Wednesday, July 02, 2008

Bandwidth Multiplication to the Rescue

If you think that you feel constrained by your WAN or Internet connection bandwidth, imagine the dilemma the service providers are in. Just when they thought that they'd invested enough in trenching fiber, expanding network capability and upgrading router speeds, along comes a killer app like video. In this case "killer" means bandwidth killer. When you've found that your bandwidth margin is much less than you expected, what can you do besides start over? How about speeding up what you've got?

Comcast and Cisco are testing a way to do just that. They've managed to multiply Comcast's fiber infrastructure by a factor of x10 using the latest in DWDM (Dense Wavelength Division Multiplexing) transmission equipment. That's 100 Gigabit Ethernet, 100 GigE.

What's important about this is that the setup used Comcast's existing fiber optic backbone that runs between Philadelphia, PA and McLean, VA. No new fiber was trenched. Instead, fibers already in the ground simply carried more data per wavelength.

Simply might be an understatement. The terminal equipment is Cisco's CRS-1 Carrier Routing System. It's part of Cisco's IP Next Generation Network architecture that scales to... are you ready for this ...92 Tbps of switching capacity. Yes, 92 Terabits per second of traffic. All of a sudden 100 Gigabits per second seems like the slow lane. But for long haul network operators 100 GigE will do just fine for now, thank you. It should be awhile before users start demanding Terabit connections. At least that's what everyone hopes.

Video streaming and downloads are now the majority of packets on the Internet. The Internet may have started as an information service envisioned as primarily text or text plus graphics. But the definition of information content has expanded to include voice, data acquisition, and high definition video. Video over IP is no longer the coming thing. It's here. From YouTube to TV program segments, to full length television programs and movies, video is sopping up as much bandwidth as it can get. In that context 100 GigE delivery networks are no longer an extravagance. They're the next benchmark.

Wavelength Division Multiplexing (WDM) advancements offer a means to increase network capacity by upgrading terminal equipment and using the same fiber strands. It comes down to more densely packing individual wavelengths using more accurate and stable lasers. Beyond that, network operators will have to press more dark fiber strands into service to multiply their available bandwidth.

Transmission efficiency improvements haven't been limited to fiber optic networks. The buried asset of twisted pair copper is also being asked to transport higher bitrates by upgrading terminal equipment to improved modulation techniques and active interference cancellation. It's common now to be able to get 10 Mbps and even 100 Mbps Ethernet services delivered over copper from nearby carrier POPs (Points of Presence) using lines once thought to be limited to T1 levels of 1.5 Mbps.

Bandwidth multiplication on both fiber and copper transmission lines has lead to the availability of higher bandwidths at lower prices for business users, and residential customers as well.

Click to check pricing and features or get support from a Telarus product specialist.

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