Alcatel Carrier Internetworking Solutions Switch/Router 用户手册

Page 22-5

When a broadcast frame, a multicast frame, or a unicast frame from an unknown device is 
received at a switching module, the frame is forwarded to the 

MPX

 for processing. Source 

learning logic on the 

MPX

 module examines the entire frame to determine the 

VLAN

 or 

VLAN

s 

in which the originating device should be a member. If the frame matches any one policy 
defined for a 

VLAN

, the originating device (and the port to which it is connected) are made 

members of that 

VLAN

. If the frame does not match any 

VLAN

 policy, one of the following 

occurs:

• If the 

 command is on, the source device is made a member of Default 

VLAN

 #1 in the 

Group of which the source port is a member. The 

 command determines whether traf-

fic from devices that do not match any policies is assigned to the default 

VLAN

 or dropped. 

(See “The defvl Command” below for more information on this command.)

• If the 

 command is off, all traffic from the source device is dropped.

A broadcast or multicast frame is processed to 
determine the source device’s 

VLAN

 membership 

each time it is received. A unicast frame is 
processed to determine the source device’s 

VLAN

 

membership only the first time it is received.

When the 

MPX

 module has determined the 

VLAN

 or 

VLAN

s in which the originating device 

belongs, it relays this information to the switching module. The switching module updates a 

VLAN

 membership flag attached to the frame’s source 

MAC

 address in the 

CAM

 (content-

addressable memory). The frame is then switched based on this membership flag.

Refer to Chapter 24, “AutoTracker VLAN Application Examples,” for information on 
AutoTracker 

VLAN

 assignments in specific network situations.

You can turn the 

 command on and off simply by entering 

 or 

. If you 

enter the command without any parameters, it displays the current setting for the Default 

VLAN

. For example, if source devices are automatically placed in the Default 

VLAN

 when they 

do not match any 

VLAN

 policy rule, the following message would display:

If source devices are automatically dropped when they do not match any 

VLAN

 policy, the 

following message would display:

The 

 command applies to all Groups in an Omni Switch/Router and it is only applicable 

if there is at least one AutoTracker rule configured.