Case study: ROI in Victoria
The Victorian Department of Sustainability and Environment has a converged WAN carrying data, VoIP and videoconferencing data to its 34 offices around the state.
Packeteer PacketShapers are used to deliver quality of service by prioritising corporate applications appropriately. Apart from voice and video, the network carries traffic from Oracle Financials, SAP (human relations system), Lotus Notes, and software used in fire suppression. "We've seen some pretty incredible statistics," says senior technical manager Andrew Paynter.
When the remote sites were connected via 128K links, response times for individual transactions in Oracle Financials were around 30 or 40 seconds, which meant a complete operation such as entering a purchase order or processing goods received took around three-quarters of an hour. Specialists such as research scientists or fisheries enforcement officers notionally performed this work, but "these people don't have the time to sit for 40 to 50 minutes to buy something for their business," says Paynter, Consequently, they were hiring contract workers to deal with administrative tasks.
Upgrading the WAN links to 2 or 4M as part of the converged network project improved transaction times to around 15 seconds, but the new network architecture included PacketShapers and when they were activated this figure dropped to 3 or 4 seconds. "People can now transact in four or five minutes, as opposed to around 46 minutes," says Paynter, so DSE staff can find the time to perform these tasks themselves and the cost has fallen from around $30 to $3-$4 per transaction.
There have also been flow-on effects, such as a reduction in the re-polling of servers. Fault logging at the service desks has dropped dramatically, in some cases by 80 percent.
"If you increase the size of the link, it just gets taken up by more traffic... SAP agents [for example] take up whatever's there" says Paynter.
PacketShapers provide a granularity of control that can't be achieved if you implement QoS through routers, he says. DSE operates between 30 and 40 classes of service, and it is easy to adjust priorities as necessary. During last summer's major bushfires, Paynter could immediately increase the priority of the software relating to fire suppression as well as boosting the maximum bandwidth it was allowed to consume. This could not have been done so quickly through a routing platform, he says.
When videoconferencing was originally piloted by DSE, router and carrier-based tools were used to give the traffic sufficient priority, but that wasn't sufficiently dynamic as it reserved bandwidth even when there was no videoconferencing traffic. This is at odds with the idea of a converged network.
The WAN and LAN refresh that included the PacketShapers was carried out by Dimension Data between November 2002 and January 2003, and involved "107 mini-projects all running simultaneously," says Paynter. One PacketShaper is installed at each location, with redundant units at the network core to provide load balancing and fail over. If a remote PacketShaper fails, the network falls back to router-enforced queuing to prioritise video and voice traffic until a replacement can be delivered to the site and swapped in by the local staff.
"It's proved the value of applying business policies to the way you use your network," says Paynter. For example, the CFO can request a temporary increase in the priority of financials traffic during end of year processing, or during a disaster, fire crews can receive infrared images and real-time telemetry--"that's a fairly critical application in terms of time and the safety of staff involved in the suppression effort," he says. "Everything else went on the back burner."
According to Jef Graham, president and CEO of Peribit Networks, there are three kinds of people that are interested in their products: those who would rather not spend more on upgrading their broadband, those who can't get any more bandwidth, and those who want to downgrade their connection to improve the bottom line. When British American Tobacco in Australia was faced withi a new SAP rollout, it decided to go with Peribit Sequence Reducer products for the first reason. The SR-50 products that were selected have now been found to have increased existing BAT network capacity by 2.5 times, resulting in big savings (compared to purchasing larger WAN circuits)--savings that have provided BAT with an ROI of approximately four months.
Prior to installation, many of the BAT network links were already near capacity, and the deployment of SAP would have cause significant congestion and delay in the network. Using the SR-50s allowed BAT to stay within their existing 64Kbps link speed, even with the additional SAP traffic.
According to Gordon Anthony, CEO of Global Asset Systems in Australia (Peribit's distributor), "The BAT case shows how sequence reduction can be used to produce instant bandwidth to boost application performance."
The interesting thing about Peribit's sequence reduction technology is that it employs a totally new compression algorithm known as Molecular Sequence Reduction (MSR). MSR operates by finding variable-sized (not packet-sized) patterns anywhere in the data stream--these can be across multiple packets, applications, or sessions.
"Rolling out SAP is critical to our business," said Peter Deitz, Technology Manager at BAT. "International circuits are very expensive and critical to managing our widespread pan-Pacific operations. Peribit saves us over $4500 per month just on our links between Australia and New Guinea. The SR-50s are also very simple to operate--which is important because it minimises both my time involvement and travel. The decision only took us six weeks from start to finish--a very easy decision with a convincing ROI."
- "Packet Shaping in an IP Network implies classification and prioritisation (either through queuing or rate control), not merely capping the rate of flow.
- Packet shaping can ensure critical application traffic gets priority over less important or relatively time-insensitive flows.
- Packet shaping can be implemented by an appliance or added to the software in devices such as routers or servers.
- Packet shaping can be a useful adjunct to router-based QoS features for time-critical applications such as VoIP, delivering better results than either technology can in isolation.
- As a by-product of their primary function, packet shapers provide detailed insight into the traffic on a network.
- The more finely you want to classify traffic, the more appropriate a packet shaper becomes compared with router-based QoS.
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The HTB QoS mechanism under linux provides many of these capabilities. The only significant downside is that the documentation very poor at present.
Once you have it going and understand it well, it works wonderfully. I have it emplaced on our gateway here, and it makes an impressive difference in reducing the impact of some traffic types on our link responsiveness.
It's even more effective on my home firewall, where there are a lot of different traffic priorities, from ultra-bulk low priority traffic to VoIP and SSH data - all of which need to share the link at optimal performance.