Framing type
IPX/SPX allows you to set the
type of ``framing'' performed by the network adapter driver.
You may want to change this parameter if you
reconfigure a network segment to use a
different framing type.
The framing types supported by IPX/SPX are described in:
The Ethernet 802.3 with 802.2 headers framing type conforms to the IEEE 802.3 and IEEE 802.2 standards. This framing type is the default Ethernet framing type in most Novell® NetWare networks.
The main feature of this framing type is the SAP (Service Advertising Protocol) fields, which indicate the protocol type. For Novell networks, these fields are set to 0xe0, which indicates that the upper layer protocol is IPX. Ethernet 802.3 with 802.2 header frames have this format:
Table A-5 802.3 with 802.2 headers
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Header Field Size
---------------------------------------
802.3 destination address 6 octets
802.3 source address 6 octets
802.3 length 2 octets
802.2 destination SAP 1 octet
802.2 source SAP 1 octet
802.2 control 1 octet
data ...
---------------------------------------
The Ethernet 802.3 framing type is commonly used in Novell networks, particularly with native NetWare 2.x and 3.x servers. This framing type was developed by Novell before the IEEE 802.2 standard was complete and is sometimes referred to as ``802.3 raw''.
The main feature of the Ethernet 802.3 framing type is the use of the hardcoded 0xffff value in the frame header. Ethernet 802.3 frames have this format:
Table A-6 802.3
----------------------------------------------------
Header Field Size
----------------------------------------------------
802.3 destination address 6 octets
802.3 source address 6 octets
802.3 length 2 octets
802.3 0xffff 2 octets
data ...
----------------------------------------------------
The Ethernet II framing type is sometimes referred to as the ``XEROX PARC version of Ethernet''.
The main feature of this framing type is its simple frame structure. Ethernet II frames have this format:
Table A-7 Ethernet II
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Header Field Size
---------------------------------------
Ethernet II address 6 octets
Ethernet II source address 6 octets
Ethernet II type 2 octets
data ...
---------------------------------------
Ethernet SNAP framing allows network protocol stacks to use Ethernet II frames on IEEE style networks without modification. SNAP framing is most commonly used for Token-Ring networks.
The main feature of this framing type is the use of three protocol headers: IEEE 802.3, IEEE 802.2, and SNAP. Ethernet SNAP frames have this format:
Table A-8 Ethernet SNAP
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Header Field Size
---------------------------------------
802.3 destination address 6 octets
802.3 source address 6 octets
802.3 length 2 octets
802.2 0xaa 1 octet
802.2 0xaa 1 octet
802.2 UI 1 octet
SNAP protocol ID 1 octet
SNAP type 1 octet
data ...
---------------------------------------
The Token-Ring framing type conforms to the IEEE 802.5 and IEEE 802.2 standards.
The main feature of this framing type is the SAP (Service Advertising Protocol) fields, which indicate the protocol type. For Novell networks, these fields are set to 0xe0, which indicates that the upper layer protocol is IPX. Token-Ring frames have this format:
Table A-9 Token-Ring
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Header Field Size
------------------------------------------
802.5 AC 1 octet
802.5 FC 1 octet
802.5 destination address 6 octets
802.5 source address 6 octets
802.5 routing information 0-18 octets
802.2 destination SAP 1 octet
802.2 source SAP 1 octet
802.2 control 1 octet
data ...
------------------------------------------
Token-Ring SNAP allows network protocol stacks to use Ethernet II frames.
The main feature of this framing type is the use of three protocol headers: IEEE 802.5, IEEE 802.2, and SNAP. Token-Ring SNAP frames have this format:
Table A-10 Token-Ring SNAP
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Header Field Size
------------------------------------------
802.5 AC 1 octet
802.5 FC 1 octet
802.5 destination address 6 octets
802.5 source address 6 octets
802.5 routing information 0-18 octets
802.2 0xaa 1 octet
802.2 0xaa 1 octet
802.2 UI 1 octet
SNAP protocol ID 1 octet
SNAP type 1 octet
data ...
------------------------------------------