ATM-to-the-desktop: its position and advantages in emerging networks

Abstract

Given t h a t A T M is e x p e c t e d t o b et h e d o m i n a n t b a c k b o n e technology ( w i t h backbone speeds s t a r t i n g at 155 M b p s ) , t w o o p t i o n s exist for a n e t w o r k a d m i n i s t r a t o r w h e n replacing a n existi n g section of his n e t w o r k a n d for a d d i n g a n e w section: (1) install a switched (possibly high-speed) LAN, or (2) install a n all A T M solution (ATM-tothe-Desktop), e i t h e r n a t i v e or w i t h L A N E m u l a t i o n . We will present a c o m p a r i s o n of t h e s e t w o options, w i t h e m p h a s i s o n evaluating t h e i r respective performances. We will illustrate t h e s e discussions w i t h m e a s u r e d data a n d m a t h e m a t i c a l models. r. INTRODUCTIOXThe predominant LAN technology today is 10 Mbps Ethernet (10BASE-T). However, with the rapid increase in PC capability, the explosion of World Wide Web activity, the development of throughput intensive applications, etc., network administrators are experiencing increasingly unacceptable congestion. In response to this, industry is rushing to provide Ethernet switches with a variety of capabilities (100BASE-T and OC3 ATM uplinks, half-and full-duplex, Priority Access Control Enabled or PACE, and other mechanisms) that take advantage of the benefits of switching technology, providing congestion relief and collision reduction (with the definition of smaller collision domains). while still utilizing the CSMA/CD physical access methods. Some of this network revolution (especially in the area of application development) has been the result of the anticipation and introduction of ATM technology, that offers an enormous range of throughputs (from 25 Mbps to Gigabits per sec), as well as a vast array of network management capabilities (Quality of Service guarantees, flow/congestion control: connection control, etc.). For these reason;, most experts and network administrators agree that ATM will be the future network backbone technology.Clearly, today's network administrators should take advantage of emerging Ethernet switching technology to relieve congestion on their existing Ethernet installations. However, a very important question facing network administrators is what to install when upgrading or expanding their network: higher-speed switched Ethernet, or ATM-to-the-Desktop (all ATM, with 25 Mbps ATM technology locally).A transitional solution between a traditional LAN (such as Ethernet) and a pure ATM network is provided by ,4TM LAN Emulation (LANE). LANE (either Ethernet or Token Ring) over ATM allows migration of present LAN applicaDepartment of Computer Science Box 8206 North Carolina State University Raleigh, NC 27695 tions to an L4TM network, with some of the benefits such a network brings: scalability of speed with multiple uplinks, network access control per connection a t call set-up, multiple routes with route selection per connection, virtual LAN assignment, etc. (The advantages of ATM from a function perspective are well documented and are only summarized her...