In our last series of tutorials, we examined the architecture and components of softswitches, including the standards that they are designed from, and the protocols that are used for communication between the various softswitch elements.
Part I: Getting there from here
Part II: Functional planes of the softswitch architecture
Part III: The Media Gateway Controller
Part IV: Media Gateway architecture
Part V: Media Gateway Control Protocol
Part VI: MEGACO/H.248 Protocol
Part VII: IP Multimedia Subsystem
Part VIII: IP Multimedia Subsystem functions
With this tutorial we begin a series of reviews of various vendors softswitch architectures, examining how their systems correspond with the softswitch standards and protocols that we have previously studied. We will begin with the product line from Avaya.
Avaya Inc., headquartered in Basking Ridge, New Jersey, was spun off from Lucent Technologies, Inc. in October 2000. Going back further in Avayas lineage, we find Lucent parents AT&T and Bell Telephone Laboratories, which includes a century-old history of circuit switching, but also rich heritage of research and patents in voice communication. To find Avaya as a significant player in the packet switched and VoIP world is therefore a testimony to their agility to reconfigure both their thinking and their inherited product lines into a new way of doing business. And from all accounts of market share penetration, they are doing quite well in both categories.
Avayas business is focused in four strategic, yet inter-related areas: IP Telephony, Contact Centers, Mobility, and Services. Their IP Telephony product line, which is the most relevant to our discussion, consists of three key components: the Communication Manager Software, plus the supporting Media Servers and Media Gateways.
Communication Manager 3.0, released in June 2005, integrates a number of telephony functions, including call processing and control, messaging, contact center, and an application programming interface into a system that supports both circuit-switched and IP telephony. Two editions of the software are available: an Enterprise Edition, for multi-site configurations, and a Standard Edition. This software is considered the centerpiece of Avayas Multivantage communications applications portfolio, and can scale from under 100 users to as many as 36,000 users on a single system, or to more than 1,000,000 users on a single network. The software is designed to run on a variety of Avayas Media Servers, including the DEFINITY server, or a number of the Media Servers that utilize the Linux operating system.
This most recent software release includes a number of features designed to enhance the survivability and reliability of the enterprise network. The Enterprise Survivable Server (ESS) feature, which is included in the Enterprise Edition, resides on the main server, and allows an ESS server at a branch office to take over in the event of a communications failure at the headquarters location. Another interesting enhancement is the Inter-Gateway Alternate Routing, or IGAR, which provides a means to send traffic to the Public Switched Telephone Network (PSTN) if the IP network is presently incapable of carrying the required traffic. In addition, the SIP Enablement Services allow the integration of multivendor telephony networks, with support for analog, digital, H.323, and SIP endpoints.
Avaya Media Gateways are stackable, modular units that contain the network and endpoint interfaces. A number of media gateways are available, designed in a wide array of sizes, starting with very small (2-15 seat) branch offices, with support for the H.248 protocol available. A number of LAN and WAN interfaces are also supported, including the typical Ethernet for LANs and T-1 for WANs, with the addition of DSL, cable modem, and Power over Ethernet (PoE) for more unique applications. Modem dial backup and cable modem backup are also available for greater network reliability and survivability.
Further details on the Avaya architecture and products can be found at www.avaya.com. Our next tutorial will continue our examination of vendors softswitch architectures.
Copyright Acknowledgement: © 2005 DigiNet ® Corporation, All Rights Reserved
Mark A. Miller, P.E. is President of DigiNet ® Corporation, a Denver-based consulting engineering firm. He is the author of many books on networking technologies, including Voice over IP Technologies, and Internet Technologies Handbook, both published by John Wiley & Sons.