Cisco fortifies its fibre gear for metro and long haul

Cisco Systems Inc. rolled out enhancements to its optical portfolio designed to increase the channel count on its metro and long-haul transport platforms, at the National Fibre Optic Engineers Conference last month in Baltimore.

For long-haul connections, Cisco doubled the channel count of its ONS 15800 dense wavelength division multiplexing (DWDM) system, from 32 wavelengths, at 10 Gbps each, to 64 wavelengths. This was achieved by amplifying the L band of the fibre to utilize 1565-nanometer to 1605-nm wavelengths, and by employing out-of-band forward error correction (FEC), which helps overcome bit errors introduced by dispersion and attenuation.

Out-of-band FEC uses seven per cent of the payload in a 10-Gbps channel to correct errors in a signal, Cisco officials said. By decreasing the amount of bit errors in a transmission, FEC also helps increase span lengths and channel counts, they said.

Cisco considers the “sweet spot” for the 15800 to be distances from 600 km to 1,600 km. The company is playing the long-haul market conservatively, as competitors like Nortel and Ciena say carriers now require spans up to 4,000 km and channel counts as high as 160 to 320 for ultra long-haul applications.

Cisco said its conservatism is driven by the requirements of IP (Internet protocol) traffic in the optical domain. That’s not to say that Cisco’s progress in optical networking is slowed by its legacy in IP routing, however.

“All IP/optical interactions are standards-based,” so there is no proprietary link-up between Cisco routers and DWDM gear, said Carl Russo, group vice-president of optical networking at Cisco. “We will achieve market share based on the merits of our (optical) products.”

Of the ambitions of Ciena and Nortel, Russo said, “They’re not overhanging the market; there’s just a long time horizon” for the 1.6 terabit/sec to 3.2 terabit/sec channel capabilities over 4,000 km. “But ultra long-haul sales cycles are longer, so you need to let carriers know ahead of time.”

Nortel is particularly aggressive, having put a stake in the ground earlier this year for 40/80 Gbps-wavelength capabilities. That market, Russo said, will emerge “maybe in my lifetime, but not in my vesting period.”

He also says carriers purchase products based on dollars per bit per mile, not on “cool” terabit channel counts or distance figures like 4,000 km.

“Amplification is not free,” Russo said.

Cisco said it now has 25 customers for the 15800 ONS, including Cogent Communications, Cambrian Communications, Telecom New Zealand and Velocita, an emerging carrier in which Cisco has about a (US) half-billion dollar stake, comprised of equity and equipment financing. Cisco obtained the ONS 15800 in the December 1999 acquisition of Pirelli.

For the metro, Cisco said its ONS 15454 transport system successfully completed Telcordia’s OSMINE process for operational support system (OSS) integration, a major hurdle in fortifying the system for ILEC (incumbent local exchange carrier) deployment. Telcordia OSSes support 80 per cent of the established telco networks worldwide, and Cisco can now sell the ONS 15454 into the US$3 billion ILEC market, company officials said.

Cisco also added 32-channel DWDM capabilities to the ONS 15454, which doubles the OC-48 density of the system. Cisco said the ONS 15454 can now enable service providers to increase capacity between two points on a metro ring without burdening the rest of the ring.

This capability alleviates “ring stacking,” in which the entire metro ring has to be upgraded with additional capacity even though high-growth routes may only be between two points on the ring.