Black Box LR1530A-EU-R3 Manuel d'utilisateur télécharger pdf (Page 73)

APPENDIX B

OCTET LOCATIONS ON

ETHERNET FRAMES

This appendix provides octet locations for the various portions of

three of the common Ethernet frames. When creating pattern filters

these diagrams will assist in the correct definition of the patterns. The

offset numbers are indicated by the numbers above the frame

representations.

Note the differences in the TCP/IP and Novell frames when bridging

and when routing. When routing, the TCP/IP and Novell frames are

examined after the Level 2 Ethernet portion of the frame has been

stripped from the whole data frame. This means that the offset

numbers now start from 0 at the beginning of the routed frame and

not the bridged frame.

Some of the common Ethernet type codes are also shown here. The

Ethernet type codes are located at offset 12 of the bridged Ethernet

frame.

1 2 ... 68 69 70 71 72 73 74 75 76 77 78 ... 101 102

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Black Box LR1530A-EU-R3 Manuel d'utilisateur Page 73