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Volume 2 Number 4, Fourth Quarter 1996
Stratm Technology Improves Performance and Scalability of Broadband Networks
Today's Internet service providers (ISPs) are struggling to keep pace with exponential growth in traffic volumes and the advent of resource-hungry, time-sensitive multimedia applications. Millions of new users are jumping online every month, and every time a user clicks on a Web page, a new virtual connection must be established by the underlying switching system.
The burden of keeping up with these burgeoning traffic demands rests with the telecom carriers, ISPs, and large enterprise customers who are constructing the Internet's broadband networks. Many of these organizations are anticipating an Asynchronous Transfer Mode (ATM) switching solution that delivers the low response times and high throughput required to support explosive Internet growth.
"The Internet community needs a network platform that delivers exceptional scalability and functionality at a low cost," says Stan Kramer, Marketing Director of Cisco Systems' WAN Business Unit. "What's needed is an ATM platform that can support multiple classes of service, offer high levels of resilience, scale to support hundreds of thousands of user connections, and offer advanced capabilities such as traffic management, buffer management, and virtual circuit queuing."
Cisco is rising to the challenge with a new family of intelligent Broadband Switching Modules (BXMs) for the Cisco StrataCom® BPX Service Node that enables a fourfold improvement in performance and scalability. The BXM products are based on Cisco's StratmTM technology, a new approach to ATM switching that incorporates patented, standards-based Cisco technology into custom silicon. These application-specific integrated circuits (ASICs) dramatically increase ATM efficiency and scalability while significantly lowering the overall cost of delivering ATM solutions."Stratm is designed to take customers to the next level in building the most efficient and scalable ATM networks in the world," Kramer says. "It works by optimizing and distributing critical switch processing functions to individual DS3, OC-3, and OC-12 ATM line cards for the BPX."
For example, a single BPX switch equipped with Stratm technology can support 384,000 connections--scaling up to 768,000--with Weighted Fair Queuing for up to 64,000 virtual circuits at OC-12 rates. The Stratm modules rely on high-performance RISC chips to process up to 4000 calls per second through a distributed call-processing architecture.
| An Integrated Solution |
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| As part of Cisco's comprehensive ATM initiative, the StrataCom BPX system will support Cisco's newly announced Tag Switching technology and Cisco Internetwork Operating System (Cisco IOSTM) software, giving customers a highly integrated and seamless solution that brings together routing and switching on a single wide-area platform. For more information on Cisco's Tag Switching, see the 4th Quarter 1996 issue of PacketTM, "New Technology Fuses Routing and Switching for Scalable, High-Performance Networks."
"With the introduction of Tag Switching and integration of Stratm Technology in the BPX, Cisco is attempting to leap-frog the industry by delivering a massively scalable, full-function Internet platform," says Tom Nolle, President of CIMI Corporation, a telecommunications consultancy in Voorhees, New Jersey. "They are taking all of the most critical, processing-intensive ATM functions and optimizing them on high-performance ASICs. This will serve to drive up efficiency and drive down cost." |
Designed and developed by StrataCom prior to its acquisition by Cisco Systems, Stratm represents a two-year, US$10 million research and development effort. The technology is based on a scalable switching architecture that distributes advanced ATM functions-such as congestion management, virtual circuit queuing, class of service, and multicasting-to cards for faster, more efficient processing. This feature eliminates the possibility of a single point of failure disrupting the entire network.
Stratm distributes extensive buffering and advanced traffic control to line cards surrounding a simple high-speed switching fabric, improving the functionality, scalability, and cost effectiveness of broadband ATM networks. Cisco users and partners are hailing this approach for its breadth and flexibility: they can improve the capabilities of their existing switches simply by introducing new line cards, without obsoleting the switch fabric of older line cards.
"Embedding ATM functionality in silicon serves to stabilize the transport layer of the network, guaranteeing the infrastructure for rapid delivery of resource-intensive applications brought on by the multimedia revolution," Kramer says. "Stratm extends the capabilities of existing switches while providing the foundation for emerging services such as IP switching."
Stratm technology also delivers the industry's first comprehensive WAN ATM implementation of the ATM Forum's recently approved Traffic Management 4.0 specification. For the first time, ATM users have a complete, end-to-end traffic management solution based on industry standards, enabling them to manage network congestion in a standard fashion from the desktop to the public WAN. Better traffic management will allow Stratm customers to ease network congestion, scaling networks to support millions of user connections and thousands of calls per second through a single switch.
"The pilot phase of ATM adoption is coming to an end," Kramer concludes. "Customers are demanding high-density, high-performance, intelligent ATM platforms and switch products. Cisco is meeting that demand with its Stratm technology."
| Stratm Innovations |
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| Improved applications throughput--Advanced buffering technology, hardware-based virtual circuit queuing, and high-density, high-speed ATM connectivity ensures optimum throughput.
