Tabula's ABAX family of 3PLDs addresses a wide variety of wireline applications including packet processing, network timing, framing and mapping, ATM cell processing, and security and has on chip support for a significant number of communications standards including PCI Express; Xaui; Gigabit Ethernet, and SGMII.

The wireline industry has also undergone a lot of changes and is expected to undergo even greater changes in the upcoming future. Many of the network infrastructure changes are being driven by the demanding bandwidth requirements of video applications.

The wireline infrastructure can be partitioned into four major segments:

• Access
• Metro
• Core
• Enterprise

The enterprise market includes equipment such as routers and switches that are similar to those deployed by Network Service Providers in the public network. Thus the design challenges and opportunities for equipment in this market are the same as that for Service Provider equipment. Moreover, there is a growing trend for enterprise equipment to require Carrier-Class features as up-time and scalability become increasingly more important in enterprise networks and large data centers.

Figure 1 depicts the wireline infrastructuure, simplified for comprehension purposes. Recent upgrades to the network have focused on increasing the bandwidth capacity on all parts of the network, but particularly in the Access portion since this portion is a key bottleneck and is also closely tied to revenue-generating services.

Upgrades to the network have also focused on evolving the overall network into a more simplified "all-IP" structure. This involves eliminating the disparate legacy circuit switched PSTN network and creating separate service and transport layers. With that, all applications and services - ranging from voice, video and Internet data (the so-called "triple-play") - can all be implemented on top of a single physical network, reducing OPEX costs for the Network Service Provider.

Figure 1 shows next generation development work highlighted in green. The major thrust behind the next generation development is twofold: demand for bandwidth and Carrier-Class Quality of Service.

DEMAND FOR BANDWIDTH

Video applications are straining the wireline infrastructure. Witness the popularity of Internet sites such as YouTube and Hulu. In addition, many Internet video sites are increasingly adopting more high-definition video content. Add to this new IPTV video platforms such as AT&T U-verse TV and you can begin to project that demand for high-bandwidth-consuming video applications may someday exceed what the entire wireline infrastructure can provide.

To address this, Network Service Providers and Network Equipment Vendors are working on developing new higher capacity solutions such as Next-Generation PON, with bit rates running at 10 Gbps, for the Access Network Service Providers and Network Equipment Vendors are working on developing new higher capacity solutions such as Next-Generation PON, with bit rates running at 10 Gbps, for the Access Network and Next-Generation Carrier Ethernet solutions, with bit rates running at 40 Gbps or 100 Gbps, for the Metro Network.

The industry standards for these solutions are still in development at this time. In the case of the North American Telco preferred ITU-T flavor of PON, the standards discussions for XG-PON (the 10 Gbps Next-Gen version of GPON) have just recently started and are not expected to be completed until around 2012¹.

CARRIER-CLASS QUALITY OF SERVICE

Another driver behind the development of next generation wireline networks is Carrier-Class Quality of Service. As the network transitions over to an "all-IP" data network, quality of service becomes much more important. Packet data networks allow for the sharing of capacity resources, unlike legacy circuit-switched networks where dedicated bandwidth resources must be allocated. Thus a Service Provider does not need to overbuild its packet data network as it would with the circuit-switched network, allowing it to maximize its return on the infrastructure investment. However, the packet data network must be able to respond properly during congestion and traffic overload situations. Because bandwidth capacity resources are shared among different applications, different users and different service tier agreements, mechanisms must be in place within the network to prioritize and appropriately discard traffic. Such mechanisms and handling of traffic is often referred to as Quality of Service (QoS).

Much focus on next generation networks has been on implementing QoS mechanisms. More specifically, much effort has been spent on developing infrastructure equipment so that its QoS capabilities match the service quality one would have obtained using the legacy circuit-switched network. Such capabilities are referred to as Carrier-Class capabilities.

Carrier Ethernet is poised to be a dominant technology of choice for next generation Metro Networks, and has already gained much traction. However, the standards for Carrier Ethernet, such as those referred to by the Metro Ethernet Forum, are still evolving and are not yet complete. More specification work needs to be done on topics such as Performance Monitoring OAM, Mobile Backhaul, and requirements for Ethernet Synchronization.

1 XG-PON is expected to be backwards compatible with the current generation GPON. Another ITU-T PON standard is being developed in parallel, ITU-T FSAN NGA2, which is more future looking and will not be compatible with the GPON standard. This version will support rates up to 40 Gbps and the standards is not expected to be completed until around 2015.