Technical Reports

Thesis Papers

Authors Featured on this Page:

J.S. Baras

M. Liu

Papers resulting from CSHCN-related research are periodically added to the Institute for Systems Research Technical Report Database where they can be browsed by year or searched by author or keywords.

Hierarchical Modeling for Network Performance Evaluation (CSHCN TR 2000-8) by Mingyan Liu, John S. Baras

In this paper we present a hierarchical network model to estimate the connection blocking for large hierarchical networks.

As networks grow in size, nodes tend to form clusters geographically and hierarchical routing schemes are more commonly used, and it is important that network modeling methods have scale-up capabilities. Loss networks and reduced load/fixed point models are often used to approximate call blocking probabilities and hence throughput in a circuit switched network. We use the same idea for estimating connection blocking in a data network with certain QoS routing schemes. However so far most work being done in this area is for flat networks with flat routing schemes.

We aim at developing a more efficient approximation method for networks that have a natural hierarchy and/or when some form of hierarchical routing policy is used. We present hierarchical models in detail for fixed hierarchical routing and dynamic hierarchical routing policies, respectively, via the notion of network abstraction, route segmentation, traffic segregation and aggregation. Computation is done separately within each cluster (local) and among clusters (global), and the fixed point is obtained by iteration between local and global computations. We present results from both numerical experiments and discrete event simulations.

Hierarchical Loss Network Model for Performance Evaluation (CSHCN TR 2000-1) by Mingyan Liu, John S. Baras

In this paper we present a hierarchical loss network model for estimating the end-to-end blocking probabilities for large networks.

As networks grow in size, nodes tend to form clusters geographically and hierarchical routing schemes are more commonly used. Loss network and reduced load models are often used to approximate end-to-end call blocking probabilities, and hence, throughput. However so far all work being done in this area is for flat networks with flat routing schemes.

We aim at developing a more efficient approximation method for networks that have a natural hierarchy and/or when some form of hierarchical routing policy is used. We present two hierarchical models in detail for fixed hierarchical routing and dynamic hierarchical routing policies, respectively, via the notion of network abstraction, route segmentation, traffic segregation and aggregation. Computation is done separately within each cluster (local) and among clusters (global), and the fixed point is obtained by iteration between local and global computations. We also present numerical results for the first case.

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