Sethuram Balaji Kodeswaran

Utilizing Semantic Tags for Policy Based Networking

Policy based networks provide high levels of flexibility by allowing definition of packet handling rules within a network, resource allocation strategies, network management, or access control. Commonly used policy specification mechanisms are, however, limited in their expressibility and rely mostly on packet headers that convey limited information about the semantics of the content. We propose a new model for policy based networking that utilizes the W3C Web Ontology Language tags carried in data packets that can provide detailed semantic information about the packet or stream. Using this model, a policy decision point can reason over these tags and infer the correct set of operations to invoke. Policies are expressed in the W3C Semantic Web Rule Language using a common ontology and take into consideration the content of the streams, relevant contextual information and external domain constraints. Using this framework, fine grained, highly specialized services can be offered within the network that are context-aware, easy to manage, deploy and verify for consistency.

Enforcing security in semantics driven policy based networks

Security is emerging as an important requirement for a number of distributed applications such as online banking, social networking etc. due to the private nature of the data being involved. Further more, the wide spread use of portable devices such as laptops, PDAs etc. allows users to make meaningful ad hoc collaborations. Traditional security solutions are not feasible for these scenarios due to the varying nature of the collaborations in terms of entities involved and their roles, available resources etc. Under these circumstances, we need generic solutions that take into account the semantics of the collaborations in determining the set of allowable operations. In this paper, we propose an extensible framework that uses semantics driven policies for enforcing security. Our policies are rooted in semantic web languages which makes amenable to interoperability, and also enables high level reasoning for conflict resolution and policy adaptation. We describe our policy based network that uses packet content semantics to best handle different streams, and show how our framework can be used to secure enterprise networks and the BGP routing process.

Utilizing semantic policies for managing BGP route dissemination

Policies in BGP are implemented as routing configurations that determine how route information is shared among neighbors to control traffic flows across networks. This process is generally template driven, device centric, limited in its expressibility, time consuming and error prone which can lead to configurations where policies are violated or there are unintended consequences that are difficult to detect and resolve. In this paper, we propose an alternate mechanism for policy based networking that relies on using additional semantic information associated with routes expressed in an OWL ontology. Policies are expressed using SWRL to provide fine-grained control where by the routers can reason over their routes and determine how they need to be exchanged. In this paper, we focus on security related BGP policies and show how our framework can be used in implementing them. Additional contextual information such as affiliations and route restrictions are incorporated into our policy specifications which can then be reasoned over to infer the correct configurations that need to be applied, resulting in a process which is easy to deploy, manage and verify for consistency.

Using peer-to-peer data routing for infrastructure-based wireless networks

A mobile ad-hoc network is an autonomous system of mobile routers that are self-organizing and completely decentralized with no requirements for dedicated infrastructure support. Wireless infrastructure in terms of base stations is often available in many popular areas offering highspeed data connectivity to a wired network. In this paper we describe an approach where infrastructure components utilize passing by mobile nodes to route data to other devices that are out of range. In our scheme, base stations track user mobility and determine data usage patterns of users as they pass by. Based on this, base stations predict the future data needs for a passing mobile device. These base stations then collaborate (over the wired network) to identify other mobile devices with spare capacity whose routes intersect that of a needy device and use these carriers to transport the needed data. When such a carrier meets a needy device, they form ad hoc peer-to-peer communities to transfer this data. In this paper, we describe the motivation behind our approach and the different component interactions. We present the results of simulation work that we have done to validate the viability of our approach. We also describe, Numi, our framework for supporting collaborative infrastructure and ad hoc computing along with a sample application built on top of this highlighting the benefits of our proposed approach.

Using location information for scheduling in 802.15.3 MAC

In recent years, UWB has received much attention as a suitable physical layer (PHY) for wireless personal area networks (WPANS). UWB allows for low cost, low power, high bandwidth, short reach communication well suited for personal operating spaces. One of the key features offered by UWB is very accurate ranging between a transmitter/receiver pair. The IEEE 802.15.3 is a MAC protocol that has been proposed for WPANs. In this MAC, a combination of CSMA/CA and TDMA is used to achieve channel scheduling. The TDMA component ensures only one transmitter/receiver pair within a piconet is active at any given time thereby ensuring an exclusion region that covers the whole piconet. In this paper, we propose a less stringent scheduling mechanism that allows for concurrent communication between UWB transmitter/receiver pairs within a piconet. Exclusion is necessary only when the communicating entities are close enough such that interference between them would adversely affect successful reception of data at the receivers. The piconet coordinator (PNC) uses the ranging information provided by UWB to accurately position transmitters and receivers. The PNC schedules parallel transmissions between distinct transmit/receive pairs as long as they do not interfere. We present the results of our simulations of our proposed modifications and show that the network throughput can be significantly increased with very little change to the 802.15.3 MAC.

ATM network connection management using mobile agents

Configuration management is an integral part of the network management effort. ATM network configuration management must support the creation, modification, and termination of virtual path and channel connections, provide ILMI support for neighboring nodes, and support interface and buffer management for intermediate systems. Currently, permanent virtual circuits (PVCs) are established manually by creating a permanent virtual path link to form the desired connection. As ATM networks grow in size, configuration management must implement an intelligent approach for creating, re-configuring, and destroying permanent virtual circuits. This paper presents a mobile agent based connection management scheme for establishment and teardown of PVCs in an ATM network.

ATM network discovery using mobile agents

With the proliferation of new networking technologies, and the demand for new services, it will become increasingly difficult, and nearly impossible, to manage large-scale networks without an intelligent, automated management system. Discovering and keeping track of the topology of a network is essential for effective network management. We introduce a distributed algorithm for discovering the connectivity graph of an ATM network using intelligent mobile agents. In the proposed scheme links are discovered in a distributed fashion, thereby making this approach significantly more scaleable than applications using the traditional client/server model and SNMP.