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Rapid IP traffic growth drives need for greater 10 GbE port density

As NTT America saw its carrier customers fend off IP traffic growth by gobbling up 10-Gigabit Ethernet, port density became a problem for the wholesale IP backbone transit provider. With the Cisco ASR 9000, NTT America halved its edge router footprint and expanded its capacity.

While wireless carriers tremble at the prospect of an oncoming data tsunami flooding their networks, wholesale transit provider NTT America, the U.S. subsidiary of Tokyo-based NTT Corp., has for years been knee-deep in managing rapid Internet Protocol (IP) traffic growth and the demand for fatter pipes.

NTT America had been feverishly updating line cards in its decade-old Cisco Systems' Catalyst 6509 switches located in its 11 U.S.

We have now exceeded 300 gigabits of capacity between the U.S. and Japan on our international network.
Doug Junkins
CTO and Vice President of IP EngineeringNTT America
point-of-presence (POP) facilities to meet its carrier customers' needs at the edge. But scaling its network infrastructure to support IP traffic growth soon became unmanageable.

As end users consumed more bandwidth-hungry, real-time content and applications over the Internet, NTT America's carrier customers gobbled up a rapidly diminishing number of bundled 10-Gigabit Ethernet (10 GbE) ports on those 6509s, said Doug Junkins, CTO and vice president of IP engineering at NTT America.

Even NTT's own operations were cramming the pipes, never mind its carrier customers' contributions to IP traffic growth. About 90% of homes and businesses in Japan are expected to have fiber to the home (FTTH) by the end of 2010, delivering 100 Mbps connections to consumers, Junkins said.

"We have [carrier] customers today on our network that have more than ten 10 GbE connections bundled together … [so] we've had to invest a lot of money in expanding the capacity of our network, both domestically as well as international links," he said. "We have now exceeded 300 gigabits of capacity between the U.S. and Japan on our international network."

Scaling up port density to meet IP traffic growth

Junkins predicts it won't be long before 100 Gbps networks become the norm for the Internet backbone. But meeting that demand would have been unrealistic -- financially and logistically -- with the switches NTT America was using in its edge network last year, he said.

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Puny port density in the Cat 6509s was the culprit, Junkins said. The switches supported up to 28 10-GbE ports, requiring NTT America to run up to four of them in any given facility to meet intensifying IP traffic growth. Having to buy multiples of equipment not only increased capital outlays, it had two other strikes against it -- more boxes consumed more power and space in the POPs.

"Continuing to scale by adding more 10 Gigabit Ethernet bundles only gets us so far, so we need a higher-speed connection that will be a much greater [remedy for IP traffic growth]," Junkins said. "We were starting to see the [port] density [limitations] of the number of 10-gigabit ports we could provide."

Looking for the answer to scaling capacity to meet IP traffic growth, Junkins started more than a year ago to evaluate platforms from Cisco, Juniper Networks, Brocade and Force10 Networks. He selected the Cisco Aggregation Services Router (ASR) 9000, a carrier-class edge router with eight times the port density of the Cat 6509s. Today, they have capacity for 64 10 GbE ports, and Cisco plans to expand that port density to 160 10 GbE ports.

The Cisco ASR 9000 takes the same amount of rack space as the Catalyst 6509 despite the greater port density, Junkins said.

< p> Although it consumes more energy than the Cat 6509s, he said, the Cisco ASR 9000 consumes less energy per port, and each POP needs only two of the edge routers to meet bandwidth demands from rapid IP traffic growth.

The rollout of Cisco ASR 9000s across NTT America's 11 POPs will be gradual. As Catalyst 6509s get decommissioned from some facilities, they will be repurposed at POPs getting refreshed later to temporarily boost capacity at those sites, Junkins said.

"They're shipping today the density of 10-gig ports that we really needed in order to be able to keep growing our network without holding up our installs for customers," he said. "It brings the capacity in line with the [IP traffic growth] we saw."

It's a problem all carriers will face as IP traffic growth outpaces the capacity of their legacy infrastructure, according to Greg G. Smith, a marketing manager within Cisco's service provider unit. At peak capacity, the Cisco ASR 9000 is capable of 6.4 Tbps, he said.

"[Older equipment] was sufficient for them when [carriers] didn't need as much capacity, but now you've got a lot more services," Smith said. "Ten years ago, you didn't necessarily have people running voice and video on-demand … on a single IP infrastructure. There's an almost insatiable demand for greater connectivity."

Let us know what you think about the story; email: Jessica Scarpati, News Writer

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