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Application Layer Packet Classifier for Linux

L7-filter is a classifier for Linux's Netfilter that identifies packets based on application layer data. It can classify packets as HTTP, Jabber...

netfilter: del.icio.us/tag/netfilter

Why Fixing Internet Capacity Keeps the Telcos Honest

In the debate around Internet regulation and traffic, it’s important to understand the things that drive how much bandwidth we need. Without fixing the bandwidth shortage on the wire or in the protocols, we make it easy for carriers to claim that they need to regulate bandwidth in order to survive. If we can fix the bandwidth and efficiency problems, we take away one of the main reasons telcos claim they need to shape traffic and interfere with the Internet.To oversimplify somewhat, there are three basic ways to improve the Internet’s capacity:

Regulate traffic

Treat different traffic differently, according to its needs, through tiers of service. Technologies and protocols such as MPLS, RSVP, traffic shaping, queueing and so on can prioritize some applications or sites over others. Unfortunately, this is the zero-sum game that surrounds the Net Neutrality debate: My online video is better, but I can’t use search any more.

There are also significant consequences for users when companies employ some of these technologies. For example, throttling traffic by injecting TCP resets into the traffic stream can interrupt web sessions; similarly, dropping packets midstream messes with voice and video quality.

As a result, many service providers resort to “overlay” networks from content delivery networks (CDNs) like Akamai, BitGravity, and so on. Or they negotiate private peering arrangements. Either way, we’re already overcoming congestion with “premium” delivery services that the hosting provider underwrites.

Throw more bandwidth at it

This is needed both at the edge, in the “last mile,” and in the core. U.S. taxpayers already paid for build-out of broadband at the edge, in 1994, and got nothing for it. The Clinton-Gore administration’s “National Infrastructure Initiative” was supposed to rewire America with fiber optics. The various Bell companies agreed to rewire homes and public buildings in return for financial aid. Millions of households were supposed to get bi-directional, 45 Mbps traffic. But it didn’t happen.

There’s another problem with the edge: It’s asymmetric. The A in ADSL stood for this. Cable networks were designed to push hundreds of channels out to a household, but not to send much back upstream. Today’s symmetric protocols like peer-to-peer and videoconferencing overload the upstream channel. This is gradually changing, but it’s a costly overhaul.

In the core of the network, we’re still finding new ways to split the spectrum and get more bandwidth out of the fiber that’s already deployed. So it’s not a matter of digging trenches as much as it is of swapping out old Wave Division Multiplexing, switches and routers. In many cases, these devices were optimized for relatively short, request-and-respond traffic, so new patterns like P2P and streaming video don’t work as well for them.

Use better protocols

In other words, be more efficient with what’s available. One great example of this is video. Today, the de facto standard for one-way video is a Flash player. But look under the covers, and there’s tons of encapsulation. Video streams are stuffed into HTTP, which in turn goes inside TCP (and sometimes SSL). There’s a lot of overhead in this, not to mention the fact that TCP is a connection-oriented protocol that tries to deliver all bytes and isn’t well-suited to voice and video.

Protocol inefficiencies are one reason companies like Netli (acquired by Akamai), Riverbed and Peribit (acquired by Juniper) are able to squeeze huge performance increases from applications. They simulate inefficient protocols on both sides (to keep client and server happy) and fix them in the middle (where congestion occurs.)

But we rely on encapsulation and inefficiency because it works. Sure, we could stick video on a UDP datastream and get better, more efficient video with less bandwidth and better loss recovery. But our firewalls wouldn’t accept it. (Tunneling through domestic firewalls for voice traffic is one of the reasons for Skype’s market success where other consumer VoIP products failed; it also makes security types nervous.)

Taking away the carriers’ excuses

So the Internet needs several things:

  1. Core routers optimized for today’s two-way, multimedia traffic
  2. Domestic broadband similar to what taxpayer dollars already paid the telcos for more than 10 years ago
  3. Better protocols and smarter firewalls to squeeze every byte out of what we have

Without these three, carriers (and legislators) will take the easy route — traffic shaping — and claim that the loss of Internet freedom is simply a consequence of heavy traffic.

Technology-News: GigaOm

New Device Can Monitor Traffic On Wireless Broadband Networks

Data traffic management, viewed as a vile practice on the wired networks, could actually prove to be useful when it comes to the smooth functioning of wireless broadband networks, thanks to a novel new approach and technology developed by Bell Labs and introduced today by its corporate parent, Alcatel-Lucent.

In recent months, there has been steady growth in the number of wireless data users, who are sharing a finite amount of air spectrum and wireless resources such as airtime, RF channels and bandwidth. With the emergence of unlimited data plans, we might see more stress on the wireless data networks as more devices come online. The situation will get worse when 4G technologies like LTE start to get deployed.

What network operators would need is a new kind of networking management tool that goes beyond the current generation of tools that are geared towards voice quality. The traffic-shaping tools used on the wired networks are also of limited utility. So, Alcatel-Lucent, the somewhat humbled telecom hardware maker that counts wireless operators like Verizon amongst its customers, is introducing a new product that does precisely that. Canada’s Bell Mobility is currently running trials of this awkwardly named product, Alcatel-Lucent 9900 Wireless Network Guardian (WNG).

The Alcatel-Lucent 9900 WNG is composed of two network elements: a wireless network detector, for deployment in the data center, and a wireless network central, for deployment in a network or security operations center. The Alcatel-Lucent 9900 WNG monitors network traffic at a granular level, identifies anomalous wireless behaviors which could degrade network performance and impact subscriber’s experience.

Anyway, what WNG does is business allows carriers to better utilize their wireless data bandwidth. While on wired networks, the common belief that data is data hold true, but on wireless that is not the case. Alcatel-Lucent executives whom I met with last week insist that wireless e-mail data consumption is very different from, say, downloading files. Why? Because e-mail devices such as the BlackBerry are constantly polling the mail servers and keeping wireless data channels occupied. According to Alcatel-Lucent data, 1 MB of e-mail data consumes two hours of airtime and involves 1,500 signaling events while the same 1 MB on a P2P application takes 30 seconds and involves 0.3 signaling events.

The technology for the device has come from the bowels of the famed (if somewhat shrunken) Bell Labs. (It is part of a new plan to commercialize Bell Labs’ breakthroughs, according to Wim Sweldens, VP with Alcatel-Lucent Ventures.) It allows the carriers to find out the impact of a connection on the radios, towers and other wireless network elements.

Technology-News: GigaOm

Linux Advanced Routing & Traffic Control HOWTO

A very hands-on approach to iproute2, traffic shaping and a bit of netfilter.

netfilter: del.icio.us/tag/netfilter

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