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High-end routers rise to meet Exabyte challenge

High-end routers from Cisco, Juniper, and Brocade, are designed to meet the Exabyte Internet traffic level challenge.

With IT networking equipment, capacity is everything - more so now as router manufacturers compete to give communications carriers and service providers the extra bandwidth and processing power that they need to deliver on-demand Cloud Computing capabilities to both businesses and consumers, and superfast broadband connections right into the home.

Predictions by Cisco, whose annual Visual Networking Index (VNI) examines potential for global traffic growth from a wide range of Internet connected devices, from computers and game consoles to TVs and webcams, and looks at data traversing fixed and mobile, public and private, IP networks, suggest Internet traffic will quadruple to 767 Exabytes (one exabyte equals around a billion gigabytes) by 2014. This growth will be driven by latency-dependent traffic types - in other words, applications for which assured high-speed connections are a prerequisite if they are to work at all.

An explosion in data in 2013 will be driven largely by various forms of video, including IPTV, video-on-demand, and video/audio streaming, Cisco believes, making up over 91 per cent of all traffic. Besides video, other contributors to online traffic growth are likely to include peer-to-peer file sharing, Cloud Computing, and remote back-up services. Add to all that online gaming, virtual worlds, and relatively conventional websites that like to use multi-megabyte high-resolution images.

If those figures are correct, and irrespective of its precise source, all that data is likely to put considerable strain on core routers within telecommunications networks, with carriers and service providers forced to upgrade their existing infrastructure to keep information flowing without interruption.

This is not new news to the industry that facilitates the communications networks. Analyst findings indicate that carriers are fully aware of the challenge, and are ramping-up spending on new routers in preparation. Twenty years of nigh-on non-stop growth levelled out in the noughties, partly due to market saturation, and the fact that many installed devices had yet to achieve full use. IDC forecasts calculated the router market rebounded in the first quarter of 2010 after four quarters of declines, for example, with revenue up 15 per cent year on year.

The majority of that revenue (72.7 per cent) came from sales to telecommunications carriers and service providers, however, with enterprises having less money to spend on in-house infrastructures, allied to a renewed taste for outsourcing that usually accompanies financial uncertainty. Multi-service edge routers (those that accommodate different types of switching and routing protocols, like IP, ATM, SONET/SDH, and MPLS, for example) grew the most, 36.8 per cent year on year, driven largely by data centre and Cloud Computing initiatives from service providers.

Bandwidth, bandwidth, bandwidth

To meet that demand, router makers including market leader Cisco and rivals Juniper Networks, Alcatel-Lucent, and Huawei, have developed high-capacity core routers, which are only this year becoming widely commercially available.

Introduced in March 2010, for example, the world's most powerful router is Cisco's CRS-3 router (CRS stands for 'carrier routing system'), which offers up to 322Tbps of aggregate data throughput, tripling that of its previous model the CRS-1, first launched in 2004.

'Many may think we will never need that much bandwidth, but the enterprise future of mobile TV, streaming media, YouTube, telepresence, and 3D HDTV surely demands it,' wrote Yankee Group analyst Zeus Kerravala at the time.

Carriers and service providers like AT&T, Comcast, and Verizon - whose networks and data centres handle huge amounts of Internet traffic - insist that the capacity will eventually be justified, and are now conducting trials; but for the moment, most service providers are still migrating from 1GbE to 10GbE, with a few starting to adopt 40GbE.

100Gbps ethernet

At the heart of these capacity gains are a new interface: 100Gbps Ethernet, known as 100GbE. Cisco's previous most powerful router, the CSR-1, used line cards that featured a single 40Gbps interface - the CRS-3 has simply swapped out the switching card on the old CSR-1 backplane to support line cards which feature a 40Gbps and a 100Gbps interface.

The 322Gbps figure comes from running 140Gbps per slot (made up of a 40Gbps and 100Gbps interface card in each), with a switching capacity of 4.48Tbps (Terabits per second) per chassis (16 slots per chassis, and double the per slot capacity because both incoming and outgoing traffic are counted simultaneously), with 72 chassis together providing the 322Tbps total - each individual chassis (costing $90,000 a time) only offers 3.92Tbps of capacity.

Not that Cisco's rivals are standing still on the capacity front. While none can yet match the CSR-3's multi-chassis 322Tbps benchmark, Juniper Networks introduced the first 100GbE router interface card for its T1600 core router last year, as did Alcatel-Lucent for its 7750 Service Router, promising to pack 10 100GbE interfaces into one-third of a rack before the end of 2010.

Chinese vendor Huawei has also developed prototype 100GbE router interfaces, which will eventually be incorporated into its routers, while Brocade Communications (which acquired Foundry Networks in 2008), and other router manufacturers are likely to follow.

Despite the frenetic vendor product development, it should be remembered that no formal standard for either 100GbE or even 40GbE technology has yet been ratified by the respective industry technology bodies - the fastest published standard for Ethernet remains 10GbE (there is a 40Gbps networking standard based on wave division multiplexing (WDM), which trunks four 10Gbps signals onto one optical cable, however). Until the IEEE 802.3ba standard is ratified, this means that compatibility with different types of physical layer (PHY) standards and interfaces to both optical and copper cabling systems, or the ability to push Ethernet frames over distances of 100m or more, is not yet assured.

