TITLE
    MacTCP: Ethernet And IEEE 802.3 Packets
Article ID:
Created:
Modified: 		4696
12/4/89
12/4/89
TOPIC



    To be useful in our environment, every IP implementation must use an
    "Ethernet-style data link layer (EtherType field)" type packet instead of the
    "IEEE 802.3/2 data link layer (Length field and SAPs)" type packet.

    Which data link layer does MacTCP's IP use?

DISCUSSION

    MacTCP, when using the Ethernet link level protocol as selected via the MacTCP
    CDEV, always uses Ethernet-style packets. We are not aware of any
    implementations of TCP/IP that use the IEEE 802.3 style packets.

    When using the EtherTalk 2.0 link level protocol with MacTCP, IEEE 802.3-style
    packets are used. These packets have AppleTalk encapsulated in them, and they
    must be decapsulated by a DDP/IP gateway, such as a FastPath. These packets
    then are sent to the destination IP address in Ethernet-style packets.

    (NOTE: The DDP/IP gateway needs to be AppleTalk Phase 2-compatible to work as
    described above.)

    The only time IEEE 802.3-style packets are used is when using EtherTalk 2.0.
    These packets are seen only by other EtherTalk 2.0 nodes. EtherTalk 1.x uses
    the Ethernet-style packets.



Document Information
Product Area: Communications-Networking
Category: Protocol and File Format Information
Sub Category: General Topics
Keywords:

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