Alcatel Carrier Internetworking Solutions Switch/Router 用户手册

Page 24-8

AutoTracker “activates” a 

VLAN

 – and its internal router interface – when the first port is 

assigned to the 

VLAN

. If a 

VLAN

 has a port policy, AutoTracker assigns the specified port(s) 

and activates the 

VLAN

 immediately. If a 

VLAN

 has a logical policy, AutoTracker assigns the 

first port to the 

VLAN

 when a frame is received from a source device that matches the 

VLAN

’s 

policy. When such a frame is received, the source device – and the port to which that device 
is connected – are assigned to the 

VLAN

 and the 

VLAN

 is activated. 

Until a port is assigned to a 

VLAN

, that 

VLAN

 is maintained in an inactive state and its internal 

router port is inactive – even if routing was enabled by the user. Use of a 

VLAN

’s routing 

service is “on-demand” and AutoTracker does not enable routing until a port is present that 
might require it. When AutoTracker assigns the first port to a particular 

VLAN

, it activates that 

VLAN

 and its routing service (as long as routing was enabled by the user).

Once AutoTracker has established devices’ 

VLAN

 assignments and activated the appropriate 

VLAN

 routing services, it does not participate in the routing process. Routing works correctly 

as long as the policies of the 

IPX

 protocol were followed – with the exception below.

There is one scenario in which AutoTracker affects the behavior of an 

IPX

-routed network. 

This situation occurs when an 

IPX

 server is a member of any 

VLAN

 with 

IPX

 network address 

policies 

 

IPX

 routing is enabled on the Group’s default 

VLAN

 #1. An exception condition 

arises in this situation because all ports in a Group are always members of that Group’s default 

VLAN

 #1 in addition to any other 

VLAN

s of which they are members. As a result, default 

VLAN

 

#1 is always active.

The figure on the facing page illustrates this problem situation. In this figure, three 

VLAN

s 

within Group 2 – one of which is default 

VLAN

 #1 – have 

IPX

 routing enabled, as indicated by 

the presence of the internal 

IPX

 router. 

VLAN

s 2 and 3 both have 

IPX

 network address poli-

cies. When 

IPX

 Server A is connected to the Omni Switch/Router on port 1, the Server is 

assigned to 

VLAN

 2 (per the network address policy) and port 1 becomes a member of 

VLAN

 

2. When 

IPX

 Server B is connected to the Omni Switch/Router on port 2, the Server is 

assigned to 

VLAN

 3 (per the network address policy) and port 2 becomes a member of 

VLAN

 

3. However, ports 1 and 2 are also members of the Group’s default 

VLAN

 #1, so port 1 is now 

a member of 

VLAN

 1 and 

VLAN

 2 and port 2 is now a member of 

VLAN

 1 and 

VLAN

 3. 

When 

IPX

 Server A sends broadcasts, they are restricted to 

VLAN

 2 because of the network 

address policies. When 

IPX

 Server B sends broadcasts, they are restricted to 

VLAN

 3, also 

because of the network address policies. However, when the internal 

IPX

 router sends out 

broadcasts on 

VLAN

 1 the broadcasts are flooded out all ports in the Group, because all ports 

in the Group are, by default, members of 

VLAN

 1. 

IPX

 Server A responds to this with a router 

configuration error because it is receiving broadcasts on 

VLAN

 1 when it should only receive 

them on 

VLAN

 2. 

IPX

 Server B also responds with a router configuration error because it is 

receiving broadcasts on 

VLAN

 1 when it should only receive them on 

VLAN

 3.

The solution for this problem is to disable 

IPX

 routing on default 

VLAN

 #1. Because of this, 

when your network includes 

IPX

 servers that are members of 

IPX

 network address 

VLAN

s and 

IPX

 routing is enabled, you should configure your network such that disabling 

IPX

 routing on 

default 

VLAN

 #1 is not a problem.