Virtualisation access

When it comes to optimising router performance, raw throughput power is not the only factor; the intelligent handling and routing of packets also makes a major contribution. Perhaps the most remarkable thing about Cisco's CSR-3 router is actually an integrated technology called the Network Positioning System (NPS). This uses routing protocols to identify the shortest path to virtualised servers or storage resources, then connects users to these systems through an MPLS virtual private network (VPN), providing a more secure connection to Cloud Computing services. When too many users are trying to access those resources, NPS will direct service requests to other virtualised systems within a different data centre in the cloud to spread the load, all without interruption to the service, Cisco says.

The company is trying to standardise the NPS method of determining resource proximity in the IETF's application layer traffic optimisation working group (ALTO WG), while other manufacturers have slightly different approaches to much the same thing.

Juniper - arguably Cisco's foremost rival and certainly Cisco's most ardent challenger - announced an open platform for third-party software development, which it hopes will materialise similar capabilities. Junos Space and Junos Pulse will support both Juniper-developed and third party applications intended for network-based programs, with a Juniper example being Route Analyser, a program that optimises paths between data centres and Service Now, which performs network diagnostics to locate problems.

Juniper's Junos OS has long been something of a trump card in its rivalry with Cisco, providing an easy-to-use command line interface (CLI) which many network engineers prefer to Cisco's IOS equivalent, which some complain is also susceptible to downtime when adding features or managing bugs.

Junos has been modified to scale up to 10 million concurrent user sessions, meant to help with operators and service providers providing Cloud Computing services to large numbers of people. Enhancements to the SRX services gateway are designed to secure traffic flows between different servers, VMs and mobile clients, for example, and boost security by integrating user and application identity into VLANs and virtual private LAN services.

Core versus edge

Vendors disagree on whether this sort of functionality is best located in the core of the network or at its edge, where it is closer to end-users. Core routers were traditionally designed to forward data between other core and edge routers, whereas edge routers provide the on-ramp for customer traffic onto the Internet. However, such approaches hold good only for as long as the infrastructural models on which they are predicated are deemed effective. It is evident that deployment models have changed in the last decade, and routing models have evolved accordingly.

Cisco says most traffic patterns are now between data centres, rather than from the service provider or the business or consumer and back again. This, it says, means performance can be most enhanced by dealing with traffic congestion in the core, which has greater visibility into a broader set of physical and virtual resources. Other vendors - most notably Alcatel-Lucent and Huawei - refute this: they contend that that sort of functionality should be optimised at the edge, where services are originated and delivered.

Other core router features are fairly standard and are present in most manufacturers' equipment in some guise or other: most routers already have support for IPv6 as well as IPv4, for example, and are built to handle legacy optical infrastructure like SONET, as well as metro dense wave-division multiplexing (DWDM) - a technology that some have touted as 'the future of optical telecommunications in the metro market'. Remote configuration is increasingly included by default, as is high quality of service to support server and application virtualisation in the data centre.

Chips and power

With the cost of supplying electricity to data centres escalating, router manufacturers are keen to provide extra capacity without consuming additional power, and so have focused on developing their own energy efficient CPUs to help them achieve this. Alcatel-Lucent's 100GbE-enabled 7750 Service Router will use the company's own FP2 silicon, a 90 nanometre chipset using 112 array cores to get 95,000 million instructions per second, while keeping power consumption below four watts per gigabit (Wpg), for example.

Other vendors are also on the energy-usage case. Cisco's CSR-3, meanwhile, consumes only 2.75 Wpg, the company claims; and Juniper's new 'Trio' CPUs built into line cards offering 16 10GbE ports on its T1600 routers use around 37 watts per port (3.7 watts per Gbps).

Unified architecture

Cisco and Juniper are also competing to provide unified software platforms, or 'fabric interconnects', which link routers to other data centre resources, like servers, storage, local area network (LAN) switches, and other appliances to save power and boost efficiency. Introduced in 2009, Cisco's unified computing system (UCS) is geared to supporting Cloud Computing service delivery, using standard components to reduce data centre operational costs and make it easier to manage physical and virtual systems and applications as a single pool of resources.

The idea is to promote Ethernet as a single transport mechanism between all connected equipment in the data centre, rather than the mishmash of different technologies - including Fibre Channel (a gigabit-speed network technology primarily used for storage networking) and Infiniband (a switched fabric communications link), which tend to be used now.

Not to be outdone, Juniper has launched a similar platform, called the 'Stratus Project', which will eventually support the same converged enhanced Ethernet (CEE) data centre fabric specifications being endorsed by several manufacturers, including Cisco, Brocade, and Force10 Networks, as well as server and storage makers IBM, EMC, NetApp, Sun Microsystems, and Fujitsu.

The sparky Cisco-Juniper rivalry has been ongoing for nearly 15 years now, and shows no sign of abating, which can only be a good thing for the ongoing development of the router market overall. Before the ambitious Juniper popped up in the late 1990s, Cisco had built market dominance by out-selling or acquiring potential rivals, and the generation of competitor that it has had to face since then has certainly prevented the networking giant from nursing any tendency toward complacency.

The networking market has tended not to attract the kind of mainstream coverage enjoyed by the PC and mobile device sectors, for example, but the technological progressiveness of this market has always been white hot, and the work taking place in the R&D departments of the leading router vendors is among the most advanced to be found anywhere; and it is still finding ways to extract more from what is, in essence, conventional core technology: we still have the promise of photonic switching to reach maturity.

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