NAD-chapter5.pdf

文档介绍：Chapter 5: Tunneling and Application Gateway
Chapter goal:
„ Multiprotocol environment
„ work technologies
„ Encapsulation and tunneling
„ Clients and servers in constrained
environments
„ Application gateways
„ Application gateway examples
哈工大计算机学院 work Application Development Tunneling and Application Gateway 1
Chapter 5: Tunneling and Application Gateway
Chapter goal:
„ Multiprotocol environment
„ work technologies
„ Encapsulation and tunneling
„ Clients and servers in constrained
environments
„ Application gateways
„ Application gateway examples
哈工大计算机学院 work Application Development Tunneling and Application Gateway 2
Multiprotocol environment
„ Not all machines plete TCP/IP
support
„ Not anizations use TCP/IP exclusively
to puters.
„ Most anizations have several
groups of machines, with group using its own
protocol suite, because:
„ Networking has evolved slowly
„ Vendors promoted work systems
„ TCP/IP not always available
„ Minimize expense
„ User habits
哈工大计算机学院 work Application Development Tunneling and Application Gateway 3
Multiprotocol environment
Hosts using TCP/IP Hosts using TCP/IP
……
1 2
Wide area
network
Hosts using ATM that uses
ATM
„ Chief disadvantages:
„ Duplication of effort
„ Limitations of interoperability Hosts using ATM
哈工大计算机学院 work Application Development Tunneling and Application Gateway 4
Chapter 5: Tunneling and Application Gateway
Chapter goal:
„ Multiprotocol environment
„ work technologies
„ Encapsulation and tunneling
„ Clients and servers in constrained
environments
„ Application gateways
„ Application gateway examples
哈工大计算机学院 work Application Development Tunneling and Application Gateway 5
work technologies
„ TCP/IP consists of a set of host
interconnected by IP gateways (routers).
„ Other s use other protocols (.
, SNA…)
„ It should be possible to substitute any
transport-level switching service in