Applying Queueing Theory to Network Design

We think of waiting lines as the circumstance we encounter at the grocery store but in the telecommunications world lines can also form for packets waiting to be handled by routers or telephone calls waiting for a trunk to become available. This newsletter will describe how to use queuing theory as a tool to predict and analyze several telecommunications situations using one simple formula that has many, easy to apply, capabilities.

A Simple Network Throughput Model

The network design function typically involves such activities as planning the physical connectivity, determining the performance and capability of the network, sizing the links and nodes, and calculating installation and operational costs. Some of these tasks are straight forward and some, such as performance determination and link sizing, involve mysterious calculations and guess-work. This newsletter will show you a concrete approach to network performance determination and describe a simple throughput estimation model that can be used to solve such problems.

Understanding Network Availability

Availability means uptime and we like uptime; however, what does uptime really mean? We like the idea of fault tolerant systems and five-nines (99.999%) availability, but how hard is that to achieve and what does it cost? This newsletter will provide you with the tools needed to truly understand network availability by describing some of the fundamental mathematics and simple probability theory concepts that are at the core of being able to determine answers to such questions for a networking ennvironment.

Calculating VOIP Bandwidth

Calculating trunk requirements in the voice world meant determining the call load during the peak hour and using Erlang formulas to derive the appropriate number of trunks for a given blockage factor. In the VOIP world, the total bandwidth required to handle peak hour calling across the IP network must be determined. This newsletter describes a calculation process that can be used to estimate the data network bandwidth required per VOIP call and for the total system plus a review of the Erlang model.

SIP Server Capacity Planning - An Introduction

Session Initiation Protocol (SIP) is a telecommunications signaling protocol for establishing, maintaining and tearing down sessions between a variety of types of real time media – voice, video, text messaging, and on-line gaming. This newsletter will highlight important issues, considerations, metrics and calculations that would support the process of determining the capacity of SIP proxy servers, which are used to assist the session establishment process. We are going to discuss capacity planning in terms of IP telephony applications, with an emphasis on end-user-office-level SIP servers – the PBX replacement engine.

IP Telephony Request For Proposal (RFP) Template

The following list containing 11 sections was created for use as a template for the development of an RFP for IP telephony based systems, including a provision for a contact center project. An effective RFP should include a description of the project's time tables and plans, how vendors should respond, a complete and detailed statement of anything financial, a detailed description of the proposed system's structure and how it would be safeguarded, technical descriptions of the required voice and contact center's capabilities, a solid definition of how the proposed system would interact with other software products, the features and capabilities of the end user's IP phone and desktop computer related functions, a thorough discussion of the capabilities of a hosted system if proposed, and extensive information about how the new system will be run and managed.