Do you have the means to ensure critical traffic gets through while less important--and often expensive--traffic is curtailed? Find out what packet shaping can mean to the bottom line of your organisation.
Packet shaping "is a hot topic these days," says Roland Chia, national business manager at Dimension Data Australia. Organisations are paying more attention to application performance and response times, and are realising that a lack of communication between application developers and network teams prior to implementation means the bandwidth requirement for new projects receives insufficient attention.
Beware that "packet shaping" generally refers for one of two things. In the world inhabited by carriers and suppliers, shaping simply means that the flow of packets is kept within a maximum rate, and the excess data is left in a queue or--in extreme cases--dropped. In the context of IP networking, it is implicit that shaping is preceded by packet classification and queuing, with some classes of data being given priority over others.
Some carriers offer data services that include packet shaping in the IP sense, says Anthony Buckton, solutions architect at Nortel, but "it might be smarter for customers to do the packet shaping themselves".
Carrier-style shaping can work for general IP data traffic, but shaping Voice over IP (VoIP) and other time-critical data delays the packets unless classification and queuing is done as well. Otherwise, "shaping on its own can cause more problems," he says.
One example of a carrier service that offers IP-style shaping is TPIPS (Telstra Private IP Service), which uses Nortel's Passport switches with software for classification, queuing, and shaping.
"Traffic management in the LAN will soon take serious shape" because of the emergence of VoIP and desktop videoconferencing, says David Gabo, senior consultant at NCR Worldwide Customer Services. IP telephony needs regulated bandwidth in the LAN, but "I'm sceptical about packet shapers" in this context, he says, suggesting that control needs to be embedded in the infrastructure.
Dave Côté, president and CEO of Packeteer, says the only option other than packet shaping is adding more bandwidth. Five years ago, the expectation was that bandwidth would become effectively free, but in the last couple of years the IT community has realised that isn't going to happen. "The market is heading towards us," he says. "There really isn't anybody who uses the control technology we do."
That may be true, but Packeteer does not have the market to itself. South Australia's Foursticks uses its patented "NP" technology combining queuing algorithms and Quality of Service (QoS) consistency checking in software that can be embedded in applications, devices, and operating systems.
The use of third-party hardware saves money and allows customers to leverage their existing relationships with suppliers, says the company's chief technology officer Alan Noble. This also means hardware can be selected according to customer needs, such as highly available Sun configurations or inexpensive generic Intel-based PCs. "It's more like ‘Foursticks NP inside'," he says.
Foursticks' patent-pending algorithms provide more accurate and more efficient management of interactive and real-time applications without hard reservations, Noble says, providing better application stability and more efficient use of the network. The software is independent of line speed (both in terms of capability and pricing), and can manage burstable bandwidth in frame relay networks, taking advantage of available bandwidth above the committed rate.
"The cost of implementing Foursticks NP is typically returned within six to 12 months," says Noble. "For example, Bridgestone reports an immediate saving of $100,000 in bandwidth costs." Bridgestone uses TPIPS to link approximately 80 sites around Australia, but was experiencing network congestion problems that slowed critical ERP applications including SAP.
"Network performance was very variable," says Darren Denley, Corporate Manager Information Systems, Bridgestone Australia. "People eventually decided they didn't want to use the system as it was too slow."
The implementation of Foursticks NP on five of the company's links identified unnecessary and inappropriate traffic, and "we were able to allocate bandwidth usage to the applications that are bringing most value to our business," he says.
"Setting policies to control network usage is easy using NP and we've noticed an instant improvement in the performance of SAP across the WAN," says Denley. "Response times are now consistent and predictable. The product itself addresses fundamental areas of IT management which are becoming more and more critical to ensuring that the quality of IT solutions exceed customer expectation."
Foursticks NP has also been added to Singapore-based infrastructure management solution provider Equator One's MAX network management suite. Wilfred Wong, chief executive and chief technology officer, says "Foursticks has developed a superior network performance algorithm and policy-based QoS, but importantly, it is an open system, which allows us to integrate NP software into the current and next generation performance controls in our MAX product suite."
Apart from enterprise sales and distribution and licensing arrangements, Foursticks has also embedded its technology into the Sun LX server, and into a Chinese-made router with a view to signing an OEM licensing agreement with a Hong Kong network equipment manufacturer.
Driving Forces
Mike Morford, senior technologist at Packeteer, sees three trends that are driving organisations towards packet shaping.
