TECHNOLOGY IN CONTEXT
Cutting Edge Blades in Comm
ATCA Blade Choices Expand for Communications
ATCA offers greater board real estate and power compared to CompactPCI or PCI. Boards that take advantage of that are now coming to market.
MIKE COWARD, CONTINUOUS COMPUTING
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AdvancedTCA, the Advanced Telecom Computing Architecture specification from PICMG, promises the ability to quickly implement telecom applications using a variety of off-the-shelf components. The ATCA standard is starting to be embraced by leading telecom equipment manufacturers because it can be used to create high-capacity systems such as softswitches and media gateways, as well as wireless nodes including Gateway GPRS Support Nodes (GGSN), Serving GPRS Support Nodes (SGSN) and Radio Network Controllers (RNC).
As compared to existing industrial computing specifications like CompactPCI, AdvancedTCA offers blades with higher power, additional real estate and increased backplane bandwidth. As ATCA matures in the marketplace, a wave of blades are becoming available that demonstrate how this promise is being realized. Table 1 illustrates the evolution from CompactPCI to ATCA and compares the performance available from a variety of commercial off-the-shelf blades. The substantial improvement in processing performance, throughput and channel density is apparent. The primary ATCA blade board categories can be divided into three areas: high-density computing, high-density DSP, packet processing and switching.
The Intel Low Voltage Xeon processors are well suited to being implemented in AdvancedTCA. With a thermal design power specification of 55W, a dual processor design with memory, system I/O and mezzanine expansion fits nicely into the 200W budget that ATCA supports. This level of processing power is a significant increase over what has been possible on a CompactPCI blade, which generally can only handle up to 50-60W.
An example of a dual Xeon implementation is the ADLINK ATCA-6890 (Figure 1). Much of the board is dedicated to the processors and their heat sink, but the board is still able to provide two mezzanine sites to enable expansion and storage capabilities. The ATCA-6890 provides high-bandwidth connectivity to the backplane with six Gbit Ethernet ports supported.
Many telecom applications use in-memory databases or large caches in order to boost performance and meet transaction rate requirements. The blade supports up to 16 Gbytes of memory, four times the amount supported on CompactPCI, allowing up to 192 Gbytes of memory to be supported in a single ATCA shelf.
High-Density Digital Systems Processing
Many media applications require high channel density Digital Signal Processing (DSP), and ATCA provides an excellent vehicle to host these DSPs. The Continuous Computing DSPblade TI320 blade (Figure 2) supports 32 of the latest Texas Instruments C6415 DSPs at up to 1 GHz. The DSPblade delivers 256 GigaMACs of processing power and includes a high-performance network processor/control plane processor to terminate the fabric connection and distribute traffic to the DSPs.
AdvancedTCA provides enough printed circuit board real estate and power to allow the blade to support 32 DSPs, the packet processor and two mezzanine sites to terminate telephony interfaces like T1/E1, DS-3 and OC-3. As a result, DSPblade can support up to 12,000 media channels enabling extremely high-density systems to be designed and deployed.
The Intel IXP2850 processor provides high-performance packet processing with integrated security coprocessing. The IXP2850 includes 16 multi-threaded micro-engines for packet processing and an Intel XScale processor for control place functions.
The Continuous Computing PACKETblade IX20 packet processor blade supports dual IXP2850 processors to provide 10 Gbit/s line rate packet handling capabilities, and can terminate an OC-192, 10 Gbit Ethernet or multiple OC-12 connections into the backplane. The PACKETblade includes a fabric module allowing support for PICMG 3.1, 3.4, 3.5 or proprietary fabric technologies.
PACKETblade is well suited to wireless applications such as RNC, Node B, SGSN or GGSN. Wireless ATM links can be terminated onto the blade, and the framing protocols required for these wireless applications can be easily implemented on the microengines. Finally, the control plane protocols can be run on the XScale, allowing a complete single blade solution.
Most ATCA systems are designed around a pair of high-density fabric switches configured in a dual star architecture. The space and power budget of ATCA, combined with the latest switching silicon, allows the Continuous Computing COREblade FM10 to provide 48 Gbit Ethernet ports and up to five 10 Gbit Ethernet ports. COREblade (Figure 3) is the first AdvancedTCA switch to support two Gbit Ethernet fabric connections to each slot, allowing high-bandwidth applications such as video media servers and voice media gateways to be implemented.
COREblade also supports an Intel Pentium M processor to provide system management or application processing, as well as removable storage. This increases system density by eliminating separate system management blades. COREblade is a good example of the type of architecture innovation now available using ATCA, which would not have been feasible with earlier industrial computing specifications.
System Architecture Examples
It may be helpful to step back and discuss a complete system in order to fully demonstrate the overall advantages of ATCA. The system below shows how next-generation ATCA cards may be combined to build a next-generation combined media gateway and softswitch with terabytes of integrated storage. The system combines multiple Voice over Internet Protocol (VoIP) functions with 1+1 redundant application blades for each function, yielding vast functionality and flexibility for critical, carrier-class network applications.
In this configuration, the DSP blades each terminate dual OC-3 connections, allowing 4,000 channels to be handled per blade. The Dual Xeon CPU cards are used for the softswitch, announcement server and application servers, and the three terabytes of integrated storage are used for voice or video mail. Figure 4 shows an example of an integrated VoIP platform.
AdvancedTCA provides the essential platform foundation for enabling the delivery of high-density, high-performance applications within advanced telecom networks. By incorporating the latest trends in high-speed interconnect technologies and supporting higher power, additional real estate and increased backplane bandwidth, ATCA enables significant advantages in terms of processing performance, throughput and channel density. The resulting communications blade possibilities will lead to the next wave of innovation for end-user services in the converged communications network.
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