Robustness of bus overlays in optical networks

Local area networks (LANs) nowadays use optical fiber as the medium of communication. This fiber is used to connect a collection of electro-optic nodes which form network clouds. A network cloud is a distribution network that connects several external nodes to the backbone, and often takes the form of a star or tree. Optical stars and trees have expensive and inefficient recovery schemes, and as a result, are not attractive options when designing networks. In order to solve this problem, we introduce a virtual topology that makes use of the robustness that is inherently present in a metropolitan area network (MAN) or wide area network (WAN) (long haul network). The virtual topology uses a folded bus scheme and includes some of the elements of the real topology (architecture). By optically bypassing some of the router/switch nodes in the physical architecture, the virtual topology yields better recovery performance and more efficient systems (with respect to cost related to bandwidth and recoverability). We present a bus overlay which uses simple access nodes and is robust to single failures. Our architecture allows the use of existing optical backbone infrastructure. We consider a linear folded bus architecture and introduce a T-shaped folded bus. Although buses are generally not able to recover from failures, we propose a loopback approach. Our approach allows optical bypass of some routers during normal operation, thus reducing the load on routers, but makes use of routers in case of failures. We analyze the behavior of our linear and T-shaped systems under average use and failure conditions. We show that certain simple characteristics of the traffic matrix give meaningful performance characterization. We show that our architecture provides solutions which limit loads on the router.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2002

Author dc:creator

• Libarikian, Ari Levon, 1978-

Advisor dc:contributor.advisor

• Muriel Médard.

• Electrical Engineering and Computer Science.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/16850

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/16850