3com S7906E Instrução De Instalação

 

1-10 

When a loop is detected on an access port, the device operates on the port according to the 

pre-configured loopback detection actions, sends trap messages and log information to the terminal, 

and deletes the corresponding MAC address forwarding entry. 

When a loop is detected on a trunk port or a hybrid port, the device sends trap messages and log 

information to the terminal. If loopback detection control is also enabled on the port, the device operates 

on the port according to the pre-configured loopback detection actions, sends trap messages and log 

information to the terminals, and deletes the corresponding MAC address forwarding entry. 

Follow these steps to configure loopback detection: 

Enter system view 

system-view — 

Enable global loopback 
detection 

Required 

Disabled by default 

Configure the interval for port 
loopback detection 

loopback-detection 
interval-time time 

Optional 

30 seconds by default 

Enter 
Ethernet port 
view 

interface interface-type 
interface-number 

Enter 
Ethernet port 
view or port 
group view 

Enter port 
group view 

port-group manual 
port-group-name 

Use either command 
Configurations made in 
Ethernet port view takes effect 
on the current port only; 
configurations made in port 
group view takes effect on all 
ports in the port group 

Enable loopback detection on a 
port 

Required 

Disabled by default 

Enable loopback detection 
control on a trunk port or a 
hybrid port 

loopback-detection control 
enable 

Optional 

Disabled by default 

Enable loopback detection in all 
the VLANs to which trunk or 
hybrid ports belong 

Optional 

Enabled only in the default 
VLAN(s) with trunk port or 
hybrid ports 

Specify actions to be taken on a 
port when a loop is detected on 
it 

loopback-detection action 
{ shutdown | semi-block | 
no-learning } 

Optional 

By default, the port does not 
specify loopback detection 
actions. 

 

z 

Loopback detection on a given port is enabled only after the loopback-detection enable 

command has been configured in both system view and the port view of the port. 

z 

Loopback detection on all ports will be disabled after you configure the undo loopback-detection 

enable command in system view. 

z 

For loopback detection actions to take effect on a trunk or hybrid port, you need to configure the 

loopback-detection control enable command in the port view of the port.