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Cisco 7201 Installation and Configuration Guide
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Chapter 3 Starting and Configuring the Router
Functional Overview
Online Insertion and Removal
All port adapters and service adapters in the Cisco 7201 router support online insertion and removal
(OIR). However, it is wise to shut down the interface before removing a port adapter that has active
traffic moving through it. Removing a port adapter while traffic is flowing through the ports can cause
system disruption. Once the port adapter is inserted, the ports can be brought back up.
Caution
As you disengage the port adapter from the router or switch, online insertion and removal (OIR)
administratively shuts down all active interfaces in the port adapter.
OIR 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, although you should not run traffic
through the port adapter you are removing while it is being removed. OIR is 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 7201 router, refer to
the online configuration note for each port adapter or service adapter.
Each port adapter or service adapter has a bus connector that connects it to the router. The 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 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
system. 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 adapter or service adapter, the longest pins make contact with the
port adapter or service adapter first, and the shortest pins make contact last. The system recognizes the
signals and the sequence in which it receives them.
When you remove or insert a port adapter or service adapter in a Cisco 7201 router, the pins send signals
to notify the system, which then performs as follows:
1.
Rapidly scans the system for configuration changes.
2.
Initializes all newly inserted port adapters or service adapters, noting any removed interfaces and
placing them in the administratively shutdown state.
3.
Brings all previously configured interfaces on the port adapter back to the state they were in when
they were removed. Any newly inserted interface is put in the administratively shutdown state, as if
it was present (but not configured) at boot time. If a similar port adapter type is reinserted into a slot,
its ports are configured and brought online up to the port count of the original port adapter. (A
service adapter has no configurable ports.)
Environmental Monitoring and Reporting Functions
Environmental monitoring and reporting functions allow you to maintain normal system operation by
identifying and resolving adverse conditions prior to loss of operation. The environmental monitoring
functions constantly monitor the internal chassis air temperature and DC supply voltages and currents.
If conditions reach shutdown thresholds, the system shuts down to avoid equipment damage from
excessive heat. The reporting functions periodically log the values of measured parameters so that you
can retrieve them for analysis later, and the reporting functions display warnings on the console if any
of the monitored parameters exceed defined thresholds.
