Mac Address Allocator - Cisco 7000 Hardware Installation And Maintenance

Functional Overview
You can identify interface ports by physically checking the slot/port location on the back of the
router or by using software commands to display information about a specific interface or all
interfaces in the router. To display information about every interface, use the show interfaces
command (interfaces is plural) without variables. To display information about a specific interface,
use the show interface command (interface is singular) with the interface type and port address in
the format show interface [type slot/port]. If you abbreviate the command (sho int) and do not
include variables, the system interprets the command as show interfaces and displays the status of
all interfaces.
Following is an example of how the show interfaces command, which you use without variables,
displays status information (including the physical slot and port address) for each interface in the
router.
In this example, most of the status information for each interface is omitted.
You can also use variables such as the interface type (Ethernet, Token Ring, FDDI, serial, or HSSI)
and the port address (n/n) to display information about a specific interface only. The following
example shows the display for the top Ethernet port on an EIP in slot 4:
For complete command descriptions and instructions, refer to the related software documentation on
UniverCD or in the printed manuals.

MAC Address Allocator

All network interface connections (ports) require a unique Media Access Control (MAC)-layer
address, which is also known as a physical or hardware address. Typically, the MAC address of an
interface is stored on a component that resides directly on the interface circuitry, as it does on our
earlier router platforms (for example, on individual appliques). Every interface on the earlier
platforms contains a programmable read-only memory (PROM) component with a unique MAC
address for that interface. The router system code reads the PROM for each interface in the system,
learns the MAC addresses, and can then initialize appropriate hardware and data structures.
1-56 Cisco 7000 Hardware Installation and Maintenance
7000# show int
Fddi3/0 is up, line protocol is up
Hardware is cxBus Fddi, address is 0000.0c02.adf1 (bia 0000.0c02.adf1)
(display text omitted)
Ethernet4/0 is administratively down, line protocol is down
Hardware is cxBus Ethernet, address is 0000.0c02.d0cc (bia 0000.0c02.d0cc)
(display text omitted)
Ethernet4/1 is administratively down, line protocol is down
Hardware is cxBus Ethernet, address is 0000.0c02.d0cd (bia 0000.0c02.d0cd)
(display text omitted)
TokenRing2/0 is administratively down, line protocol is down
Hardware is cxBus Token Ring, address is 0000.3040.8b4a (bia 0000.3040.8b4a)
(display text omitted)
7000# show int ether 4/0
Ethernet4/0 is up, line protocol is up
Hardware is cxBus Ethernet, address is 0000.0c02.d0ce (bia 0000.0c02.d0ce)
Internet address is 131.108.7.1, subnet mask is 255.255.255.0
MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, rely 255/255, load 1/255
Encapsulation ARPA, loopback not set, keepalive set (10 sec)
(display text omitted)