The old rules no longer seem to apply for cable operators. Instead of being judged on EBITDA (Earnings Before Interest, Taxes, Depreciation and Amortization), Wall Street seems more inclined these days to measure MSOs based on free cash flow. That means cable operators have to keep their expenses in check, especially those tied to building network infrastructure and network operating costs.

Because of this changing landscape, cable MSOs are being pressed to take a closer look at how bandwidth management techniques can help them curb capital expenses and, at the same time, squeeze more dollars out of their existing networks.

To do that, operators must sharpen the vision they have into their networks and better understand what their high-speed data (HSD) customers are doing on the network, and what it costs from a connectivity viewpoint to support each one.

"Until now, MSOs were flying blind [regarding] how their pipes were being used," especially with traffic at the interface level, says Jason Schnitzer, chief technology officer and co-founder of Stargus Inc.

Cable's real business for high-speed data, he adds, is knowing what each user is consuming, and understanding if that user's consumption is consistent with the design and economic goals for the network.

Narus' software [click to enlarge]
Figure 1: As shown in this sample, Narus’ software probe and subsequent datacollection applications are chewing up the most bandwidth, and help operators analyze what potential actions to take.
[click here to enlarge]
The absence of that visibility can present a bottom-line problem if a small number of customers are devouring a hefty chunk of the bandwidth and the existing capacity wells are filling up with traffic. That's because the economics call for more and more network equipment and additional long-haul networking costs.

Generally, there are two schools of thought for bandwidth management: those who want to know, at an infinitesimal level, what kinds of applications are consuming what percentage of the bandwidth; and those who only want to know how much bandwidth is being consumed and place limits on how much can be consumed each month.

Which school of thought an operator decides to take will depend on whether "I really want to be in the business of caring about what kind of data people are sending, or if I want to be concerned more with the volume that they're sending," says Jay Rolls, vice president of data engineering, Cox Communications Inc.

Regardless of school, cable operators are coming to grips with the fact that new trends among high-speed data customers are causing them to take a fresh look at enhanced or completely new bandwidth management schemes.

For starters, there's the so-called "bandwidth hog."

"The need [for bandwidth management] is driven by the fact that you have a small number of subscribers using a disproportionate amount of the resources, plain and simple," says Rolls. "Near-term, long-term– that's always going to drive the need."

"MSOs are seeing today a lot of abuse in the network, not in the form of maliciousness, but in using the service in a way it's not designed to be used," agrees Milind Gadekar, vice president of marketing at Sunnyvale, Calif.-based bandwidth management company P-Cube Inc.

P-Cube's programmable hardware
P-Cube’s programmable hardware can become “aware”
of emerging Internet applications.
Peer-to-peer applications represent a more specific example of an application that can cause bandwidth problems for cable operators, as users can continue to download and upload massive chunks of data, even when the computer is unattended. Such applications can severely tax the upstream path, causing the need for a more symmetrical data pipe and advanced specifications such as DOCSIS 2.0.

What was once used primarily as a lithe path for keystrokes and mouse clicks has suddenly been asked to accommodate massive media files and support QoS-sensitive multi-player "twitch" gaming applications.

Back in 1999, "we saw very asymmetrical requests, and upstream commands were very minimal," with a down/up ratio of about 7-to-1, says Don Loheide, vice president of engineering and technology at Charter Communications Inc. These days, that ratio is down to about 3-to-1, he adds.

In addition to high bandwidth users and a taxed upstream path, cable operators must also be wary of consumers who "uncap" their cable modems by injecting a bogus configuration file that eradicates the capacity limits put in place by the cable operator. If the wayward file is accepted by the modem, the user can enjoy higher download speeds and absorb network resources without paying for a higher tier of service.

Adding vision and intelligence to the network is a markedly different way for operators to approach those problems than they did in the early days of HSD.

Excite@Home Corp., before succumbing to bankruptcy in October 2001, "was throwing bandwidth at the problem, and costs were out of control," says Gadekar, a former Excite@Home executive. "But [at the time], we didn't have visibility at that granular level. A few years ago we had to have people go through router logs and news server logs to identify 10 to 20 customers. It was killing us from a cost standpoint."

The case today is markedly different, as MSOs now have access to software and hardware platforms designed to see exactly what their subscribers are doing–without all of the expensive elbow grease.

Tools of the trade

Tiering is just one weapon cable operators are using today to satiate the appetite of (and get a better return on) high bandwidth consumers. Cox presently offers tiered levels of HSD service in Las Vegas, and is conducting a limited market trial in New England. Charter, meanwhile, offers tiered services in most of its systems, charging about $60 per month for its gold-level service. AT&T Broadband is also offering a 3 Mbps "UltraLink" service in select markets for between $79.99 and $82.99 per month.

Straight tiering, however, is "like using a hacksaw when you require a fine scalpel," Gadekar says, arguing that consumers won't go for the higher tiers unless there's a perceived value in doing so.

"Today, I have an unlimited fast pipe, so there is no reason for me to upgrade to a higher service," he adds. "But if my VPN slows down tomorrow, I definitely will pay $5 to $10 per month more to get that higher speed." A network with more bandwidth intelligence will know who those potential targets are, he says.

Many operators are already wielding tools designed to sharpen their visibility into the network. Charter, like many other MSOs that leverage DOCSIS, is using Simple Network Management Protocol (SNMP), but also employs a Web-based SNMP manager developed by Tulsa, Okla.-based SolarWinds.

The SolarWinds platform enables Charter to set up a collection server in the master headend to check bandwidth utilization and to monitor upstream and downstream ports.

"It will actually go out and query our CMTSs and our backbone routers and our network to provide us with deep bandwidth utilization across each of the ports," Loheide says.

Although SolarWinds comes with built-in DOCSIS support and automated feature sets, there are freeware and shareware bandwidth management products available on the Internet. What's Up Gold is a shareware product that helps operators monitor their entire network. MRTG (Multi Router Traffic Grapher) is a freeware tool that monitors the traffic load on network links, and generates HTML pages that display live network traffic conditions.

Still, Loheide acknowledges that a product like SolarWinds doesn't tell the whole bandwidth story. "It really doesn't tell us what [subscribers] are doing," he says. "It's just telling us how many bytes they consumed in a day. It doesn't say if it was three sessions, or one session that lasted four hours, or the average bit rate per session."

Peering deeper

With the number of companies specializing in bandwidth management products and services continuing to grow, cable operators don't have to look too far to find one that might suit their needs.

Stargus, for example, helps cable operators understand where they are experiencing HSD service degradation and provides recommendations about what to do about it through a broadband network surveillance and control platform called CableEdge. Using standard network management protocols, CableEdge can determine how much bandwidth each user on the network is consuming.

Stargus' first application, Optimizer, provides visibility into a DOCSIS 1.0 environment. Further down the road, Stargus plans to introduce applications that track subscriber and multiple ISP usage, analyze IP telephony traffic patterns and configure and manage home networking services. Presently, Stargus' Optimizer product is involved in two trials with top 10 MSOs, managing an aggregate 400,000 cable modems.

Palo Alto, Calif.-based Narus Inc. markets a software probe application that generates network information in real time. That software can reside near the CMTS or between CMTSs, depending on what the cable operator wants to see. "We take that data...and feed it to various back office applications," says Narus Director of Marketing Ted Hunting.

Drilling down to the application level, Narus' software can tell an operator how many customers are placing an IP telephony call or streaming content over the Internet. In addition to hunting down HSD abusers, that level of detail can help operators create new services and bill for them, Hunting says.

Narus claims that it can boost an operator's overall HSD business practice by going after existing dial-up subs by creating a "middle market" tier that doesn't cut into an operator's gross margins. Narus does this by placing bandwidth consumption thresholds or application limitations on subscribers, and then tracking how much they use during the month. From there, an operator can see that information, generate reports and then bill based on that information.

P-Cube is also going after the broadband sector with a programmable "service control" hardware/software combination that can see into the subscriber and application level.

CableEdge graph [click to enlarge]
Figure 2: This CableEdge graph from Stargus shows the upstream and downstream usage during a week
for the top 25 subscribers on a
given cable system.
[click here to enlarge]
Because P-Cube's box is programmable, it can stay in lock step with the ever-changing landscape of Internet applications, Gadekar says. KaZaA and Morpheus, for example, are extremely popular file sharing programs these days, but other flavors might emerge week-to-week or month-to-month. "As applications change, the [P-Cube] box can become aware of them," Gadekar adds. For now, P-Cube does that programming, but the company eventually would like to provide toolkits that allow MSOs to do it themselves.

In addition to becoming aware of new applications, P-Cube's hardware can also enforce acceptable use policies set by the operator for different tiers of service. A basic service, for example, might provide all-you-can-eat e-mail and Web browsing, but could limit or block access to bandwidth-intensive UseNet and peering applications. Likewise, a more expensive tier could do just the opposite.

ChanneLogics, a bandwidth management company based in Atlanta, markets software designed to monitor bandwidth usage every few minutes and throttle it up or down based on a policy engine and proprietary algorithms.

The company's CableLogics platform takes a higher macro level view and does not tap directly into the data path. CableLogics, which runs on a 1-U high rack-mountable server, hooks into the CMTS level of the network, but can go to the modem level as well.

Though ChanneLogics can forecast bandwidth requirements in two-to-three minute intervals, those tools can also extrapolate months and weeks ahead, says company Vice President of Marketing Bill Carlson. Having that visibility could also help operators expose high bandwidth users and target them for more profitable tiers of service, or at least ensure that their bandwidth consumption levels better match what they're paying each month.

Empowering the customer

Though many bandwidth management products and methods give operators more control and vision into their networks, still others are designed to give more control to the high-speed customer.

Efficient Networks, a division of Siemens AG, is developing a Web-based tool for cable operators that high-speed data customers use to ratchet their bandwidth up or down. A subscriber, for instance, could crank up the bandwidth for Internet VOD content, or to download a massive document–all without contacting the service provider directly.

Efficient's middleware, which talks to the device elements on the network, is also designed to interface with an operator's order entry and billing system, says Chad Leedy, product manager for Efficient's service management business unit.

Privacy issues

Keeping a closer eye on subscriber activities can also create an easy target for privacy advocates.

After it transitioned off the old Excite@Home network, Comcast Corp. came under fire early this year for monitoring HSD subscriber activities and collecting personal information from customers without prior consent. Comcast quickly discontinued collecting that information, and assured users that it never had or will share that information with outside parties, except as required by law, and reviews information to manage the performance of its networks. Despite those assurances, the MSO became the subject of a class-action lawsuit in May regarding the practice.

Narus' Hunter agrees that cable operators that collect information as part of their efforts to boost network efficiency and capabilities will have to deal with perception problems rightly and wrongly tied to privacy issues. They'll have to help customers understand that Big Brother isn't lurking on the other side of their cable modems.

"Yes, we see every packet that passes by, and at the edge we get rid of some information," Hunter says. "We don't collect the file itself. We don't know what's in an e-mail, for example. We throw out that information."

Instead, Narus collects data to drive the business side of the equation, Hunter adds. Instead of the content of a specific e-mail, Narus' software can discern how many e-mail messages were sent.

Considering the privacy travails Comcast has faced, "the safest avenue is to look at a subscriber's bandwidth . . . and go through SNMP versus the stateful inspection of packets," says Carlson.