The Next-Generation LAN

A dizzying array of new applications are crowding onto the LAN. Among the most challenging in terms of performance and design are videoconferencing, video surveillance, virtual desktop infrastructures, and converged storage.

What's that? A unified communications or virtual desktop vendor says your current network can handle its systems just fine? We've heard that one before--and then the help desk lines lit up.

The reality is IT must sniff out problems now and build in plenty of room to grow, because the math for sensitive traffic is not nearly as easy as vendor reps would have you believe, and users generally give us one chance to have new productivity apps catch on.

Or maybe your storage group is looking to upgrade to Fibre Channel over Ethernet, a nascent technology that may ultimately do away with SANs as we know them. Far from being fearful of FCoE, LAN managers should embrace this development, because placing storage traffic on the network in the form of raw SCSI communications allows for a more efficient data center footprint. No duplicate infrastructure needed to handle writing data to disk arrays. This convergence lowers not only cabling requirements and costs, but also energy, cooling, and physical space demands.

Of course, storage traffic needs to be delivered without any packet loss and as quickly as possible. While UC performance problems become evident through frozen frames, choppy voice, or the inability of your security team to see in a particular area of the building, storage performance glitches will manifest via delayed reading and writing of just about everything.

In our full report, available free for a limited time at informationweek.com/ analytics/nextgenlan, we discuss how to diagnose common problems that plague LANs and recommend strategies to prepare for the next generation of applications--and no, throwing large amounts of bandwidth at the problem isn't the answer. For example, as virtual desktops become more common, latency and jitter will have the potential to kill more than just video and audio streams, as lots of small packets for keyboard, video, and mouse updates scurry back and forth. For FCoE and other IP-based storage specifications, problems could derail backups. So let's look at what's different about this new traffic.

Video Killed The LAN Star

The poster child for LAN problems is high-definition video, both room- and desktop-based. Most major UC vendors have HD videoconferencing systems shipping now, and the move to adopt this technology to provide inter- and intracompany communications is gaining momentum--and stressing both local and wide area networks. For example, the 585 business technology professionals responding to our InformationWeek Analytics February 2010 WAN Optimization survey say applications that require real-time performance--like VoIP, streaming video, and videoconferencing--are top concerns.

Desktop HD videoconferencing is being promoted at speeds as low as 1 Mbps to 1.5 Mbps for 720p quality. These numbers are based on H.264 compression standards and are single-screen estimates. Room-based systems are typically multiscreen and promise maximum quality, and thus operate in the 1080p range. For these systems, expect to generate 5 Mbps to 6 Mbps per screen and to pile on additional content-sharing options, such as whiteboarding and/or multimedia. Depending on the mix, these can bring another 5 Mbps to 6 Mbps of bandwidth to the party.

Think you're all set because you have 100 Mbps to the desktop and 1 Gbps of uplink bandwidth? Consider that most of the networks that we evaluate have that same capacity but aren't ready to handle either of these types of traffic because of rampant packet loss at critical network aggregation points. HD videoconferencing, like many new applications, has almost no margin for error on the network.

We've used videoconferencing as our example, but the message applies to many applications and comes down to this: To support the next wave of real-time traffic, your network must be more reliable, perform better with fewer discards, and be more efficient than even a few years ago. And optimization and efficiency requirements are driven as much by business factors as by applications or services. No organization can afford to leave half of its LAN bandwidth unutilized. One positive trend is that vendors and standards bodies are developing techniques and technologies to help IT organizations solve these problems.

Jeremy Littlejohn is CEO of RISC Networks, a firm that helps IT groups optimize their infrastructures.

Write to us at [email protected].