiteboard, desktop sharing, chat.
JANET Talk is a standalone system and is not designed to integrate with or replace existing telephony equipment, nor is it intended to be a telephony replacement, it will a collaboration environment.
Here's a few technical details. The voice protocol employed is SIP. The audio for JANET Talk uses the G.711 audio CODEC, requiring approximately 80kbps per stream including IP overheads. Video is provided using either the H.263 or DivX CODECs. The bandwidth requirements per stream vary depending on the resolution of the video. For multi endpoint connections (conference calls) DivX is the only video option supported. Conference video settings are based upon the capabilities of the chairperson or person invoking the conference. PSTN access is provided as “dial out” only for one-to-one calls, however when using the conference call mode, both JANET Talk clients and external PSTN lines can dial in to access the conference bridge.
There are also some FAQs here:
http://www.ja.net/documents/development/janet-talk-faqs.pdf
Example screenshots of the JANET Talk Client are available here:
http://www.ja.net/development/voip/janet-talk-images.html
A few points of clarification:
- JANET Talk is not a system that is similar to Skype, nor are we planning to offer any similar service.
- The JANET network supports routing of all IP protocols. SIP packets are routed to their destinations just like any other packet, including any VoIP servers such as for example, Asterisk. The JANET network does not provide a cheap/free gateway for SIP traffic to the PSTN.
There are also some FAQs here:
http://www.ja.net/documents/development/janet-talk-faqs.pdf
Example screenshots of the JANET Talk Client are available here:
http://www.ja.net/development/voip/janet-talk-images.html
JANET(UK) has commissioned a number of reports in areas that have been identified via the requirements gathering exercise. These reports will be completed and published later this year.
The initial set of topics that have been identified are:
- Glossary of VoIP related terms
- VoIP: What is it and Why?
- Voice and VoIP Regulatory Issues
- Interconnecting Traditional Telephony Systems and VoIP
- Interconnecting IP Telephony Systems
- VoIP on Network Operating Systems
VoIP Deployments within the Campus
- Deploying IP Telephony on Greenfield Sites
IP telephony is what is generally meant when traditional telephony is replaced with IP technologies – such as Voice over IP (VoIP) – within an enterprise or campus network. This briefing document provides an insight into the decisions behind and outcomes of deploying a VoIP system on a new campus site.
Addressing, Numbering and Directories
- ENUM and e164.ja.net - what is it?
This document defines the ENUM standard was developed by the Internet Engineering Task Force as a means of mapping regular telephone numbers to methods of contacting the user of that number over the Internet. It then covers its implementation and use, issues arising, configuration of equipment, its status within the UK and European developments.
- Report - Skype and JANET (published March 2006, reviewed Sept 2008)
The popularity of Skype has led JANET(UK)’s VAG (Voice Advisory Group) to investigate Skype's engineering and any implications for JANET. Two features of Skype – its use of bandwidth and encrypted tunnels – raise particular concerns.
VoIP Pros and Cons
There are many benefits to using voice over IP instead of a landline, but it can be hard to decide whether to cut the telco cord completely. Here are a few pros and cons to help.
Any problems, comments or suggestions regarding this page, please e-mail the VAS service manager.