Setting Ethernet And Fast Ethernet Port Debounce Timers - Cisco WS-C2948G-GE-TX Configuration Manual

Configuring Ethernet and Fast Ethernet Ports

Setting Ethernet and Fast Ethernet Port Debounce Timers

You can set the port debounce timer on a per-port basis for Ethernet, Fast Ethernet, and Gigabit Ethernet
ports. When you set the port debounce timer, the switch delays notifying the main processor of a link
down; this delay in notification can decrease traffic loss due to network reconfiguration.
Enabling the port debounce timer will delay link-up and link-down detections, resulting in loss of data
Caution
traffic during the debouncing period. This situation might delay the convergence and reconvergence of
various Layer 2 and Layer 3 protocols.
Table 4-2
before and after the switch enables the debounce timer.
Table 4-2
Port Type
10/100 ports
100BASE-FX ports
10/100/1000BASE-TX ports
Gigabit TX ports
Fiber Gigabit ports
To set the debounce timer on a port, perform this task in privileged mode:
Task
Step 1
Enable the debounce timer for a port.
Step 2 Verify that the debounce timer of the port is
configured correctly.
This example shows how to enable the debounce timer for module 2 on port 1:
Console> (enable) set port debounce 2/1 enable
Debounce is enabled on port 2/1
Warning: Enabling port debounce causes Link Up/Down detections to be delayed.
It results in loss of data traffic during debouncing period, which might
affect the convergence/reconvergence of various Layer 2 and Layer 3 protocols.
Use with caution.
Console> (enable)
Catalyst 4500 Series, Catalyst 2948G, Catalyst 2948G-GE-TX, and Catalyst 2980G Switches Software Configuration Guide—Release 8.2GLX
4-6
lists the time delay that occurs before the switch notifies the main processor of a link down
Switch Notification Delays for the Port Debounce Timer
Delay Time
With Debounce
Timer Disabled
0 ms
0 ms
0 ms
0 ms
0 ms
Chapter 4 Configuring Ethernet and Fast Ethernet Switching
With Debounce Timer Enabled
3.1 sec
3.1 sec
3.1 sec
3.1 sec
3.1 sec
The delay time is the time
Note
that the port is physically
down, and once the port is up,
the time the software needs to
complete autonegotiation.
Command
set port debounce
mod num/port num {enable | disable}
show port debounce [mod | mod_num/port_num]
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