ForeRunner
ATM Switch Network Configuration Manual
2 - 1
Confi
guring
Clas
sic
a
l
IP
CHAPTER 2
Configuring Classical IP
2.1 Introduction
This chapter describes how to design, configure, and maintain a Classical IP ATM network.
The term classical indicates that the ATM network has the same properties as existing legacy
LANs. That is, even though ATM technology allows for large, globally connected networks,
for example, it is only used in the LAN environment as a direct replacement of existing LAN
technology. The classical model of LANs connected through IP routers is maintained in ATM
networks. RFC-1577 provides the standard for Classical IP over ATM.
Classical IP over ATM is different than IP in legacy LANs in that ATM provides a virtual con-
nection environment through the use of Permanent Virtual Circuits (PVCs) and/or Switched
Virtual Circuits (SVCs). SVC management is performed via the ATM Forum UNI 3.0 Specifica-
tion, which specifies Q.2931. Q.2931 is a broadband signalling protocol designed to establish
connections dynamically at the User-Network Interface (UNI). Q.2931 uses Service Specific
Connection Oriented Protocol (SSCOP) as a reliable transport protocol, and all signalling
occurs over VPI: 0, VCI: 5. Q.2931 connections are bidirectional, with the same VPI/VCI pair
used to transmit and receive.
Once a Classical IP connection has been established, IP datagrams are encapsulated using
IEEE 802.2 LLC/SNAP and are segmented into ATM cells using ATM Adaptation Layer type 5
(AAL5). Additionally, the default Maximum Transmission Unit (MTU) is 9,180 bytes (the
SNAP header adds 8 more bytes) with a maximum packet size of 65,535 bytes. There is cur-
rently no support for IP broadcast datagrams or IP multicast datagrams in a Classical IP envi-
ronment.
Summary of Contents for forerunner series
Page 6: ......
Page 16: ...TOC 10 ForeRunner ATM Switch Network Configuration Manual Table of Contents ...
Page 20: ...LOF 4 ForeRunner ATM Switch Network Configuration Manual List of Figures ...
Page 22: ...LOT 2 ForeRunner ATM Switch Network Configuration Manual List of Tables ...
Page 30: ...viii ForeRunner ATM Switch Network Configuration Manual Preface ...
Page 144: ...3 58 ForeRunner ATM Switch Network Configuration Manual Configuring an Emulated LAN ...
Page 180: ...6 12 ForeRunner ATM Switch Network Configuration Manual ATM Forum PNNI ...
Page 220: ...9 6 ForeRunner ATM Switch Network Configuration Manual Configuring Timing ...
Page 300: ...D 24 ForeRunner ATM Switch Network Configuration Manual Configuring FramePlus Modules ...
Page 308: ...Acronyms 8 ForeRunner ATM Switch Network Configuration Manual Acronyms ...
Page 346: ...Glossary 38 ForeRunner ATM Switch Network Configuration Manual Glossary ...
Page 352: ...Index 6 ForeRunner ATM Switch Network Configuration Manual Index ...