First, there are more and more applications--VoIP, video, Web conferencing, CRM, etc--using corporate networks, but bandwidth over the last mile is still limited to around 2Mbps. Consequently, that bandwidth must be managed.
Secondly, "the network industry is growing up in a business sense," and we need to apply classical management techniques to the network, just like any other resource. So processes should be consistent, measurable, and repeatable.
Thirdly, there is a shift in focus concerning application availability. Instead of asking whether a server or application is up, the question is becoming "is it highly usable?" A significant contributor to usability is the amount of competing network traffic.
Morford speaks of network congestion events--bursts of traffic that saturate a link. They can have various causes, including someone downloading a large service pack during the day (that can be enough to make other applications unusable for 20 minutes to an hour), or people watching streaming video from news sites during major events such as the war in Iraq. That's bad enough if only one person is doing it, but five users can fill a 1Mbps link, he says. Instant Messenger might be a legitimate application, but it allows file transfers and if someone sends or receives a 700MB movie file, that's going to affect your network. Even viruses and worms can be a problem: SQL Slammer would use all available bandwidth looking for servers to infect, he says. According to Morford, network managers say "these little insidious problems really make my network unusable." Each application needs to be given enough bandwidth to do its job, but there must also be an upper limit so it doesn't take up all the available bandwidth.
Frame relay prices are now rising in the US, he says, and so "people are recognising that for the foreseeable future it [bandwidth] will be a constrained resource." Organisations want to use new applications--videoconferencing can make a business more efficient--but the bandwidth must be found for them. To make things worse, some applications are designed for LAN use, where Gigabit Ethernet is now commonplace. WAN links are lower capacity, and "people aren't buying infinite amounts of bandwidth," he says.
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Peter Owen, territory manager--Australia and New Zealand at Packeteer says that a difference between Australia and the North Island of New Zealand is that broadband is virtually everywhere in the latter, and E1 (2M) links are cheap. Despite (or maybe because of) this, New Zealand is a big market for Packeteer. People need to manage the traffic flowing across the links, even if it's just Citrix data, he says.
A PacketShaper can be useful when connecting small (even one- or two-person) remote offices to a central site using ADSL, as only one device is needed. "We're seeing a lot of sales in 2003 in that marketplace," he says. Morford adds that part of the reason is that even if you start with a relatively low capacity link, upgrading to the next level is generally expensive, so investing in one PacketShaper can save having to pay for fatter pipes to several offices. But if there is only one remote site, one or two people are unlikely to generate enough traffic to cause contention.
Taking advantage
Packet shaper deployment is typically a three-step process, says Morford. First, the device provides application visibility, allowing the network manager to see what's really happening on the network. Communication between different areas of responsibility within IT may suffer during rapid deployments.
Visibility is quickly followed by the second stage, which is applications control. That involves making business decisions about the policies that will be applied to different applications.
The third stage is network optimisation. Packeteer recently introduced a compression add-on for the PacketShaper that can reduce the bandwidth needed by some applications. It is important that classification is performed before compression, because an attempt to compress already-compressed data will not give any benefit but it will add latency, which is undesirable in time-critical applications such as IP telephony.
If classification and compression are done separately, "they [reduce] each other's value to the network," says Owen. Doing them together also means that flow control can be based on the amount of data before compression, he adds.
To get value from packet shaping, it is essential that business rules can be quickly and easily mapped onto device settings. To support the packet-shaping capabilities of its devices for the non-carrier market, Nortel offers methodologies to help end-users implement and manage these rules. Users can point and click to set priorities, "mapping their business-important applications into the network," says Buckton.
Organisations using Nortel products in this way include Deloitte Touche Tohmatsu, State Rail (NSW), and CeNTIE (Centre for Networking Technologies for the Information Economy).
CeNTIE recently ran a trial of a 10Gbps Ethernet link involving the use of haptics (simulated touch) to manipulate an object at a remote location. As part of the demonstration, data from AARNET was transmitted simultaneously with the virtual environment information so that the link was running at full capacity. The appropriate prioritisation of packets meant the haptics were unaffected by the other traffic, despite the 100 percent utilisation, says Buckton.
Nortel equipment is also being used in the NSW Department of Education network to classify users (eg, primary/secondary/TAFE and teacher/student). "Being able to identify the user prior to shaping is important," says Buckton. "The difference [of doing it in the network] is we can tie it back to central management." Traffic classification can be in terms of socket numbers, IP addresses, or URLs, he says. The latter takes care of hosted applications where you don't necessarily know the IP address of the server, as the provider may redeploy your application from one box to another.
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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.