Mac Address; Online Insertion And Removal - Cisco Router 7204 Installation And Configuration Manual
Cisco systems router installation and configuration guide
Hide thumbs
Also See for Router Cisco 7204:
- Installing (21 pages) ,
- Installation and configuration manual (192 pages) ,
- Regulatory compliance and safety information manual (76 pages)
Table of Contents
Advertisement
Chapter 1
Product Overview
MAC Address
LAN interfaces (ports) require unique MAC 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, refer to the
section
The OIR feature allows you to remove a port or service adapter and replace it with another identically
configured one. If the new port or service adapter matches the adapter you removed, the system
immediately brings it on line. In order to allow OIR, an address allocator with a 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 or service 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 6. This address scheme allows you to remove port and service adapters and insert them into other
routers without causing the MAC addresses to move around the network or be assigned to multiple
devices.
Note that if the MAC addresses were stored on each port or service adapter, OIR would not function
because you could never replace one adapter with an identical one; the MAC addresses would always be
different. Also, each time a port or service adapter was replaced, other devices on the network would
have to update their data structures with the new address, and, if they did not do so quickly enough, could
cause the same MAC address to appear in more than one device at the same time.
Storing the MAC addresses for every slot in one central location means the addresses stay with the
Note
memory device on which they are stored.
Online Insertion and Removal
All port and service adapters in the Cisco 7204 support online insertion and removal (OIR).This function
allows you to install and replace port and service adapters while the router is operating; you do not need
to notify the software or shut down the system power. This provides a method that is seamless to end
users on the network, maintains all routing information, and ensures session preservation.
The following is a functional description of OIR for background information only; for specific
procedures for installing and replacing a port or service adapter in a Cisco 7204 router, refer to the
configuration note that was shipped with the port or service adapter hardware.
The network processing engine and the I/O controller are required system components that cannot be
Caution
removed if the router is operating. Removing the network processing engine or the I/O controller while
the router is operating will cause the router to shut down or crash, and might damage or destroy memory
files.
Each port and service adapter has a bus connector that connects it to the router's midplane. Each
midplane connector has a set of tiered pins in three lengths that send specific signals to the system as
they make contact with the port adapter. The system assesses the signals it receives and the order in
which it receives them to determine if a port or service adapter is being removed or inserted into the
midplane. From these signals, the system determines whether to reinitialize a new interface or shut down
a removed interface. For example, when inserting an port adapter, the longest pins make contact with the
port adapter first, and the shortest pins make contact last. The system recognizes the signals and the
sequence in which it receives them.
OL-5101-02
""Online Insertion and Removal" section on page
1-25".
Cisco 7204 Installation and Configuration Guide
Functional Overview
1-25
Advertisement
Table of Contents
Troubleshooting
