How one TEM leverages ATCA Hardware Platform Management

3Nokia Siemens Networks (NSN) has made a strategic choice to take maximum advantage of the open architecture benefits of AdvancedTCA (ATCA) for its product offerings. ATCA's hardware platform management architecture is a critical part of those benefits and crucial to NSN and its customers.

Numerous benefits result from using ATCA for NSN’s Open Core System (the foundation of NSN’s ATCA-based products). Overall, the footprint of the hardware can be up to 80 percent smaller and energy consumption up to 40 percent less compared to previous products. At one NSN customer, for example, two racks of existing equipment were replaced by a single ATCA shelf implementing a Mobile Softswitch Solution (MSS). Figure 1 shows how the functionality of a full core network site can be implemented in two ATCA racks.

Figure 1: An example of a core network site in two ATCA racks.

One contributor to both reductions is that the number of plug-in boards can be reduced by up to 80 percent because of the good density that ATCA enables. In addition, the number of distinct board types is reduced because the boards are applicable to many different purposes, which translates to bigger volumes and reduced cost.

There are two main board types used in all NSN ATCA applications: the CPU blade (x86 server blade), and the HUB blade (Ethernet switching). In addition, there are specialized blades for specific gateway types, including:

  • Multicore Packet Processing (MPP) blade
  • Digital Signal Processing (DSP) blade
  • AMC Carrier blade (carrier for network interface AMCs)

The MPP blades, for example, can handle both the user plane implementation up to level 4 and the control plane implementation flexibly within the same COTS blade, for which there are multiple competing vendors around the world. Some non-ATCA solutions, in contrast (such as those based primarily on ASIC-intensive router technology) have specialized proprietary hardware to address the same functionality and cannot evolve as quickly or take advantage of the worldwide, competitive COTS blade market.

ATCA’s Hardware Platform Management (HPM) in
NSN strategy

The NSN ATCA strategy has two key aspects dependent on HPM:

  • Aggressive incorporation of successive generations of COTS ATCA blades and AMC modules, with each multi-vendor generation representing the best-in-class offering of the ATCA ecosystem for each functional area. This gives NSN customers a unique possibility to amortize their ATCA investment over a long period by introducing latest generation boards with rhythms appropriate to the changes and growth of their networks.
  • Software platforms isolate network application software from hardware. From an application point of view, this separation enables developers to focus on the applications without being distracted by hardware bring ups or other High Availability (HA) and carrier-grade features offered by foundation software platforms. In fact, these software platforms even span the differences between NSN’s pre-ATCA equipment and the current ATCA-based equipment. This allows optimal software reusability from existing mature applications, as hardware and higher level application layers are not dependent on each other.

The time-to-market for COTS ATCA blades and AMC modules can be very short; this enables NSN to provide quick access for its customers to the latest generation of silicon. Quick introduction of new silicon also maximizes the effective board and module lifecycle. NSN’s customers can at the same time benefit from state-of-the-art technology, and cost-effective investments, as these boards and modules are not already outdated when delivered to end customers.

In addition, standard HPM helps to ensure upgradeability over ATCA board generations. Operators don’t need to replace the existing network elements when requiring more capacity over the years. Only updates of payload boards and modules are required. Consider, for example, the third and fourth generations of NSN’s ATCA architecture, which are mainly distinguished by the fact that the fourth generation supports 40 G capacity on its in-shelf networks. In the third generation, NSN included a 40 G-capable backplane. Therefore, upgrades to the fourth generation only require replacing the 40 G hub boards and any other boards that need to communicate at 40 G. 10 G-focused boards do not need to be replaced because the 40 G hub boards are backward-compatible with 10 G.

Implementations of the ATCA HPM layer have continued to mature over the four generations of NSN’s ATCA products. At the blade and module level, our experience confirms a significant advantage in basing the mandatory local controllers on COTS implementations that benefit from widespread implementation and mature interoperability characteristics. At the shelf level NSN has been well served through all four generations by the same widely used and stable COTS Shelf Manager.

