NE Nov 2009

Service providers continually upgrade their networks, but as soon as they tackle one problem, another arises. Given the rapid clip at which broadband traffic is growing, it is the access network that is demanding the operators' attention.

For wireless, uptake of 3G dongles and smart phones means operators are upgrading cellular sites to backhaul rapidly growing mobile broadband traffic. Meanwhile, the capacity of fixed broadband links to the home is also on the rise and broadband rates of 50 and 100Mbit/s are becoming common. Such traffic growth is leading to subtle changes in the access network.

While Ethernet is replacing the ATM and T1/E1 lines used for wireless backhaul, greater intelligence is needed to handle the various traffic flows. An operator's IPTV service is treated differently to a YouTube video delivered over the internet, but both streams have requirements different to voice packets. The access network must process the various packet payloads in a smarter way.

These developments explain why two chip companies – EZchip and Wintegra – are coming to market with network processing families.
EZchip's NPA family targets fixed access and wireless backhaul. "Until recently, our focus was the high speed segment – edge routers and switches further from the subscriber," said Amir Eyal, EZchip's vice president of business development.

For fixed access, NPAs will process traffic from aggregation platforms, such as DSLAMs and fibre based passive optical networking units – or optical line terminals – that aggregate traffic from tens of homes or buildings. For wireless, the devices will process basestation traffic.

Meanwhile, Wintegra has launched the first members of two families: WinIP3, focused on fixed access; and WinPath3, for wireless applications such as LTE and WiMAX. These are Wintegra's third generation devices for access, tailored for Ethernet and IP. "By removing legacy support, we're removing cost from the WinIP3 devices," said Gordon Lawton, European sales and marketing director.

EZchip's NPAs are 10Gbit/s data plane processors that classify and route packets. They also have end to end network awareness – equivalent to supporting layers 2 to 4 of the OSI reference model.
The devices can buffer incoming packets, but use external memory when scheduling outgoing packets. The NPAs are rated at 10Gbit/s, but can handle traffic over subscription: the NPA-3 has up to four 10Gbit/s ports and memory can be used to buffer packet bursts in excess of 10Gbit/s.

At the core of the NPA architecture are four 'flavours' of task optimised processors (TOPs): parsing; searching using look up tables; packet modification; and packet forwarding.

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