Mac Addresses - Cisco Catalyst 6500 Series Installation Manual

Chapter 1 Product Overview
Port Addresses
Interface ports maintain the same addresses regardless of whether other modules
are installed or removed. However, when you move a module to a different slot,
the first number in the address changes to reflect the new slot number. For
example, on a 48-port 10/100BASE-T switching module in slot 2, the address of
the left port is 2/1 and the address of the right port is 2/48. If you remove the
48-port 10/100BASE-T switching module from slot 2 and install it in slot 4, the
addresses of those same ports become 4/1 through 4/48.
The supervisor engine is n/1 to n/2 because it supports two interfaces: ports 1
and 2. Switching modules are addressed n/1 through n/N.
You can identify each module port by checking its slot and port location on the
switch. You can also use software commands to display information about a
specific interface, or all interfaces, in the switch. To display information about
every interface, enter the show port command without parameters. To display
information about a specific interface, enter the show port command with the
module (slot) number and port number in the format show port
[mod_num/port_num].

MAC Addresses

All network interface connections (ports) require a unique MAC address. The
MAC address of an interface is stored in electrically erasable programmable
read-only memory (EEPROM) on a component that resides directly on the
interface circuitry. The switch system code reads the EEPROM for each interface
in the system, learns the MAC addresses, and then initializes appropriate
hardware and data structures. Each VLAN in the spanning tree has one unique
MAC address. This addressing scheme gives the switch the intelligence to identify
the state (connected or not connected) of each interface. When you hot swap a
module, the MAC address changes with the module.
Catalyst 6500 Series Switch Module Installation Guide
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