Cabletron Systems DMS-100 manual Appendix I Obtaining a MAC address, MAC address format, 185

Models: DMS-100

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Appendix I: Obtaining a MAC address

This appendix provides information on media access control (MAC) addresses1, and on obtaining a MAC address for the Ethernet interface unit (EIU).

Overview

The standard among manufacturers of Internetworking hardware is that the MAC address is hard-coded in read-only memory (ROM) on each device. The address becomes a unique identifier, and this standard ensures that no two devices have the same identifier.

The EIU departs from this standard in that, while Nortel controls the MAC address and the address is still unique, the operating company is responsible for recording this address in datafill. While there is flexibility in assigning the MAC address to EIU, this flexibility can cause problems if MAC addresses are not unique across the network or the Internetwork. The operating company must ensure that the datafilled address is correct, or addressing conflicts can occur.

Administrative personnel assign a unique MAC address to each EIU using table control datafill in table LIUINV.

MAC address format

As defined by IEEE Standard 802.3, a MAC address is either 16 or 48 bits long. SuperNode supports 48-bit addresses. The 48-bit MAC address structure is shown in figure 47.

1.The MAC address is also known as an Ethernet address. In this document, the industry - standard term MAC address is used.

DMS-100 Family EIU User Guide TELECOM12

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Cabletron Systems DMS-100 manual Appendix I Obtaining a MAC address, MAC address format, 185