Network optimisation continues to exercise operators and content service providers as their requirements evolve with the growth of services such as cloud computing. Cisco Systems' announced elastic core architecture aims to tackle networking efficiency and address particular service provider requirements.
“The core [network] needs to be more robust, agile and programmable”
Sultan Dawood, Cisco
“The core [network] needs to be more robust, agile and programmable – especially with the advent of cloud,” says Sultan Dawood, senior manager, service provider marketing at Cisco. “As service providers look at next-generation infrastructure, convergence of IP and optical is going to have a big play.”
Cisco's elastic core architecture combines several developments. One is the integration of Cisco's 100 Gigabit-per-second (Gbps) dense wavelength division multiplexing (DWDM) coherent transponder, first introduced on its ROADM platform, onto its router to enable IP-over-DWDM.
This is part of what Cisco calls nLight – intelligent light - which itself has three components: its 100Gbps coherent ASIC hardware, the nLight control plane and nLight colourless and contentionless ROADMs. “As packet and optical networks converge, intelligence between the layers is needed,” says Dawood. “Today how the ROADM and the router communicate is limited."
There is the GMPLS [Generalized Multi-Protocol Label Switching] layer working at the IP layer, and WSON [Wavelength Switched Optical Layer] working at the optical layer. These two protocols are doing control plane functions at each of their respective layers. "What nLight is doing is communicating between these two layers [using existing parameters] and providing the interaction," says Dawood.
Ron Kline, principal analyst for network infrastructure at Ovum, describes nLight more generally as Cisco’s strategy for software-defined networking: "Interworking control planes to share info across platforms and add the dynamic capabilities."
The second component of Cisco's announcement is an upgrade of its carrier-grade services engine, from 20Gbps to 80Gbps, that fits within Cisco's CSR-3 core router and will be available from May 2013. The services engine enables such services as IPv6 and 'cloud routing' - network positioning which determines the most suitable resource for a customer’s request based on the content’s location and the data centre's loading.
Cisco has also added anti distributed denial of service (anti-DDoS) software to counter cyber threats. “We have licensed software that we have put into our CRS-3 so that with our VPN services we can provide threat mitigation and scrub any traffic liable to hurt our customers,” says Dawood.
nLight
According to Cisco, several issues need to be addressed between the IP and optical layers. For example, how the router and the optical infrastructure exchange information like circuit ID, path identifiers and real-time information in order to avoid the manual intervention used currently.
“With this intelligent data that is extracted due to these layers communicating, I can now make better, faster decisions that result in rapid service provisioning and service delivery,” says Dawood.
Cisco cites as an example a financial customer requesting a low-latency path. In this case, the optical network comes back through this nLight extraction process and highlights the most appropriate path. That path has a circuit ID that is assigned to the customer. If the customer then comes back to request a second identical circuit, the network can make use of the existing intelligence to deliver a similar-specification circuit.
Such a framework avoids lengthy, manual interactions between the IP and transport departments of an operator required when setting up an IP VPN, for example. By exchanging data between layers, service providers can understand and improve their network topology in real-time, and be more dynamic in how they shift resources and do capacity planning in their network.
Service providers can also improve their protection and restoration schemes and also how they configure and provision services. Such capabilities will enable operators to be more efficient in the introduction and delivery of cloud and mobile services.
Total cost of ownership
Market research firm ACG Research has done a total cost of ownership (TCO) analysis of Cisco's elastic core architecture. It claims using nLight achieves up to a halving of the TCO of the optical and packet core networks in designs using protected wavelengths. It also avoids a 10% overestimation of required capacity.
Meanwhile, ACG claims an 18-month payback and 156% return on investment from a CRS CGSE service module with its anti‐DDoS service, and a 24% TCO savings from demand engineering with the improved placement of routes and cloud service workload location.
Cisco says its designed framework architecture is being promoted in the Internet Engineering Task Force (IETF). The company is also liaising with the International Telecommunication Union (ITU) and the Optical Internetworking Forum (OIF) where relevant.