ATM Networks

© N. Ganesan, Ph.D.

Chapter Objectives

ATM Interfaces

ATM and other technologies.

ATM

Source: CISCO

ATM Network Building Block

• The main building block of ATM networks is the ATM switch– Workgroup switch– Campus switch– Enterprise switch– Multi-service access switch

ATM Network Hierarchy

Source: CISCO

Work Group Switch

• These switches will have Ethernet and ATM ports

• Used for connecting Ethernet networks to ATM switches

• Note: At the desktop level Ethernet still remains as the leading network technology

Campus Switch

• Used for designing small-scale ATM backbones

• Can be used for connecting various campus backbone technologies – FDDI– Gigabit Ethernet etc.

Move from Traditional to New Backbones

Enterprise ATM Switch

• Used in building large enterprise backbones

• Can be used for integrating different services and technologies on the backbone

Multi-Service Access Switch

• A common ATM infrastructure can be used in a public network to support disparate services– Frame relay– LAN interconnection– Public ATM services

• Their use usually extends beyond a private network to a public network

• Used by service providers to connect MANs and WANs for example

ATM Interface Types

• User-to-Network Interface (UNI)• Network-to-Network Interface (NNI)

Interface Types in a Network

Source: CISCO

ATM Interfaces

• LAN interfaces• Backbone interfaces

ATM to LAN Interface

Source: http://www.cisco.com/univercd/cc/td/doc/cisintwk/idg4/nd2008.htm#28807

LAN Emulation Issues

• Emulate an Ethernet LANs• Map traditional LAN addresses to

ATM addresses

ATM to WAN Interface

Source: CISCODXI – Data Exchange InterfaceHSSI – High Speed Serial InterfaceDSU – Data Service Unit

Load Balancing with ATM Switches

Source: CISCO

Summary

• ATM networks are basically built around ATM switches

• ATM interfaces can be used for integrating disparate WAN technologies

• At the desktop LAN, ATM can be used for emulating the traditional Ethernet environment for example– But, in general, the Ethernet technology is very popular

in terms of ease of use and speed– Therefore, ATM at the LAN front is likely to be used for

connecting Ethernet LANs to the backbone if the backbone is based on ATM

• For the backbone and large public backbones, ATM is bound to become the technology of choice

References

• At CISCO– http://www.cisco.com/univercd/cc/td/

doc/cisintwk/idg4/nd2008.htm

– http://www.cisco.com/univercd/cc/td/doc/cisintwk/idg4/nd2012.htm

• ATM Forum – http://www.atmforum.org/