~srini / research

Optical Networks

Over the last few years, our research in optical networking has concentrated several aspects:

  • Analytical modeling for evaluating blocking performance (1) with heterogeneous switch architecrues; (2) with physical layer constraints (specifically, wavelength usage constraint); (3) for multi-rate traffic; and (4) for establishing multicast trees.
  • Dynamic routing in wavelength-routed networks.
  • Protection strategies using (1) failure dependent protection; (2) link protection at connection granularity; (3) diversion protection; (4) supporting multiple protection strategies for providing protection based on recovery time requirements; (5) with partial information availability on wavelength usage.
  • Failure localization in optical networks using monitoring cycles and paths. This work appeared in INFOCOM 2008. Click here to read more on this work.


Multipath Routing

The objective of multipath routing is to route packets from a source to a desired drain along link- or node-disjoint paths with minimum routing table overhead. We have developed a technique called "colored trees" that achieves disjoint multipath routing with the minimum overhead possible, i.e., twice the routing table size required for traditional single-path routing. The colored tree approach constructs two trees, namely red and blue, rooted at a drain such that the paths from any node to the drain on the two trees are link- or node-disjoint.

We have developed the first known distributed algorithm to construct the colored trees whose running time is linear in the number of edges in the network. Refer to our IFIP Networking paper for more details.

The above work has been further extended for routing to two disjoint drains [GLOBECOM 2006] an to two-out-of-K drains in a multi-drain network [INFOCOM 2007].

We extended the concept of colored trees to recover from two link failures, using tunneling. For more details, refer to our INFOCOM 2009 paper.



Wireless/Sensor Networks

Our research in sensor networks focuses on: (a) understading the coverage time characteristics [MASS 2006]; (b) maximizing coverage time in location unaware networks [IFIP Networking 2007]; (c) robust coverage in location unaware networks [SECON 2007]; (d) node clustering [Network 2006]; and (5) bounds on lifetime and node density in multi-modality sensor networks [ADHOC 2009].

In wireless networks, we have developed retransmission and backoff strategies for broadcasting [ADHOC 2009],. In addition, our work on multipath routing has been applied to wireless/sensor networks [GLOBECOM 2006, INFOCOM 2007].