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By Rich Pellegrini, Product Marketing, NMS Communications
The follow article is an excerpt from the NMS white paper, Economics of Five-Nines Systems: CompactPCI vs. AdvancedTCA. The complete paper contains a cost comparison of the various examples given in this article, as well as a discussion of the operational and opportunity cost of service failures and downtime.
An important attribute of any system that provides a critical communications or transaction-based service is that it be highly available (HA), from both a user perspective and a system perspective. Examples of communications systems in this space include telecom value-added services such as conferencing, wireless music services, and voice and video portals, for which an interruption in service can mean lost revenue.
Attributes of Five-Nines HA Systems
The overall “availability” of a service is determined by both how often outages occur and how long it takes to recover from them. The goal is to design a system such that outages occur infrequently, and when they do occur, they can be identified and repaired quickly. For telecom and transaction-based monetary systems with advertised high availability, service is guaranteed not just 99 percent of the time, but 99.999 percent of the time, or with five-nines availability. This translates into about five minutes and fifteen seconds of downtime per year—or virtually continuous uptime.
Commercially Available Technologies for use in HA System Designs
A HA telecom system can be developed using both rackmount servers and blade servers.
Rackmount Servers
Rackmount servers are turnkey computing chassis/enclosures, often in 1U or 2U form factors, that include processors, memory, disk drives, power, cooling fans, networking interfaces, and chassis management. All computing components are on a single motherboard, with limited expansion slots for specialized peripherals. Rackmount servers are offered in both redundant and non-redundant models.
Blade Servers
Blade servers provide basic hardware, such as power, cooling fans, chassis management, and backplane signal distribution, in a base rackmount chassis. Processing, storage, and interface functionality is available in the form of plug-in cards or “blades.” Blade servers are offered in standards-based form factors, like PICMG-compliant cPCI or ATCA, and proprietary form factors, such as those offered by Dell, IBM or HP (HP also offers standards-based blade servers).
The focus of this article is on developing HA systems using standards-based cPCI and ATCA blade servers.
Building a High Availability System
When considering current cPCI product offerings, there are two generations to consider—the base PICMG 2.0 generation and the later cPCI Packet-Switched Backplane (cPSB) PICMG 2.16 generation. (Refer to the complete white paper for a detailed discussion of the attributes of the PICMG 2.0 and 2.16 specifications.)
PICMG 2.0 Example
Fully redundant systems built with PICMG 2.0 generation cPCI equipment consist of a split backplane chassis with two distinct PCI bus domains representing a cluster in a box. This architecture implements a full 2N system redundancy with up to seven peripheral boards per node, as two redundant host SBCs interact to determine their active or standby role. External digital cross-connect equipment would be required to switch between the telecom interfaces of the active or standby cluster for telecommunications-based systems. A redundant system with this description is shown in Figure 1.
Figure 1: PICMG 2.0 Generation Chassis Example
Assuming a 2000-port interactive voice response (IVR) telephony system constructed with 480-port telephony boards, five telephony boards would be required for each redundant cluster, for a total of ten boards, stranding 2000+ ports of capacity.
PICMG 2.16 Example
Redundant systems built with PICMG 2.16 generation cPCI equipment consist of a redundant host chassis with two bridgeable PCI bus domains, representing a dual-host single system with up to fourteen peripheral boards. Two redundant host SBCs interact to determine their active or standby role. The active SBC utilizes a PCI bridge card to gain control of the second PCI bus segment. The standby SBC has no PCI bus control until it is required to become the active system controller. A redundant system with this description is shown in Figure 2. Note the IPMI bus is omitted in the diagram to show other components.
Figure 2: PICMG 2.16 Generation Chassis Example (with legacy PCI Bus, Redundant Host Configuration)
Assuming the same 2,000-port telephony system constructed with 480-port telephony boards, only six telephony boards would be required to meet the required density, regardless of which host was the active chassis controller. Because the telecom interface boards are a pooled resource in this case, an N+1 redundancy architecture is employed, allowing the host to swap in a spare resource for a failed one.
