Cisco 7200 VXR router User Manual page 60

Functional Overview
The following example shows the display for the first port on the Fast Ethernet port adapter
in port adapter slot 3:
Router# sh int fastethernet 3/0
FastEthernet3/0 is up, line protocol is up
Hardware is DEC21140, address is 0000.0000.0000 (bia 0000.0000.0000)
Internet address is 1.1.1.8
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, rely 255/255, load 1/255
Encapsulation ARPA, loopback not set, keepalive not set
Full-duplex, 100Mb/s, 100BaseTX/FX
ARP type: ARPA, ARP Timeout 04:00:00
For complete descriptions and instructions of the commands used to configure your
Cisco 7200 VXR router, refer to the Configuration Fundamentals Configuration Guide and
Configuration Fundamentals Command Reference publications, which are available on the
Documentation CD-ROM or in print.
MAC-Layer Address
All LAN interfaces (ports) require unique MAC-layer addresses, also known as hardware
addresses. Typically, the MAC address of an interface is stored on a memory component
that resides directly on the interface circuitry; however, the OIR feature requires a different
method. (For a description of OIR, see the "Online Insertion and Removal" section on page
51.)
The OIR feature allows you to remove a port adapter and replace it with another identically
configured one. If the new port adapter matches the port adapter you removed, the system
immediately brings it on line. In order to allow OIR, an address allocator with unique MAC
addresses is stored in an EEPROM on the router midplane. Each address is reserved for a
specific port and slot in the router regardless of whether a port adapter resides in that slot.
The MAC addresses are assigned to the slots in sequence. The first address is assigned to
slot 0, and the last address is assigned to slot 4 in the Cisco 7204VXR or to slot 6 in the
Cisco 7206VXR. This address scheme allows you to remove port adapters and insert them
into other routers without causing the MAC addresses to move around the network or be
assigned to multiple devices.
1-50 Cisco 7200 VXR Installation and Configuration Guide
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