Nuage Networks uses SDN to tackle data centre networking bottlenecks

 Three planes of the network that host Nuage's .Virtualised Services Platform (VSP). Source: Nuage Networks

Alcatel-Lucent has set up Nuage Networks, a business venture addressing networking bottlenecks within and between data centres.

The internal start-up combines staff with networking and IT skills include web-scale services. "You can't solve new problems with old thinking," says Houman Modarres, senior director product marketing at Nuage Networks. Another benefit of the adopted business model is that Nuage benefits from Alcatel-Lucent's software intellectual property.

"It [the Nuage platform] is a good approach. It should scale well, integrate with the wide area network (WAN) and provide agility"

Joe Skorupa, Gartner

Network bottlenecks

Networking in the data centre connects computing and storage resources. Servers and storage have already largely adopted virtualisation such that networking has now become the bottleneck. Virtual machines on servers running applications can be enabled within seconds or minutes but may have to wait days before network connectivity is established, says Modarres.

Nuage has developed its Virtualised Services Platform (VSP) software, designed to solve two networking constraints.

"We are making the network instantiation automated and instantaneous rather than slow, cumbersome, complex and manual," says Modarres. "And rather than optimise locally, such as parts of the data centre like zones or clusters, we are making it boundless." 

"It [the Nuage platform] is a good approach," says Joe Skorupa, vice president distinguished analyst, data centre convergence, data centre, at Gartner. "It should scale well, integrate with the wide area network (WAN) and provide agility."

Resources to be connected can now reside anywhere: within the data centre, and between data centres, including connecting the public cloud to an enterprise's own private data centre. Moreover, removing restrictions as to where the resources are located boosts efficiency.

"Even in cloud data centres, server utilisation is 30 percent or less," says Modarres. "And these guys spend about 60 percent of their capital expenditure on servers." 

It is not that the hypervisor, used for server virtualisation, is inefficient, stresses Modarres: "It is just that when the network gets in the way, it is not worthwhile to wait for stuff; you become more wasteful in your placement of workloads as their mobility is limited."

 "A lot of money is wasted on servers and networking infrastructure because the network is getting in the way"

Houman Modarres, Nuage Networks

SDN and the Virtualised Services Platform

Nuage's Virtualised Services Platform (VSP) uses software-defined networking (SDN) to optimise network connectivity and instantiation for cloud applications.

The VSP comprises three elements:

• the Virtualised Services Directory, 
• the Virtualised Services Controller,  
• and the Virtual Routing & Switching module. 

The elements each reside at a different network layer, as shown (see chart, top).

The top layer, the cloud services management plane, houses the Virtualised Services Directory (VSD). The VSD is a policy and analytics engine that allows the cloud service provider to partition the network for each customer or group of tenants.

"Each of them get their zones for which they can place their applications and put [rules-based] permissions as to whom can use what, and who can talk to whom," says Modarres. "They do that in user-friendly terms like application containers, domains and zones for the different groups."

Domains and zones are how an IT administrator views the data centre, explains Modarres: "They don't need to worry about VLANs, IP addresses, Quality of Service policies and access control lists; the network maps that through its abstraction." The policies defined and implemented by the VSD are then adopted automatically when new users join.

The layer below the cloud services management plane is the data centre control plane. This is where the second platform element, the Virtualised Services Controller (VSC), sits. The VSC is the SDN controller: the control element that communicates with the data plane using the OpenFlow open standard.

The third element, the Virtual Routing & Switching module (VRS), sits in the data path, enabling the virtual machines to communicate to enable applications rapidly. The VRS sits on the hypervisor of each server. When a virtual machine gets instantiated, it is detected by the VRS which polls the SDN controller to see if a policy has already been set up for the tenant and the particular application. If a policy has been set up, the connectivity is immediate. Moreover, this connectivity is not confined to a single data centre zone but the whole data centre and even across data centres.

More than one data centre is involved for disaster recovery scenarios, for example. Another example involving more than one data centre is to boost overall efficiency. This is enhanced by enabling spare resources in other data centres to be used by applications as appropriate.

Meanwhile, the linking to an enterprise's own data centre is done using a virtual private network (VPN), bridging a private data centre with the public cloud. "We are the first to do this," says Modarres.

The VSP works with whatever server, hypervisor, networking equipment and cloud management platform is used in a data centre. The SDN controller is based on the same operating system that is used in Alcatel-Lucent's IP routers that supports a wealth of protocols. Meanwhile, the virtual switch in the VRS integrates with various hypervisors on the market, ensuring interoperability.

Nuage's Dimitri Stiliadis, chief architect at Nuage Networks, describes its VSP architecture as a distributed implementation of the functions performed by its router products.

The control plane of the router is effectively moved to the SDN controller. The router's 'line cards' become the virtual switches in the hypervisors. "OpenFlow is the protocol that allows our controller to talk to the line cards," says Stiliadis. "While the border gateway protocol (BGP) is the protocol that allows our controller to talk to other controllers in the rest of the network."

Michael Howard, principal analyst, carrier networks at Infonetics Research, says there are several noteworthy aspects to Nuage's product including the fact that operators participated at the company's launch and that the software is not tied to Alcatel-Lucent's routers but will run over other vendors' equipment.

"It also uses BGP, as other vendors are proposing, to tie together data centres and the carrier WAN," says Howard. "Several big operators say BGP is a good approach to integrate data centres and carrier WANs, including AT&T and Orange."

Nuage says that trials of its VSP began in April. The European and North America trial partners include UK cloud service provider Exponential-e, French telecoms service provider SFR, Canadian telecoms service provider TELUS and US healthcare provider, the University of Pittsburgh Medical Center (UPMC).  The product will be generally available from mid-2013.

"There are other key use cases targeted for SDN that are not data centre related: content delivery networks, Evolved Packet Core, IP Multimedia Subsystem, service-chaining and cloudbox"

Michael Howard, Infonetics Research

Challenges

The industry analysts highlight that this market is still in its infancy and that challenges remain.

Gartner's Skorupa points out that the data centre orchestration systems still need to be integrated and that there is a need for cheaper, simpler hardware.

"Many vendors have proposed solutions but the market is in its infancy and customer acceptance and adoption is still unknown," says Skorupa.

Infonetics highlights dynamic bandwidth as a key use case for SDNs and in particularly between data centres.

"There are other key use cases targeted for SDN that are not data centre related: content delivery networks, Evolved Packet Core, IP Multimedia Subsystem, service-chaining and cloudbox," says Howard.

Cloudbox is a concept being developed by operators where an intelligent general purpose box is placed at a customer's location. The box works in conjunction with server-based network functions delivered via the network, although some application software will also run on the box.

Customers will sign up for different service packages out of firewall, intrusion detection system (IDS), parental control, turbo button bandwidth bursting etc., says Howard. Each customer's traffic is guided by the SDNs and uses Network Functions Virtualisation - those network functions such as a firewall or IDS formerly in individual equipment - such that the services subscribed to by a user are 'chained' using SDN software.