Browse Prior Art Database

ADJUSTABLE-RATE THROTTLING OF PARALLEL DOWNLOAD SESSIONS

IP.com Disclosure Number: IPCOM000009025D
Original Publication Date: 1999-Jan-01
Included in the Prior Art Database: 2002-Aug-01
Document File: 7 page(s) / 348K

Publishing Venue

Motorola

Related People

Richard Vanegeren: AUTHOR [+2]

Abstract

Reduction of scheduled base station outage per the "Five 9's" initiative is a powerful mandate for implementing a scheme to minimize the length of time required for the iDEN Access Controller Gateway (ACG) to conduct code download sessions with Base Radio Controllers (BRC). This applies to initial download (i.e. after a site reset) as well as 'hot' Base Radio (BR) installations when multiple BRs are added to a site that is currently in service. Downloading BRC code on an Ethernet LAN that is actively serving voice traffic, however, can cause audio degradation secondary to increased packet delivery delays. The potential for this problem exists mainly on those sites on which there is a large number of hosts (one ACG and many BRCs) sharing the LAN. For these site configurations, the rate at which download sessions deliver packets must be controlled to ensure the availability of adequate LAN resources for timely delivery of voice packets. For smaller site configurations it is desirable to per- form code download at the fastest possible rate to minimize outage time. By dynamically adjusting the download rate according to the number of Table 1: Download time estimates registered BRs at the site, it is possible to minimize outage by conducting download sessions with all newly added BRs while ~simultaneously guarantee- ing an acceptable level of quality for end-user ser- vices.

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MO-LA Technical Developments

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ADJUSTABLE-RATE THROTTLING OF PARALLEL DOWNLOAD SESSIONS

by Richard Vanegeren and Anatoly Agulnik

INTRODUCTION

  Reduction of scheduled base station outage per the "Five 9's" initiative is a powerful mandate for implementing a scheme to minimize the length of time required for the iDEN Access Controller Gateway (ACG) to conduct code download sessions with Base Radio Controllers (BRC). This applies to initial download (i.e. after a site reset) as well as 'hot' Base Radio (BR) installations when multiple BRs are added to a site that is currently in service. Downloading BRC code on an Ethernet LAN that is actively serving voice traffic, however, can cause audio degradation secondary to increased packet delivery delays. The potential for this problem exists mainly on those sites on which there is a large number of hosts (one ACG and many BRCs) sharing the LAN. For these site configurations, the rate at which download sessions deliver packets must be controlled to ensure the availability of adequate LAN resources for timely delivery of voice packets. For smaller site configurations it is desirable to per- form code download at the fastest possible rate to minimize outage time. By dynamically adjusting the download rate according to the number of

Table 1: Download time estimates

registered BRs at the site, it is possible to minimize outage by conducting download sessions with all newly added BRs while ~simultaneously guarantee- ing an acceptable level of quality for end-user ser- vices.

  The code download ;protocol is a variation of TFTP which uses a stop-and-wait scheme to provide flow control.

ALTERNATIVE APPROACHES FOR CODE DOWNLOAD

  Table 1 lists code download time estimates for the various approaches. The numbers are based on a total of approximately 5,340 TFTP data packets for executable download and configuration, minimum of 2.4 ms of BRC processing delay and 4OOps of ACG processing delay', and the assumption that time lost to collision and resolution is insignificant compared to the total code and configuration down- load time (analysis of expected collision resolution characteristics calls this assumption into question).

I

Download time (minutes)

1BRs 12BRs 124BR.s

Download Approach

0 Mororola, 1°C. ,999 216 Janualy 1999

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0 M MO-LA

Technical Developments

CONTROLLED SEQUENTIAL DOWNLOAD

  The ACG's download session with a BRC can be limited to a rate which ensures that resources are always available for other ACG-BRC interaction. Given a constant inter-packet interval (IPI) of 10 ms and a code size requiring 5343 data packets, the total download time is given by the following expression:

T=[( IO ms/pkt)(5343pkrs)+l5s]xN=68,4sxN

  Where T represents the total download time and N is the number of BRs at a site. The number of pack- ets is based on the current BRC software release and includes 15 seconds of delay between code and config- urat...