Autonomous PICMG 2.16 Example
|
AUTONOMOUS OPERATION
The dictionary definition of “autonomous” implies totally independent operation. But “autonomous” used in the context of PICMG 2.16 and ATCA means that the device can be controlled remotely through IP (Start, Stop, Query) and it is not dependent on a computing bus within the chassis. |
Redundant systems built with purely autonomous PICMG 2.16 generation equipment would consist of a non-PCI, fully packet-switched backplane chassis with two redundant SBC system hosts, two Gigabit Ethernet fabric switches, and up to sixteen peripheral/processor boards. The two redundant host SBCs would interact to determine their active or standby role and would communicate with the autonomous telecom blades using an Ethernet-based control protocol. There is no PCI bus in the chassis, so no bus arbitration or bridge hardware is required. A redundant system with this description is illustrated in Figure 3.
Figure 3: PICMG 2.16 Generation Chassis Example (pure Autonomous Blade Server with Redundant Host Configuration)
Assuming the same 2,000-port telephony system constructed with 480-port telephony blades, only six autonomous telephony blades would be required in order to provide an N+1 redundant telecom interface architecture, regardless of which host was the active chassis controller.
AdvancedTCA Example
ATCA defined by the PICMG 3.x series of specifications represents the third generation of standards-based carrier-grade platform hardware. This specification set builds on the HA improvements of the PICMG 2.16 hardware generation by improving chassis management, redundant, modularity, blade size, and power allotment. (Refer to the complete white paper for a detailed discussion of the attributes of the AdvancedTCA specifications.)
Redundant systems built with purely autonomous ATCA generation equipment would consist of a dual-Gigabit Ethernet, fully packet-switched backplane chassis with two redundant SBC system hosts, two Gigabit Ethernet dual fabric switches, and up to ten peripheral/processor blades. Note, the increased blade width allows for fewer peripheral node blades than an equivalent 19-inch rackmount PICMG 2.16 generation chassis. The two redundant host SBCs would interact to determine their active or standby role and would communicate with the autonomous telecom blades using an Ethernet-based control protocol. An ATCA redundant system with this description is shown in Figure 4.
Figure 4: ATCA Generation Chassis Example (pure Autonomous Blade System with Redundant Host Configuration)
Although the larger blade size of the ATCA form factor allows for higher density telecom interface hardware, service providers and HA system designers must ensure the loss of a single resource does not provide a service interruption to more than a certain percentage of subscribers.
Assuming the same 2,000-port telephony system constructed with 480-port telephony blades, in order to minimize the number of ports impacted during a blade failure, six autonomous telephony blades would be required for an N+1 redundancy telecom interface architecture, regardless of which host was the active chassis controller.
The Cost of High Availability
While the cost of creating HA systems using cPCI and ATCA vary (see the complete white paper for details), more than just the equipment cost must be considered when making a choice between cPCI and ATCA. Other items include the cost of:
- Service monitoring and maintenance personnel
- Platform software system upgrades (patch and version upgrades)
- Repair personnel and associated logistics required to perform a hardware maintenance action (including problem debugging cost depending on the number of levels of support required to be engaged based on the fault reporting and logging/debugging capabilities of the platform)
- Operational and opportunity loss due to service failures and downtime
The costs associated with service downtime can include lost revenue, decline in customer satisfaction, loss of a customer to the competition (which is an easier decision with the advent of local number portability), and even damage to reputation via bad publicity (press or blog/message board) or word of mouth.
Developers of live, revenue generating services who require high availability must choose platform standards and designs that provide numerous and well-planned HA features. ATCA includes a number of HA features that eliminate single points of failure and allow system developers to truly reach five-nines available systems with reduced time-to-market and development costs.
Although not the final word in HA platforms, a concerted effort should be made by service providers and telecom equipment manufacturers to require ATCA platforms, and by solution providers to transition to ATCA platforms, in order to reduce operating costs by taking advantage of the improved HA features it offers.
