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Honestly Mate, SUS will save your bandwidth!

The following story was submitted on the condition that all the people involved in it retained their anonymity. If you’d like to submit your own story, drop a line to [email protected]


As for the story itself:


What I can tell you is that a highly salaried consultant had been in negotiations with a client that had several hundred Windows XP Professional computers at a suburban office location. With the recent publicity surrounding service pack 2, the client had approached the consultant asking how these several hundred Windows XP Professional computers could be kept up to date with Microsoft’s patches. The current scheme at the client’s company involved updates being haphazardly downloaded over the client’s ISDN connection and randomly applied as people saw fit.


Given the Windows only environment, the consultant recommended that Software Update Services (SUS, now WSUS: Windows Software Update Services) be implemented. For those not in the know, SUS allows a single server on the network to host all updates, service packs and hotfixes. Rather than download each update individually from the Microsoft Windows Update servers on the Internet, Windows XP computers can download the update directly from the SUS server. The consultant told the client that this would save them a significant amount of bandwidth compared to the existing scheme. The client liked the idea, and SUS was implemented.


When you set up a SUS server for the first time, you need to download the existing patch database. The patch database is a collection of all of the patches currently available. The patch database is a bit over 2 gigabytes in size. The consultant did a back of the envelope calculation and figured that with an ISDN link at the client’s site, the download would complete overnight. Given that his own office had a similar link, there was no real advantage in doing the download off-site.


When he arrived at the client’s site, the consultant began the download of the patch database. Once he confirmed that it was all working, he told the client it should be finished by the next morning and asked the client to call him if any problems arose.


Two days later the consultant got a call. The client was concerned that the patch database still hadn’t finished downloading. There had been complaints from users. Far from saving the company’s bandwidth, email was working at a snail’s pace and no-one had been able to browse the web for the last 48 hours.


This confused the consultant. He asked the client if he was sure that they did have an ISDN link as he had been originally informed. The contact replied that he was certain, but just to double check, he would find the company’s most recent ISP bill.


After a few minutes digging around in filing cabinets, the client came back on the phone and said “Yes, it is ISDN all right. Says right here on the invoice that we have an ISDN BRI connection!”




ISDN comes in several flavors.


ISDN BRI        128 Kbps.

ISDN PRI        1.544 Mbps


Assuming a 50% overhead, it would take you about 4 hours and 20 minutes to download 2 gigabytes over an ISDN PRI link. With the same overhead, it would take you 52 hours to download the same amount of data over ISDN BRI. Figures thanks to


Microsoft is hosting a chat on WSUS on the 8th of June at 12pm EDT to coincide with the Windows IT Pro magazine cover story on the product. Click here for more information

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