Cisco unveils IP-over-DWDM support for CRS-1 platform

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As the latest facet in the network convergence layer of its Internet Protocol Next Generation Network (IP NGN) architecture, Cisco Systems (San Jose, CA) has enhanced its CRS-1 carrier routing system to include support for what the company calls IP over DWDM (IPoDWDM).

Designed to facilitate “seamless element, control, and management integration” among the IP and DWDM layers of carrier networks, the IPoDWDM platform allows service providers to more efficiently manage increased network traffic resulting from deployment of video/IPTV services, says Cisco, while enabling a fourfold increase in throughput for existing DWDM infrastructures.

Cisco's IPoDWDM platform comprises two modules for the CRS-1 router, both designed to lower operational costs by eliminating bulky optical transponder gear from service providers¿ networks.

According to Deb Mielke, managing director at Treillage Network Strategies (McKinney, TX), the IPoDWDM platform “definitely marries IP much closer to the optical network-which is something that has to happen.

“It also gets back to reducing the number of ‘piece’ parts in the network,” observes Mielke. “The more stuff you have to manage and provision and spare, the more it costs-and as the processes get more complex, the more chances there are for things to go wrong.”

The IPoDWDM platform comprises two modules for the CRS-1 router, both designed to lower operational costs by eliminating bulky optical transponder gear from service providers’ networks. Tunable on the C-band across 50-GHz spacing, both modules connect directly into existing DWDM infrastructure and are designed to minimize optical-electrical-optical (OEO) conversions in networks by eliminating the need for short-reach interfaces among routers.

“Using our approach, what service providers can do is take those transponder shelves and the functionality that was resident in those before and integrate them right into the router itself,” explains Kelly Ahuja, vice president of Cisco’s carrier core multiservice business unit. “All of a sudden, they can remove those transponder shelves completely. The router now can send out what we call colored wavelengths, or 15XX long-reach wavelengths, directly into the transmission gear.”

The platform’s primary component, the 1-Port OC-768c/STM-256c Tunable WDMPOS Interface Module (HKFO6244), provides up to 40-Gbit/sec data throughput across existing 10-Gbit/sec DWDM systems.

“We introduced a 40-gig OC-768c interface on the router last year, which was basically a packet-over-SONET interface,” notes Ahuja. “What we’ve done is actually taken that packet layer or Layer 3 interface and attached to it a specialized transponder technology [that] allows us to carry that 40 gigabits of data traffic over a standard 10-Gbit/sec transmission link, [employing] some proprietary modulation schemes in the optical domain.”

The platform’s second component, the 4-Port 10GE Tunable WDMPHY Interface Module (HKFO6244), supports G.709 Generic Forward Error Correction (GFEC) technology as well as “router-to-router” operations, administration, maintenance, and provisioning (OAMP) capabilities. Ahuja says the four-port 10-Gigabit Ethernet module’s “WDMPHY” interface is “essentially Ethernet, but [provides] SONET or SDH-like performance management…at Ethernet price points.”

The company claims the modules’ integrated FEC capabilities can provide up to a 5x increase in network reach, while facilitating up to a 50% reduction in optics. Both interfaces are compatible with the company’s ONS 15454 Multiservice Transport Platform (MSTP), as well as interoperable with third-party DWDM systems.

One of the platform’s more salient features, according to the company, is “control plane integration” via GMPLS segmentation. “By using our segmented GMPLS [S-GMPLS] approach, we’re able to provide segregation of management and make GMPLS realizable inside the service provider’s operational environment,” explains Ahuja. “Within the router, we actually create multi-instances of routing-one half of the routing instance belongs to the optical domain, and the other half of the routing instance belongs to the IP domain.”

The company says its S-GMPLS technology leverages the power of GMPLS IP control protocols for autoconfiguration of wavelengths, while keeping the topology of the routing domain isolated from the topology of the DWDM domains, providing a way to deploy GMPLS while respecting providers’ organizational boundaries. The IPoDWDM platform also interoperates with the company’s ROADM-based products and transponders.

The company says the platform’s high level of integration provides a flexible operating model to enable separate management of IP and DWDM equipment by separate operating groups. Such integration, according to the company, also enables providers to migrate from manual provisioning processes to a “dynamic service activation provisioning process.”

Ahuja contends that “all this put together means a tremendous amount of capex and opex savings for the operators, along with the ability to address the growing need to increase network traffic at the lowest possible incremental cost.”

Trelliage’s Mielke concurs, saying the platform’s main benefit is that it allows service providers to focus solely on segmenting different kinds of network traffic, such as consumer versus enterprise, or voice and video versus data.

“If you can segment this stuff, then you can apply things like quality of service, service availability, reliability, service level agreements, etc.,” concludes Mielke. “That gives service providers a lot of flexibility, not only in the way they manage services, but in how they charge people. A lot of the carriers’ transport groups and IP groups are different, but the way [Cisco] has put together the management systems and the way the CRS-1 works, it still allows those two groups to manage ‘their piece,’ without any political conflict.”

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