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Cisco 7401ASR Installation and Configuration Guide
OL-5419-01 B0
Chapter3 Starting and Configuring
Functional Overview
The Media Access Control (MAC) or hardware address is a standardized da ta link l ayer a ddr es s tha t is
required for certain network interface types. These addresses are not used by other devices in the
network; they are specific and unique to each port. The Cisco 7401ASR router uses a specific method to
assign and control the MAC addresses of its port adapters. For a descript ion of the MAC address, see the
“MAC Address” section on page3-3.
You can identify port adapter slots by using software commands. To display information about all port
adapter slots, use the show interfaces command. To display information about a specific port adapter
slot, use the show interfaces command with the port adapter type and slot number in the format
showinterfaces port-adapter-type slot-numbe r/port -number. If you abbreviate the command (sh int)
and do not specify port adapter type and slot number (or argume nts), the system interprets the command
as show interfaces and displays the status of all port adapters and ports.
The following example shows how the show interfaces command, used without arguments, displays
status information (including the physical port adapter number) for each po rt adapt er in a Cisco
7401ASR router.
In the following example, most of the status information for each interface is omitted.
Router# show interfaces
GigabitEthernet0/0 is up, line protocol is down
Hardware is i82543 (Livengood), address is 0000.0000.0000 (bia 0000.0000.0000)
Internet address is 1.1.1.2
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
(display text omitted)
GigabitEthernet0/1 is administratively down, line protocol is down
Hardware is i82543 (Livengood), address is 0000.0000.0000 (bia 0000.0000.0000)
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
(display text omitted)
Serial1/0:0 is down, line protocol is down
Hardware is Multichannel T1
MTU 1500 bytes, BW 1536 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
(display text omitted)
alarm present
Timeslot(s) Used:1-24, subrate:64Kb/s, transmit delay is 0 flags
You can also use arguments such as the interface type (Ethernet, Token Ring, ATM, and so forth) and
the port address (slot-number/port-number) to display information about a specific interface only.
The following example shows the display for the first port on the Gigabit Ethernet port adapter in the
port adapter slot (1):
Router# show interface g1/0
GigabitEthernet1/0 is up, line protocol is down
Hardware is i82543 (Livengood), address is 0000.0000.0000 (bia 0000.0000.0000)
Internet address is 1.1.1.2
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex mode, link type is autonegotiation, media type is SX
output flow-control is off, input flow-control is off
ARP type:ARPA, ARP Timeout 04:00:00