Increased efficiency and performance--Stratm technology increases network efficiency and boosts performance through the distribution of critical ATM functions, such as traffic management and call processing, to every Stratm card. Greater scalability--Stratm dramatically increases the number of simultaneous connections supported, calls processed, and physical ports available per interface card. Investment protection--Inherent scalability and support for key ATM standards ensures Stratm's compatibility with existing equipment and emerging capabilities such as IP switching. |
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Cisco Systems scores another industry first with the introduction of its Inverse Multiplexing for ATM Trunk Module (IMATM) products, which are designed to lower the cost, accelerate the deployment, and simplify the operation of broadband networks.
A strategic part of Cisco's ATM switching and routing product lines, IMATM products enable Internet service providers, carriers, and corporations to build redundant and flexible broadband networks, providing Internet access at speeds between T1/E1 (1.544/2.048 Mbps) and DS3/E3 (45/34 Mbps) on a single front card. ATM switches can be connected with as little as a single T1 or E1 connection, and additional bandwidth added in T1/E1 increments to form single or multiple logical links as requirements increase.
"The delivery of ATM inverse multiplexing is an important milestone in speeding ATM deployment and reducing the cost of building multiservice broadband ATM networks," says Alex Mendez, Vice President of Marketing for Cisco's WAN Switching Business Unit. "ATM inverse multiplexing is ideal for enterprise users and service providers looking to evolve to ATM and wanting to trunk switches at fractional DS3/E3 rates, or for users wanting to bring traffic in from sites that exceed T1/E1 speeds but don't justify a DS3/E3 connection."
LDDS WorldCom (Tulsa, Oklahoma), one of Cisco's first IMATM customers, is relying on ATM inverse multiplexing within its StrataCom® BPXTM Service Node ATM switches to simplify network expansion efforts, particularly outside the USA where telecommunications circuit costs are high. "IMATM represents a flexible and affordable trunking option and is available today," says Russ Ray, Vice President of Engineering at LDDS WorldCom. "It delivers fractional DS3/E3 rates at a compelling price point while allowing us to maintain all the inherent benefits of ATM."
Based on an interim ATM inverse multiplexing specification developed by Cisco, the new IMATM products are available immediately for the StrataCom BPX Service Node ATM switch. Cisco also plans to make IMATM a strategic part of its ATM switching and routing product lines, which include Cisco LightStream® 1010 campus ATM switches and the Cisco 7000 router family. Customers' ATM investments will be protected with free software upgrades when the final IMA standard is released from the ATM Forum.
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Cisco is delivering new software and hardware advances for building fault tolerance and redundancy into LAN emulation (LANE)-based ATM networks, speeding the deployment of ATM in production environments without requiring changes to existing, standard ATM LANE clients. These standards-based solutions include:
Users are praising these advancements for the increased reliability they imply. "End users connected to our ATM network must always be able to reach their default routers to other VLANs and to the Internet," says Allen Robel, Senior Network Planner at Indiana University. "HSRP for LAN Emulation provides quick cutover to a backup router, allowing us to deploy a highly survivable infrastructure that is transparent to the user." Cisco's SSRP and ATM LANE module with dual physical-layer interfaces for the Catalyst 5000 Switch will further strengthen the redundancy of this environment, he adds.
Cisco developed the new specifications in conjunction with its ATM interoperability partners and other vendors to ensure compatibility with a wide range of ATM networking equipment.
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After an extensive beta-testing period, Cisco Systems has announced the availability of the AtmDirectorTM graphical, system-level management application that simplifies the installation and administration of ATM in switched internetworks.
"Innovative customers are turning to ATM as a universal networking architecture that enables all kinds of traffic--voice, data, and video--to flow over mid-speed to high-speed data highways," notes Cecil Christie, an ATM product manager in Cisco's Workgroup Business Unit. "Despite ATM's rosy promise, a few stumbling blocks remain. Chief among these is the need for robust ATM management tools."
Because ATM is connection-oriented--unlike Fiber Distributed Data Interface (FDDI), Token Ring, and Ethernet--administrators need to be able to set up virtual connections, monitor various types of link statistics, and trace complex point-to-multipoint connections when tracking down information about an ATM network and its users. "Switched ATM internetworking adds new dimensions to the management process," Christie stresses. "The old tools and applications, designed for analyzing and managing multiple users residing on shared LANs, do not provide the functionality necessary for switched networks."
The AtmDirector software is ideal for configuring, monitoring, and troubleshooting a network of Cisco LightStream® ATM switches and ATM-attached Cisco routers and CatalystTM LAN switches. It automatically discovers and illustrates the topology of ATM networks, displays real-time link information. Network managers can troubleshoot the network by using AtmDirector to select any virtual connection on an ATM link and trace its entire path. Additionally, the application provides an intuitive interface for creating permanent virtual circuits (PVCs) across the ATM network, where ATM signaling and routing protocols are used to ease configuration during connection setup.
"Simply clicking on a link in the AtmDirector topology map reveals that link's parameters along with a tabular list of all active, virtual connections," Christie explains. "These can be sorted by link utilization or connection identifier values to facilitate troubleshooting."
AtmDirector software is fully integrated with the CiscoViewTM graphical device management application that provides dynamic status, statistics, and comprehensive configuration information.
| AtmDirector Software Rises to the Challenge |
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Among other capabilities, the AtmDirector software:
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