In the February 2007 issue of Telecom Innovators News, NMS provided details on the discontinuation of the AG 4040 and AG 4040C (as well as CG 6500C). These products will be discontinued by the end of this year, according to the schedule in Table 1.
|
Event |
Date |
|
Last Order Date |
28 September 2007 |
|
Last Ship Date |
28 December 2007 |
Table 1: Product Discontinuation for the CG 6500C, AG 4040, and AG 4040C
The suggested replacements for the AG 4040 products are described in Table 2. Refer to the article in the February newsletter for information on the CG 6500C replacements.
|
Part No. |
Existing Model |
Part No. |
Replacement Model |
|
Existing Board |
AG 4040 |
Replacement board |
CG 6060 |
|
82100 |
AG 4040/4-1TE |
82926 |
CG 6060/11-2L/1TE |
|
82101 |
AG 4040/8-2TE |
82383 |
CG 6060/11-2L/2TE |
|
82102 |
AG 4040/16-2TE |
82911 |
CG 6060/16-2L/2TE |
|
82103 |
AG 4040/16-4TE |
82384 |
CG 6060/16-2L/4TE |
|
82104 |
AG 4040/32-4TE |
82385 |
CG 6060/32-2L/4TE |
|
82114 |
AG 4040/40- 4TE |
82387 |
CG 6060/42-2L/4TE |
|
Existing Board |
AG 4040C |
Replacement board |
CG 6060C |
|
82107 |
AG 4040C/16-4TE |
82388 |
CG 6060C/16-2L/4TE |
|
82108 |
AG 4040C/32-4TE |
82389 |
CG 6060C/32-2L/4TE |
Table 2: Discontinued AG 4040(C) Products and Suggested Replacements
Key Hardware Differences
Table 3 describes key hardware differences between AG 4040 and CG 6060 boards.
|
Item |
AG 4040(C) board |
CG 6060(C) board |
|
Connections |
Limited to 256 simple connections on the H.100/H.110 bus |
Simultaneously connect (simplex) to all 4,096 timeslots on the H.100/H.110 bus |
|
DSPs |
C549 DSP (dual core)
Maximum 40 cores, 4,000 MIPS |
C5441 DSP (quad core)
Maximum 32 cores, 4,256 MIPS |
|
E1 impedance |
E1 impedance default is 120Ω, but switch selectable to 75Ω |
E1 impedance is software configurable to 75Ω, 100Ω, 120Ω, or HiZ |
|
Echo cancellation |
Software echo cancellation |
NMS proprietary echo cancellation chip; software echo cancellation available |
|
Ethernet |
No Ethernet connectivity |
Dual 10/100Base-T (VoIP support) |
|
Power requirements(max) |
AG 4040 w/ daughterboard: 2.2A @ 5.0V; 3.0A @ 3.3 V
AG 4040C w/ daughterboard: 2.2A @ 5.0V; 3.0A @ 3.3 V |
CG 6060: 1.5A @ 3.3V; 1.2A @ 5.0V
CG 6060C: 3.8A @ 3.3V; 1.1A @ 5.0V |
|
Trunk interface jacks |
PCI: 1, 2, or 4 RJ-48Cs (1, 2, or 4 trunks)
cPCI: 4 RJ-48Cs(4 trunks) |
PCI: 1 or 2 RJ-48Cs, or 2 RJ-45s (RJ-45s require splitter cable)(1, 2, or 4 trunks)
cPCI: 4 or 8 RJ-48Cs or 1 or 2 RJ-21s (4, 8 or 16 trunks) |
Table 3: Key hardware differences between AG 4040 and CG 6060
Key Software Differences
Key software differences between the AG 4040(C) and CG 6060(C) include:
- The AG 4040(C) has been supported since NA 2004-1. The most current version of Natural Access is NA 2005-1 Service Pack 3. You will need to recompile the application with NA 2005-1 SP3 (or later) libraries and header files
- There are changes to the product name in the board configuration files. You will have to use the CG 6060 board keyword files instead of the AG 4040 board keyword file
- There are differences in DSP configuration and resource allocations. DSP resources for the CG boards are allocated using a Resource Manager.
- The CG 6060(C) has additional configuration sections for IP address, routes, etc.
- There will be configuration changes if you want to use the hardware echo cancellation
- You can add VoIP and/or video capabilities with the VoIP service (Fusion) included in Natural Access and with the optional Video Access toolkit
Details on all the hardware, software, configuration, and other differences can be found in the AG 4040/C to CG 6060/C Migration Manual on the NMS web site (available in the documentations listings under all NA 2005-1 SP3 downloads: )
Contact your NMS sales representative if you have any questions or require additional information regarding the AG 4040(C) product discontinuation or migration.
