Previous Employment

Research Staff Member, NEC C&C Research Labs , Princeton, May 95 - Oct 99

• ['96 - '99]Designed and implemented the mobile  IP/ATM  protocol architecture for one of the first  25Mbps mobile broadband  networks based on wireless ATM. In addition, the core network was also designed to support non-ATM wireless access such as wLAN and GSM.  I provided a core set of ATM Forum contributions on extending  ATM signaling/routing protocols for  "mobile ATM" in the wireless ATM working group, and supervised an offshore development team for lab trials of this IP/ATM mobile broadband sytem with two large carriers.
  
  
  
  
  • Demo of  WATMnet system at  Wireless Broadband Testbeds (DEMO '98) , Oct '98
  • Early prototype demonstration of Mobile ATM prototype at ACM Mobicom'96
  • A presentation describing the overall  WATMnet system :  my contributions comprise  the network protocol architecture/implementation.

   

Patents :

Handoff control for point to multipoint connections in mobile ATM networks.
US Patent 6,643,279. Co-inventors : J. Li. Nov 2003

Handoff method for an ATM wireless network wherein both the switch and the mobile buffer cells and the mobile controls when the handoff will occur.
US patent 6,023,461. Co-inventors : J. Li, D. Raychaudhuri. Feb 2000.

Handoff-control technique for wireless ATM.
US patent 5,974,036. Co-inventors : J. Li, D. Raychaudhuri, R. Yuan, S. K. Biswas. Oct 1999.

 

Representative Publication :

Mobile ATM : architecture, protocols  and  implementation. 2nd IEEE Intl workshop on broadband  switching systems,  Dec '97.  A. Acharya, J. Li and D. Raychaudhuri.


[Complete list of publications available here]

• ['96 - '99] Responsible for design/implementation of Ipsofacto, an IP switching technology that was a precursor to MPLS  whose key feature was support for IP multicast.  In conjunction with  Mobile IP and RSVP,  Ipsofacto  provided an IP based protocol architecture for  the WATMnet system.  I supervised a eight-person offshore development  project  (Feb - May'99) for deployment of Ipsofacto in the above trials.
  
  

• IP Switching over ATM project with GMD Fokus and trial of Ipsofacto connecting  NEC Princeton, NEC Berlin and Berkom.

 

Patents

System and method for transferring IP packets using fast ATM cell transport.
US patent 6,343,326 Co-inventors : R. Dighe. Jan 2002.

Method for Internet Protocol switching over fast ATM cell transport.
US patent 5,903,559. Co-inventors : R. Dighe. May 1999.

 

Representative Publication:

IP switching over fast ATM cell transport  (IPSOFACTO) : Switching multicast flows . IEEE Globecom '97. A. Acharya, F. Ansari and R. S. Dighe

[Complete list of publications available here]

• ['96 - '97] An open architecture for IP/ATM switches and  base-stations, with separation of networking software(running on an external Linux PC) from the switching hardware,  using GSMP  (Generalised Switch Management Protocol) as the control interface, thus enabling a choice of either IP or ATM protocol stacks to control a common switching  hardware.  In 1996, this was one of the earliest use of open-source software (Linux and Linux-ATM stacks), for  networking projects in the industry.
  
  

Quality of service and resource reservation in IP networks with mobile flows

Quality of service for flows in a IP network is achievable by explicit resource reservation within the network using protocols such as RSVP. However, when IP endpoints are mobile, the path of such flows change everytime a mobile host changes its acess point. Without re-doing the reservation end-to-end, RSVP can be enhanced to partially tear down an existing reservation and only setup a reservation for part of the new path (MRSVP). In a second part of this work, a related problem was addressed : a mobile host may have reservation for resources in one cell but may lose that reservation in a new cell after a handoff. We extended the Integrated Services architecture for QoS to define new classes of service for mobile hosts : mobility independent and mobility dependent predictive service, and a mobility independent gauranteed service.We proposed an admission control scheme to achieve high utilization of network resources given a sufficient degree of multiplexing of mobility independent and dependent flow. This work formed the PhD thesis of Anup Talukdar at Rutgers University, currently at Motorola Labs.

Publications :

MRSVP : A reservation protocol for integrated  services packet networks with mobile hosts. ACM/Baltzer Journal of Wireless Networks, Vol. 7, Issue 1, Jan 2001.  A. Talukdar,  B. R. Badrinath and A. Acharya.

Integrated services packet networks with mobile  hosts : architecture and performance. ACM/Baltzer Journal of Wireless Networks, Vol. 5, Issue 2, Mar 1999.  A. Talukdar,  B. R. Badrinath and A. Acharya

Rate adaptation schemes in networks with mobile hosts. The fourth annual ACM/IEEE international conference on Mobile computing and networking (Mobicom), Oct 1998.  A. Talukdar,  B. R. Badrinath and A. Acharya.

On accomodating mobile hosts in an integrated services packet network. IEEE Infocom '97. A. Talukdar,  B. R. Badrinath and A. Acharya.