My main area of work is Multimedia Networks, i.e., systems that are capable of exchanging multimedia data in real-time. The typical use-cases are Live Streaming, IPTV, Voice and Video calls (VVoIP), Group Communication, Telepresence, etc. The limitations vary between use-cases but are mainly: Scalability, Timeliness and Resource Control/Management.
Scalability means delivering the multimedia stream to one or to millions of users. Timeliness means delivering the data within a defined time – you wont like it if your friend across the globe knew that the team scored a goal before you did. Resource Control means to optimize the usage the available resources (CPU load, sending rate, encoding complexity, decoding buffers, forwarding relationships, etc.). In some use-cases, we can optimize only 2 out of the 3 limitations, this leads to trade-offs.
I am currently working on:
- Multipath RTP (MPRTP): Modern systems are often multi-homed but most systems use only one of their interface at any given point of time. This is similar to MPTCP but for real-time media data. We are working towards a demo to show that the multiple interfaces can be used to Increase either Throughput or Reliability or some combination of both. Direct applications of MPRTP can be (a) higher quality video streaming, (b) achieving higher scalability and resilience by using Multiple ALM trees.
- Rate-control and Error-resilience mechanism for mobile video calls in heterogeneous environments. This is ongoing work since 2006, when mobile video calls was in its infancy. Video call quality over 3G networks has been poor, but is rapidly improving (since Spring 2010). This may be because of increasing broadband subscribers (last-hop capacity is increasing), Skype‘s exit from eBay and its march towards an IPO, introduction of Facetime by Apple Inc.
IETF contributions: http://www.arkko.com/tools/allstats/varunsingh.html