By Dan Kozin, Director, Product Management, Vision Server Products
The World Wide Web Consortium (W3C) defines Call Control eXtensible Markup language (CCXML) as a developing standard for managing and supporting telephony call control with a VoiceXML-based application. While it is designed to be used with any media capable dialog application, CCXML’s key benefit is the ability to complement and integrate with VoiceXML to setup, monitor, and tear down phone calls.
Because VoiceXML was designed to support a simple transactional-based single-threaded programming model and telephony call control requires a more complicated asynchronous event handling model, a different standard was needed. CCXML was created to support an event-based model that could receive and respond to multiple asynchronous events while being compatible with VoiceXML.
VoiceXML was designed for media presentation in a call, it uses a linear approach. This model works well within user-interface-supplied commands, but does not provide an easy way to operate outside a pre-determined set of options. For example, a call center application that intelligently gathers information from the caller, and then passes that information on to the call center agent before answering the call, benefits from CCXML by easing the information flow within the call.
With these two open standards, media application developers can leverage the strength of web platforms and technologies to intelligently control calls on and off the telephone network.
CCXML was designed with these goals in mind:
- Support for multi-party conferencing, with more advanced conference and audio control.
- Sophisticated multiple-call handling and control, including the ability to place outgoing calls at any time, initiated outside of the VoiceXML platform.
- Handling for richer and more asynchronous events. Advanced telephony operations involve substantial signaling, status events, and message-passing. VoiceXML does not currently have a way to integrate these asynchronous "external" events into its event-processing model.
- An ability to receive events and messages from systems outside of the CCXML or VoiceXML platform. Interaction with an outside call center platform, calls started asynchronously from the VoiceXML platform, and communication between multiple "clustered" VoiceXML or CCXML platforms all require event interaction from one XML platform to another.
CCXML provides the following functionality not possible with VoiceXML alone:
- Routing: Routes calls to the next available line in a group; or find me/follow me capability to track a person down at multiple possible locations.
- Bridging: Connects a call between two call legs.
- Outbound Calling: Initiates a call and starts one or more VoiceXML dialogs once a connection is established.
- Selective Call Answering: Decides whether or not to answer a call based upon caller information.
- Conferencing: Allows multiple participants to join a phone conference.
- Coaching: Allows a third party to connect to a call, but only have one of the participants hear what is said.
- Dialog Execution: New instances of VoiceXML interpreters can be created and destroyed at will.
Figure 5 shows how CCXML and VoiceXML work together (source: http://www.developer.com/voice/article.php/1565751):
Remember, CCXML is not a media/dialog language like VoiceXML. It only provides support to move calls around and connect them to dialog resources.
NMS has chosen to add CCXML 1.0 support in its next release of the Vision VoiceXML Server to provide a complete application-ready platform that can deliver interactive voice and video applications by using markup languages such as VoiceXML 2.0 and 2.1, and CCXML 1.0. NMS’s Vision VoiceXML Server provides operators and value-added solutions providers the ability to rapidly develop and deploy new and innovative voice and video applications for IP, PSTN, and 3G-324M networks. Applications that are well suited for VoiceXML and CCXML interpreters include voice and video messaging, speech enabled IVVR systems, and interactive entertainment.
Product News
Are you thinking about migrating your current offering to AdvancedTCA? Then test drive NMS’s ATCA media processing blade, the MG 7000A. The MG 7000A features a powerful combination of high-speed IP packet handling, four Gigabit Ethernet interfaces, high-density DSP voice media processing power, and optional T1/E1 interfaces.
To jump start your development efforts, NMS offers two MG 7000A Starter Kits, which come with a blade and technical support. Available today is a Starter Kit for the IP-only version of the MG 7000A. A Starter Kit featuring the TDM version of the MG 7000A, supporting up to 16 T1/E1/J1 connectors on a rear transition module, will be available in September.
Contact an NMS sales representative for additional information on either of these MG 7000A Starter Kits. Don’t know who to call — fill out this short inquiry form to have a NMS sales representative contact you.
