Chapter 5: Tunneling and Application Gateway Chapter 5: Tunneling and Application Gateway Chapter goal: Chapter goal: Multiprotocol environment a Multiprotocol environment Mixing network technologies Mixing network technologies Encapsulation and tunneling Encapsulation and tunneling s Clients and servers in constrained a Clients and servers in constrained environments environments Application gateways Application gateways Application gateway exar Application gateway example Multiprotocol environment Multiprotocol environment Not all machines provide complete TCP/IP Hosts using TCP/P Hosts using TCP/P Not all organizations use TCP/IP exclusively 中?“ to interconnect computers nes, with group using its own ocol suite because Hosts using ATM F Networking has evolved slowly TCP/IP not always avallable y network systems Chief disadvantages Minimize expense Duplication of effort Chapter 5: Tunneling and Application Gateway Mixing network technologies Chapter goal: TCP/IP internet consists of a set of host Multiprotocol environment erconnected by IP gateways(routers) Mixing network technologies r internets use other protocols(e.g CNET, SNA. Encapsulation and tunneling s Clients and servers in constrained environmenTs switching syste Application gateways Many internets have been built that use Application gateway examples witched technologies instead of physical networks For example1 哈工大计算机学院 李全龙 Network Application Development Tunneling and Application Gateway 1 Chapter 5: Tunneling and Application Gateway Chapter goal: „ Multiprotocol environment „ Mixing network technologies „ Encapsulation and tunneling „ Clients and servers in constrained environments „ Application gateways „ Application gateway examples 哈工大计算机学院 李全龙 Network Application Development Tunneling and Application Gateway 2 Chapter 5: Tunneling and Application Gateway Chapter goal: „ Multiprotocol environment „ Mixing network technologies „ Encapsulation and tunneling „ Clients and servers in constrained environments „ Application gateways „ Application gateway examples 哈工大计算机学院 李全龙 Network Application Development Tunneling and Application Gateway 3 Multiprotocol environment „ Not all machines provide complete TCP/IP support „ Not all organizations use TCP/IP exclusively to interconnect computers. „ Most large organizations have several groups of machines, with group using its own protocol suite, because: „ Networking has evolved slowly „ Vendors promoted proprietary network systems „ TCP/IP not always available „ Minimize expense „ User habits 哈工大计算机学院 李全龙 Network Application Development Tunneling and Application Gateway 4 Multiprotocol environment „ Chief disadvantages: „ Duplication of effort „ Limitations of interoperability … Hosts using TCP/IP Ethernet1 … Hosts using TCP/IP Ethernet2 Wide area network that uses ATM Hosts using ATM Hosts using ATM 哈工大计算机学院 李全龙 Network Application Development Tunneling and Application Gateway 5 Chapter 5: Tunneling and Application Gateway Chapter goal: „ Multiprotocol environment „ Mixing network technologies „ Encapsulation and tunneling „ Clients and servers in constrained environments „ Application gateways „ Application gateway examples 哈工大计算机学院 李全龙 Network Application Development Tunneling and Application Gateway 6 Mixing network technologies „ TCP/IP internet consists of a set of host interconnected by IP gateways (routers). „ Other internets use other protocols (e.g. DECNET, SNA…) „ It should be possible to substitute any transport-level switching service in place of a single physical link in another packet switching system. „ Many internets have been built that use switched technologies instead of physical networks. „ For example: