Transforming the IMS network infrastructure

The story is an ongoing saga. Telecom Equipment Manufacturers (TEMs) are continually on the hunt for better economies of scale and faster time-to-revenue when rolling out new network solutions. Market forces, however, are changing this in a big way. It’s called open standard modular communication platforms and it is giving TEMs a major leg up in accelerating roadmap implementations.

What’s the open standard?

AdvancedTCA is a fast emerging model for carrier-grade systems to be built on standardized hardware as defined by PICMG. More than 100 companies with very strong support from Intel have made this standard become a reality.

AMC extends the value of AdvancedTCA at the mezzanine level. And as a hot-swappable, Field Replaceable Unit (FRU), the AMC module opens up a whole host of design opportunities and can be used for any number of processing and I/O line card applications. AMC modules communicate via high-performance serial interconnects such as Gigabit Ethernet and PCI Express (PCIe) and may be designed with an AMC everywhere approach, where AMCs and AdvancedTCA boards such as AdvancedTCA carrier boards, CPU, and hub boards combine to create a powerful tool for designing new platforms.

The first version of this AMC specification has already been ratified, with additional iterations soon to follow for various types of connections. AMC supports 21 lanes of serial data traffic, which can be mapped to ports on the backplane. One lane is made of one differential pair in each direction (Tx and Rx).

The ancillary benefits from this cannot be ignored:

  • Easy manageability through IPMI
  • High Availability
  • Low power ultra dense processing
  • Lower operating costs
  • Most significantly, equipment consolidation that dramatically reduces the need for real estate by combining applications for content, billing, and transport

With the current growth in the wireless market, AdvancedTCA/AMC has quickly become an interesting answer to port new network elements away from costly proprietary platforms. Nearly the full spectrum of the wireless infrastructure is affected - from radio network controllers (RNC) and Gateway GPRS Support Nodes (xGSN) to Mobile Station Controller (MSCs) and HLR servers.

Another exciting area for AdvancedTCA/AMC is the range of application and multimedia servers used for IMS networks. As this market segment matures, many of its infrastructure challenges can be overcome with open modular platforms.

IMS infrastructure and business challenges

Carriers are expecting to increase revenue with multimedia applications, with new protocols and with services such as MBMS (Multimedia Broadcast Multicast Services), MMS (Multimedia Messaging Services), and PSS (Packet Switched Streaming) already opening doors for new applications.

To implement this, however, an increasing number of resources are needed for continual network deployment, keeping both CAPEX and OPEX costs too high, and placing a severe burden to be first on the market with new services. This first-come-first-serve scenario is what is driving TEMs to meet these new business requirements, as the industry moves towards an all IP infrastructure for next generation networks.

Today, each service requires its own separate platform, which is costly and often translates into interoperability and OS issues. Maintaining any level of redundancy requires additional platforms for load balancing, and as the number of new platforms increases so does the complexity with respect to manageability (OAM&P). Plus, there is always the risk of loss of revenue during periods of maintenance as more server elements are deployed. The less real estate available, the more carriers face the risk of giving up one service to make room for another.

Porting AdvancedTCA/AMC to IMS network elements

Figure 1 shows a sample configuration of an IMS multimedia network ported onto an AdvancedTCA/AMC platform. Further redundancy can be addressed by duplicating cards 1-6 on one chassis and cards 9-14 on a second chassis, connecting the chassis via a GbE interface. As the OSS and BSS are SNMP complaint, AdvancedTCA-built platforms also need to be SNMP compliant in order to support these multimedia services, which communicate to the DRM (Digital Rights Management) application within the network. This applies as well to user interactions for MBMS applications with Home Subscriber Service (HSS). The four typical interfaces required in the IMS network are:

  • GbE, which interfaces with the IP-based network infrastructure
  • SAN interfaces for content storage and HLR and VLR information
  • Processing interfaces for encoding/decoding/transcoding (DSP)
  • ATM and TDM transporting network interfaces

The multimedia service options for cellular subscribers are numerous, built on server-to-user, user-to-user, or multi-user applications. In light of the traditional network deployment of dedicated servers per application, now TEMs can offer advanced equipment that consolidates the various content, billing, and transport applications on far fewer platforms.

Figure 1 - Sample configuration of IMS multimedia network element ported onto an AdvancedTCA/AdvancedMC platform. Further redundancy can be addressed by duplicating cards 1-6 on one chassis, and cards 9-14 duplicated on a second chassis. Both chassis would be connected via a GbE interface.

For example, a 12U AdvancedTCA chassis that features 14 server board slots may be configured to support any combination of applications such as streaming audio/video (PSS, MMS, MBMS), SMS, DRM for digital rights management, security/firewall, billing, ringtone, and mobile gaming applications, and transcoding (interoperability compliance of any file format to any file format, such as AMR, AMR-WB, AMR-WB+, AAC, AAC+, VMR-WB Codec, MPEG-4, MPEG-2, and JPEG).

This is also where an open modular AdvancedTCA/AMC system is ideal for storing multimedia content. As hard drives could be made to fit on an AMC, each module could hold 80 GB at the very least, which gives a capacity of over 5 Terabytes on only one AdvancedTCA chassis. In order to deliver the content, multiple challenges are being faced within the delivery method. With the wide range of 3G handset manufacturers, a wide range of protocols and standards need to be supported. Interoperability plays an important role in the deployment of the 3G infrastructure not only for basic telephony functions such as the transcoding function for speech, but also for encoding and decoding, VAD/DTX, and echo cancellation in the Base Station Transceiver System (BTS).

Content (audio, video, pictures) can be encoded in various different formats supported by the SIP and H.323 network infrastructure and may be stored in the SAN over several different networks. Content transcoding is an important part of the puzzle for the deployment of next generation services and requires high processing resources (MIPS) for quality operation.

Further configurations may support VoIP applications (SIP, H.323, MGCP), Voice Mail, IVR, Mobile commerce, Push To Talk (PTT), and Video on Demand (VoD) services.

Faster ROI, reduced OPEX, and more service innovation

Ultimately, for any carrier, or wireless, wireline, or cable provider, the high return on investment becomes immediately clear when the platform real estate required for all these applications is essentially reduced by two-thirds in comparison to deploying the same applications on single, dedicated platforms.

Depending on the application being deployed, TEMs can expect to go to market twice as fast with a significant reduction in CAPEX and OPEX costs, with the latter being weighed the most by carriers. TEMs are in a position to demonstrate that any amount of CAPEX will mean a significant amount of savings during a very short period of time. Subsequently, ROI is virtually immediate. This allows carriers to invest in open platforms with a long-term IMS strategy for growth, which will support completely seamless adaptability at the networking equipment level for years.

Sven Freudenfeld is responsible for North American Business Development for the Kontron line of AdvancedTCA and AdvancedMC modular solutions. Sven possesses more than 15 years experience with voice, data, and wireless communications, having worked extensively with Nortel Networks, Sanmina-SCI, and Deutsche Telekom.

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