Support Tip
The CG 6060 is NMS’s PCI platform for developing cost-effective, scalable, highly reliable telephony solutions. In order for the CG 6060 with single and dual T1/E1 interfaces to work properly, you must use NA 2005-1 SP3 and download and install patch #5953. Patch #5953 resolves an issue that prevented the Framer chip from initializing properly on the following models of the CG 6060;
|
Part Number |
Product Description |
|
82926 |
CG 6060/11-2L/1TE media processing board (1 RJ-48C) |
|
82383 |
CG 6060/11-2L/2TE media processing board (2 RJ-48Cs) |
|
82911 |
CG 6060/16-2L/2TE media processing board (2 RJ-48Cs) |
Table 4: CG 6060s with Single or Dual T1/E1 Interfaces
Download patch #5953 to resolve this issue
For additional support tips, visit Technical Notes.
Spotlight Events
NMS has created a web site specifically for our Connect 2007 conferences taking place this autumn in Boston (USA), Guilin (China) and Madrid (Spain). The micro site offers interest prospects and registrants information on each conference, the conference program, speaker bios, hotel and travel, special events, and sponsorship options.
Click here to access the Connect 2007 Web Site.
For those not familiar with our Connect events, they are a series of global conferences that target key business and technical decision makers who are interested in learning about the vital drivers shaping the communications ecosystem—the business issues, the market drivers, the technology challenges, the compelling applications, and the end user demands.
Last year, the Connect conferences were a great success, with numerous attendees, speakers, and NMS executives enjoying two days of discussion, networking, and fun! The events featured six high-powered panel sessions and attracted over 300 attendees from operator, application developer, and network equipment companies including: Alcatel, Avaya, Broadcom, Cingular Wireless, Crealog, Golden Dynamic, Kirusa, NEC, NTT DoCoMo, Reitek, Siemens, Sun Microsystems, Vodafone, and Voice Mobility.
NXTcomm 2007, taking place in Chicago at the McCormick Place Convention Center, is the global forum and marketplace for the new business of information, communications and entertainment technology.
NMS will be exhibiting in the PICMG booth, number 4257, where we will be featuring our high-availability solution, the MG 7000A AdvancedTCA media processing blade. As a member of PICMG, NMS has been a leader in technology innovation and standardization, including AdvancedTCA. NMS has been actively involved in the development of the specification and in subsequent industry interoperability events.
Exhibit Hall Passes
If you are interested in learning more about NMS’s MG 7000A AdvancedTCA media processing blade, featuring high-speed IP packet handling and high-density media processing power, and would like to meet at the show, click here to register for your free pass (a $150 value). Select the attendee option, enter “VIP7” in the passcode box, then click on “Register.” You will have to fill out a brief form to complete your registration. Offer expires June 17, 2007.
Exhibit Hours
Tuesday, June 19, 2007 10:00 am–5:00 pm
Wednesday, June 20, 2007 10:00 am–5:00 pm
Thursday, June 21, 2007 10:00 am–3:00 pm
Meeting Request
If you would like to schedule a meeting with a NMS sales representative, click here to fill out a short form. You may also call Janice Manning at +1 508 271 1355.
On May, 22, NMS hosted the web seminar “Connecting Your SIP-Based Hosted Contact Center to the Rest of the World,” with well-known industry speaker, Brough Turner, Senior Vice President and Chief Technical Officer at NMS Communications. In his presentation, Brough discussed how media and signaling gateway resources can be configured to address global connectivity for hosted enterprise contact centers, explained the problem and typical solutions, including SIP to ISUP signaling, and how they are adapted for different global conditions. Click here to access the archived recording and or PDF today!
On June 26, 2007, NMS will present the web seminar
“Mobile Video Made Easy”
Rising demand for mobile video services is creating major new revenue opportunities, both for network operators and for application developers. But mobile video is not a simple medium. Developers face stringent performance requirements, multiple interoperability issues, and a variety of other technical challenges. Fortunately, they do not have to face these challenges on their own. Advanced platforms and toolkits from industry leaders like NMS Communications shield developers from the technical complexities of mobile video and give them the leg-up they need to produce attractive, responsive, profitable applications quickly and cost-effectively.
Who should attend:
Product managers, systems architects and developers developing and deploying video based applications for fixed telecom and mobile environments.
Register now for this web seminar on June 26
7:00 AM EDT for Asia and Europe, Middle East,
and Africa 11:00 AM EDT for Americas |