RAD Data comm IPmux-1 - Manual (Page 26)

Chapter 1 Introduction IPmux-1/1E Installation and Operation Manual
1-18 Functional Description
Table 1-2. Ethernet Frame Structure
Field length (bytes) Field
7 Preamble
1 SFD
6 Destination MAC Address
6 Source MAC Address
2 Type
1 Vers/HLEN
1 Service Type
2 Total Length
2 Identification
1 Flags/Fragment Offset (most)
1 Fragment Offset (least)
1 Time to Live
1 Protocol
2 Header Checksum
4 Source IP Address
4 Destination IP Address
2 UDP Source Port
2 UDP Destination Port
2 UDP Message Length
2 UDP Checksum
... Payload
4 CRC
VLAN Support
VLAN, according to IEEE 802.1p&q, adds four bytes to the MAC layer of the
Ethernet frame. The contents of these bytes, MAC layer priority and VLAN ID, can
be set by the user. In this mode, only VLAN format frames are sent and received
by IPmux-1. Figure 1-17 describes the VLAN tag format.
MAC
Layer
IP Layer
MAC
Layer
UDP
Layer
Data
Layer
LLC
Layer
Note: IEEE 802.1p&q VLAN
Tagging (additional 4 bytes if
enabled)
Note: The UDP source port
field is used to transfer the
destination bundle number.
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