Cisco 7206VXR - VPN Bundle Router, Руководство по установке

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Cisco 7206 Installation and Configuration Guide
OL-5102-02
Chapter 1 Product Overview
Functional Overview
MAC Address
All 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
“
Online Insertion and Removal ” section later in this chapter.
The OIR feature allows you to remove a port adapter or service adapter and replace it with another
identically configured one. If the new port adapter or service adapter matches the adapter you removed,
the system immediately brings it online. In order to enable OIR, an address allocator with a unique MAC
address 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 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 adapters 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 adapter 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 adapter or service adapter was replaced, other devices on the
network would have to update their data structures with the new address. If the other devices did not
update quickly enough, the same MAC address could appear in more than one device at the same time.
Note Storing the MAC addresses for every slot in one central location means the addresses stay with the
memory device on which they are stored.
Online Insertion and Removal
All port adapters and service adapters in the Cisco 7206 support online insertion and removal (OIR).This
function allows you to install and replace port adapters 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 preserves sessions.
The following is a functional description of OIR for background information only; for specific
procedures for installing and replacing a port adapter or service adapter in a Cisco 7206 router, refer to
the configuration note that ships with each port adapter or service adapter.
Caution
The network processing engine and the I/O controller are required system components that cannot be
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 adapter and service adapter has a bus connector that connects it to the router 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 or service adapter. The system assesses the signals it receives and the
order in which it receives them to determine if a port adapter 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 you insert a port or service adapter, the
longest pins make contact with the port or service adapter first, and the shortest pins make contact last.
The system recognizes the signals and the sequence in which it receives them.