Cambia Networks, a maker of wireless data networking equipment for mobile service providers, has announced its third-generation (3G) play in the form of the first-ever open-platform CDMA packet data system for bridging mobile devices to the Internet
Replacing expensive, dedicated packet data-server nodes and home-agent gateways, the system uses a general-purpose computing platform to achieve up to five times the density of current network access/bridging methods to allow it to handle fast-growing subscriber bases. At the same time, the system leverages the enormous economies of scale and widespread availability of third-party software and hardware development that an open platform can offer.
On top of that, Cambia provides its own proprietary management software and additional features such as firewall security and caching.
Devices like packet data-server nodes, or PDSNs, perform subscriber management for service providers. They give the user an IP address, marking billing records and performing authentication and service selection and everything else needed to establish and maintain a point-to-point protocol session between the user and the gateway.
While this model has worked fine for 2.5 and 3G wired and wireless networks, next-gen nets will require another model. "Unlike dial-up networks, 3G wireless connections will be always on," said Ikhlaq Sidhu, CTO at Cambia, referring to the end device potentially always having a connection to the core IP network.
"Unlike dial-up connections, where you might have 1,000 subscribers but in a busy hour you may only have 10% of them actually using the network, 3G networks require you to maintain some level of connectivity all the time," said Sidhu. "This puts enormous pressure on the central office in terms of equipment to support thousands of connections at any one time - and the subscriber base is growing," he said.
This is where Cambia's solution comes in, Sidhu said. "This type [3G] of subscriber management and routing capability at the gateway is very complicated, as every case is special with many layers of tunnelling," he said. "It's not simply a matter of sending a packet from the end user into the Internet, as every packet has a different protocol and requires special processing."
Cambia's solution is to borrow the enormous amount of low-cost processing power and memory from general-purpose computing platforms to allow the system to scale to the new requirements without re-inventing the wheel by designing proprietary systems from the ground up.
"Way too much time is being spent by system providers with separate teams for software, operating systems, system integration, backplane design, chassis design and support," said Sidhu. "Because of the inherent redundancy of designing from scratch, only 20% of what is offered to the service provider in the end is truly value-added," he said.
Cambia's CDMA Packet Data System 1.0 - which will be demonstrated at Supercomm next week - comprises 1U-high boxes, inside each of which are two Pentium 1GHz processors and up to 4Gbytes of memory. Each box can support up to 15,000 simultaneous subscriber sessions, so with up to 34 such boxes per 7 foot rack, the system can support 500,000 simultaneous sessions.
The boxes use the Linux operating system and are based on telecoms-compliant IBM X330 Series Servers that have been specially adapted for Cambia - making the system IBM's first move into gateway servers.
Key components of the system are the PDSN 3000, the CN 7000, 7500 (control node for PDSN and HA), the HA 5000 (home agent server) and the Radius Server (for secure authentication, authorisation and accounting). The CN manages all the other systems on the rack and polls each device for constant status updates. It also performs load balancing and insulates the radio node from the addition/subtraction of PDSNs. "As a result, you can add in more 'slices' to handle more data and subscribers - but the radio only has to know about the CN. You don't have to reprogram the radio to let it know you've upgraded the core network," Sidhu said.
"These platforms have huge economies of scale behind them," he said. "We're taking a hardware business and turning it into a software business. No one's ever thought of it this way before. It completely changes the cost structure of the business.
Key features from Sidhu's point of view - aside from leveraging a general-purpose platform - include improved system availability/reliability, security and the ability to cache within the same box.
The caching deserves special attention, considering the wireless context. "With TCP, if you lose a packet in wireless, it's often not appropriate to back off," said Sidhu. In addition, re-sending data in the bandwidth-starved wireless medium may also not be appropriate.
By placing a level of cache into the separating point between the wired and wireless mediums, the goal is to break the TCP connection between the two. "In doing that you can tune both of these connections appropriately to the link they're going over," said Sidhu. "As a result, you can get anywhere from 20 to 300% improvement in download speed - without an increase in bandwidth."
The "tuning," done with Cambia technology, involves things like timing of acknowledgements, deciding the packets to keep and data timeouts.
The system is available now for CDMA networks. A GSM version in the works leverages much of the work already done.