This article is a series of questions and answers on the component technologies in Apple Open Transport.

• Q: What technologies and components are included in Open Transport?
• A: Open Transport consists of new programming interfaces, new implementations of protocol stacks, a new model for integration of networking with the underlying operating system, and new human interface components. Open Transport supports LANs and WANs, and integrates serial communications and modems as well as remote (dial-up) networking in a consistent model for end-users, network managers, and developers.
• Q: What current Mac OS technologies, components, and products will Open Transport replace?
• A: Open Transport replaces the current implementations of AppleTalk and MacTCP, including the protocols and the existing Network, MacTCP, and AdminTCP control panels. Open Transport products replace the existing "AppleTalk Connection for Macintosh" and "TCP/IP Connection for Macintosh" software.

  Open Transport is also designed to replace the Connection Manager and the Communications Resource Manger of the current Communications ToolBox architecture.

• Q: Does this mean that Apple is migrating serial communications away from the Communications ToolBox (CTB)?
• A: Not entirely. The CTB File Transfer and Terminal Managers continue to be supported. They will be taken forward into a future OS release, although on new Open Transport/Serial underpinnings. Over time, the CTB Connection Manager and its tools will be phased out in favor of Open Transport. The transition will include a period of backward compatibility to assure a smooth migration for developers and customers.
• Q: Which protocols will be available for Open Transport?
• A: Open Transport version 1.0 includes support for AppleTalk, TCP/IP, and serial communications. Over time, subsequent releases will add support for Point to Point Protocol (PPP), NetWare (NCP/IPX), and X.25. Other protocols are under investigation, or may be available from third parties.
• Q: Are there any changes in AppleTalk or TCP/IP with Open Transport?
• A: Yes. The new Open Transport/AppleTalk and Open Transport/TCP protocol implementations both have been implemented as Open Transport STREAMsmodules and as native code on Power Macintosh computers. They support the new XTI APIs and can be dynamically loaded and unloaded as needed.

  Both protocols also support dynamic reconfiguration (changed settings without requiring reboot), and feature new configuration applications offering Basic, Advanced, and Administrator tools.

  Each protocol stack also offers addition protocol-specific feature enhancements.

• Q: What are some of the upgraded features of Open Transport/TCP?
• A: With the overwhelming acceptance of TCP/IP protocols in the marketplace, and the tremendous excitement and visibility of the Internet -- Apple has made a significant investment in bringing a workstation-class implementation of TCP/IP protocols to the Mac OS. As before with MacTCP, Open Transport/TCP is a full 32- bit stack. But with Open Transport/TCP, we add support for:
  • Dynamic Host Configuration Protocol (DHCP), for centralized IP address management.
  • IP multicast, for participation as an MBone client.
  • Dynamic path MTU discovery, for more efficient network use in heterogeneous network topologies.
  • Simultaneous TCP connections limited only by installed memory and processor power, for increased functionality as a Internet or other TCP/IP network server.
  • Ethernet version 2 and IEEE 802.3 framing, for better interoperability with a wider range of TCP/IP hosts.
  • Implicit and explicit domain name search paths, for increased control of domain name resolution.
  • Multiple IP routers with fail-over, for increased robustness in mission critical applications.

  And the architecture that supports Open Transport/TCP is itself based on a direct port of the Unix System V r4 STREAMs environment - a proven, robust and scalable OS networking technology.

• Q: What are some of the upgraded features of Open Transport/AppleTalk?
• A: Open Transport/AppleTalk includes new support for statically assigned (manually administered) protocol addresses (statically assigned AppleTalk is not supported in Open Transport 1.0). This allows AppleTalk nodes to be managed using protocol address as a unique and stable identifier. It also reduces some of the network traffic associated with AppleTalk's dynamic address assignment features. Dynamic addressing continues to be available for those customers who prefer the automated address allocation.
• Q: Is this "AppleTalk Phase 3"?
• A: No. Open Transport/AppleTalk is a new, modern implementation of the AppleTalk Phase 2 protocol architecture for the Mac OS - from the people who invented AppleTalk.
• Q: What about NCP/IPX? Will Novell deliver an Open Transport-based Macintosh client that uses native IPX protocols as the transport layer?
• A: Apple and Novell are jointly and publicly committed to making Macintosh a first-class NetWare client. An Open Transport-ready implementation of NetWare protocols and client services is under investigation. At this time, the companies are not ready to announce product or availability details.
• Q: When will additional protocol stacks be available?
• A: Open Transport will gain support for Point to Point Protocol (PPP), supporting both AppleTalk and TCP/IP communications, with the release of the next generation of Apple Remote Access products scheduled for later in 1995. Other protocol support, including AppleTalk Secure Datastream Protocol (ASDSP), X25, DECnet, SNA, SNMP, and ATM LAN-E, is underway at Apple and with third party developers.
• Q: Which datalinks will be supported by Open Transport?
• A: Open Transport version 1.0 includes support for LocalTalk and Ethernet LANs, and serial communications ports. Modem and ISDN support will come with the introduction of PPP. Subsequent releases will add support for Token Ring, fast Ethernet, FDDI, and ATM LANs. Other datalinks are under investigation, or may be available from third parties.

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