Browse Prior Art Database

Load Balancing for Variable Sized Connections with Dynamically Changing Bandwidth Requirements

IP.com Disclosure Number: IPCOM000110120D
Original Publication Date: 1992-Oct-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 4 page(s) / 203K

Publishing Venue

IBM

Related People

Herkersdorf, A: AUTHOR [+2]

Abstract

Load balancing in packet switched communication networks is required at different abstraction levels. Within the scope of large-scale networks, it is desirable to distribute various connections over multiple paths between a pair of network nodes. The long term goal is to prevent an early saturation on some paths and to maximize network throughput under a given packet loss probability but also to minimize end-to-end delay of the connections [1,2]. Within the scope of a network node, it is desirable or even necessary to perform load balancing for various connections between a specific input-output pair in order to prevent internal blocking or congestion (3). The terms link, route, and path can be used interchangeably throughout this article.

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Load Balancing for Variable Sized Connections with Dynamically Changing Bandwidth Requirements

       Load balancing in packet switched communication networks
is required at different abstraction levels.  Within the scope of
large-scale networks, it is desirable to distribute various
connections over multiple paths between a pair of network nodes.  The
long term goal is to prevent an early saturation on some paths and to
maximize network throughput under a given packet loss probability but
also to minimize end-to-end delay of the connections [1,2].  Within
the scope of a network node, it is desirable or even necessary to
perform load balancing for various connections between a specific
input-output pair in order to prevent internal blocking or congestion
(3).  The terms link, route, and path can be used interchangeably
throughout this article.

      The traffic in a future broadband integrated services digital
network (B-ISDN) can only be estimated and, hence, only vaguely
modelled.  However, the following general trends can be identified:
Due to the large number of different applications (i.e., voice, data,
and video), connections with different and widely diverging bandwidth
requirements will have to be supported (3,4).  Because several end
user applications can dynamically be multiplexed onto a common
virtual channel (4,5) or network connection (2), the bandwidth
requirement of a connection will not be constant during its lifetime
but may vary by multiples of its initial value.

      A summary of basic algorithms for load balancing within ATM
(Asynchronous Transfer Mode) switch fabrics can be found in (3).  An
overview of path selection at the network level is given in (1,2).
However, none of these approaches considers bandwidth variations of a
connection as criterion for path selection.

      The motivation to extend present load balancing or path
selection algorithms arose from the demand to support both variable
but fixed sized connections as well as connections with dynamically
changing bandwidth requirements.  The intention is to propose a
uniform mechanism that achieves an optimized load balancing among
multiple links forconnections with said characteristics.

      A performance comparison of several path hunting (load
balancing) strategies applied to different switch fabric topologies
is presented in (3).  It is shown that the optimum hunting strategy
strongly depends on the traffic mix considered.  In an ATM
environment, where different traffic classes with varying bandwidth
requirements are supported, the sequential hunting algorithm with
homing provides the best performance in terms of blocking
probability.  However, the study in (3) did not consider that already
established connections need to have the possibility to increase
their bandwidth during lifetime.

      A new algorithm is proposed here which incorporates the
advantages of the basic load distribution algorithms (described in
(3...