SAN JOSE, Calif., March 1, 1995 -- A blueprint that network managerscan follow to start implementing multimedia applications today -- withoutexpensive and disruptive upgrades -- has been announced by Cisco Systems.
Cisco is the first vendor to provide all three of the key technologiesthat will let businesses deploy a comprehensive solution for real-time,collaborative applications combining text, voice, images and video:end-to-end quality of service, multipoint packet delivery, and scalablebandwidth.
John Chambers, Cisco president and CEO, said, "It is widely believedthat gaining the benefits of multimedia means making a massive investmentto deploy emerging high-speed technologies. But multimedia applicationscan be delivered today, without a huge new resource commitment. Businessescan realize immediate value from such widely-used applications asmultimedia e-mail, desktop videoconferencing, distance learning andcollaborative computing. And ATM, high-speed switching and other advancedtechnologies can be brought into the blueprint when appropriate."
Cisco is addressing users' immediate need for multimedia applicationsupport, Chambers said, with enhancements to its Internetwork OperatingSystem (IOS) software and with a number of multimedia-orientedfeaturesalready available in its products. Key new features being announced todayinclude a weighted traffic queuing algorithm and packet multicastingprotocols to support the flexible bandwidth usage and improved networkquality of service that are critical to running multimedia applications.
The Four-Tier Multimedia Industry
Chambers defined a four-tier multimedia industry as including providersof multimedia content (e.g., news and entertainment), applicationdevelopers (e.g., software for distance learning, videoconferencing,imaging), platform builders (e.g., Silicon Graphics, Sun, Intel, Apple) andnetwork vendors."Multimedia applications are already moving into mainstreambusinesses," he said. "The challenge will be to build a network 'pipe'both big enough to accommodate multiple traffic types and flexible enoughto differentiate their varying needs. This can be done only through closecooperation between the participants in all four tiers of the multimediaindustry."
The Three Key Elements of Multimedia:
- Guaranteed End-to-End Quality of Service
By mid-1995 the Cisco IOS will incorporate a weighted fair queuingalgorithm to reduce latency and minimize jitter, two factors that candegrade network quality of service in desktop conferencing. In voicecommunication, for example, variable latency for different packets producesannoying pops and clicks. Weighted fair queuing enables the network toidentify various types of network traffic and assign them consistentrouting priorities weighted to minimize latency caused by network delays.
Cisco's IOS already includes priority queuing, which allows the user toplace high-priority traffic at the head of the queue; and custom queuing,which guarantees minimum bandwidth to selected traffic. Weighted fairqueuing further improves these features by automating configuration therebyeliminating manual configuration to distinguish data types.
In addition, Cisco is working with the Internet Engineering Task Force(IETF) and leading multimedia application developers to bring the ResourceReservation Protocol (RSVP) to market. RSVP is an end-to-end internetworkprotocol that allows the applications to dynamically reserve necessaryresources for different classes of service using the capabilities of theunderlying network (e.g., FDDI, ATM, Frame Relay). RSVP is designed tosupport multiple network layer protocols, including TCP/IP,Novell IPXand AppleTalk. Cisco expects to deliver RSVP in the second half of 1995.
- Multicast Packet Delivery For Efficient Bandwidth Usage
Cisco is the first major networking vendor to support IP Multicastmultiprotocol packet delivery on both router and switch platforms. With IPMulticast, the sending computer transmits a packet addressed to allintended recipients, and the network replicates the packet only whennecessary. This approach is far more efficient than two traditionaltechniques which waste considerable bandwidth: unicast (which duplicatesthe data transmission for each recipient) and broadcast (which forwardspackets to the entire network to ensure they reach intended recipients).
Cisco began shipping IP Multicast with the IOS in late 1994, andworkstation vendors Sun Microsystems and Silicon Graphics are alreadyshipping the protocol with their products. Microsoft will support IPMulticast in the Windows 95 operating system.
IP Multicast also is being used to build the MBONE experimentalbackbone running on the public Internet; the IETF uses MBONE to disseminateproceedings of general sessions and technical forums, and for research oncollaborative computing. Cisco worked with the IETF to define a scalablemulticast routing protocol, Protocol Independent Multicast (PIM). Cisco isshipping full support for PIM today to allow networked devices to buildefficient trees for multicast packets. PIM is currently on the standardstrack and will be updated to meet any additional requirements of the IETF.
To enhance multicast packet delivery in Apple Macintosh environments,Cisco last month licensed from Apple Computer the Simple Multicast RoutingProtocol (SMRP), which allows users to broadcast digital audio and videoover the network from their desktops. SMRP, designed to minimize theamount of network bandwidth required to distribute multimedia data ondistributed networks, works in conjunction with multicast extensions to theAppleTalk protocol, in use on millions of Macintosh systems. SMRP will beavailable on Cisco products in the third quarter of 1995.
- Scalable Bandwidth to Support Variable Multimedia Requirements
Cisco's current product line includes a broad range of solutions toprovide users with the variable amounts of network bandwidth required bymultimedia applications.
In workgroupenvironments, many individual desktops often share asingle LAN segment. The most cost-effective way to give these users morebandwidth is by microsegmenting the LAN with fewer users on each segment.Such microsegmentation can be implemented gradually, as application usagepatterns evolve, using Cisco's workgroup switches families, Catalyst andthe Kalpana Etherswitch.
At the campus or backbone level,Cisco supports both FDDI and ATMrouting and switching for increasing backbone bandwidth. Cisco 4500 and7000family routers feature FDDI interfaces; and Cisco offers two ATMswitches, theModel A100HyperSwitch for workgroup connectivityand the LightStream 2020for enterprise-wide ATM connectivity.
For the wide-area network, Cisco offers a comprehensive set oftechnologies, including dedicated lines, Frame Relay, SMDS, ISDN and ATM.Cisco's bandwidth-on-demand techniques, which enable a router to assignadditional bandwidth when traffic requires it, are especially well suitedto multimedia networking.
Posted: Feb 28 19:32:45 1995