The Service Availability Forum’s (SAF’s) Hardware Platform Interface (HPI) plays a key role in achieving a well-managed layer between the hardware and software platforms. HPI hides the complexity of ATCA’s internal IPMI structures and makes it possible to define an Application Programming Interface (API) between the hardware and software platforms. In systems with hardware building blocks from various sources, HPI’s role is essential. Without HPI, ATCA system integration would not be as successful as it is now.

Specifically, as Figure 2 shows, the hardware independence of HPI allows the software platform, which represents massive TEM and/or TEM customer investments, to be used with multiple generations of hardware, including both ATCA and pre-ATCA hardware. For the pre-ATCA hardware, an open source implementation of HPI called OpenHPI can be used, leveraging its plug-in architecture to cover multiple hardware platform variants. For our ATCA hardware, the Shelf Manager has a built-in IntegralHPI, which supports the same client interface as OpenHPI, extending HPI’s portability across multiple ATCA generations as well.

Figure 2: HPI enables a software platform that is largely independent of the hardware platform.

The achievement of software independence across the previous non-ATCA and current ATCA equipment benefits from the fact that the hardware management layer for the earlier NSN equipment is based, like ATCA’s, on the Intelligent Platform Management Interface (IPMI) in a CompactPCI context. In fact, NSN’s deep experience with HPM-enabled CompactPCI equipment was a contributing factor when the HPM strategy for ATCA was chosen a decade ago.

Customer reception of NSN’s ATCA products

NSN’s currently released ATCA portfolio covers a wide variety of applications, ranging from voice core to high-end LTE packet core products. By the end of 2012, NSN expects to have more than 10 different applications utilizing the same hardware base. With ATCA, NSN and our customers gain the scalability and versatility needed for building up multipurpose hardware installations. NSN customers have been especially pleased with the performance, scalability, and payback time of ATCA hardware. NSN’s ATCA-based Open Core system is in use today around the world. Installations supporting hundreds of thousands of subscribers are seeing strong growth in the number of live networks and continuing subscribers.

Improvements in ATCA HPM: A TEM’s take

The HPM facilities of ATCA are working well for NSN’s ATCA-based products. NSN is counting on further improvements in this layer as it continues to ramp up the sophistication and reach of its ATCA offerings. The HPM.2 specification (for LAN-attached IPM Controllers (IPMCs)) that is nearing completion in the PICMG HPM.x subcommittee should enable the use of backplane Ethernet connections to IPMCs as a supplement to the current mandatory I2C-based backplane connections. Such connections could drastically (by as much as a factor of 10 or more) speed up firmware upgrades, for example.

The 1 Gbps Ethernet Base Interface already reaches every ATCA blade, and AMC carrier blades typically provide similar fabric to their AMCs. This is a huge step up from 100 Kbps IPM Buses (IPMBs), especially for large firmware upgrade images, even if the IPMC links to networks that run no faster than 100 Mbps. With comprehensive implementation of the HPM.2 specification in next-generation ATCA platforms, faster speeds could benefit not only firmware upgrades, but other areas of ATCA performance as well. For instance, complicated ATCA configurations take substantial time to power up due to voluminous configuration information that must be retrieved from the shelf blades and modules. Comprehensive use of Ethernet-based paths for this retrieval could dramatically reduce startup times.

HPM.2 implementation is on the path to the post-ATCA open platforms sketched by the SCOPE Alliance, which includes all Tier1 TEMs. SCOPE recommends the future platform architecture (targeted to span 2015-2025) reuse ATCA HPM with extensions, replacing the main IPMB with at least 100 Mbps Ethernet.

Jari Ruohonen is Head of Core Platform HW Product Management and ATCA Product Line Manager at NSN.

Nokia Siemens Networks (NSN) |