VLAN Advertisement Protocol (VAP)
Page 21-9

VAP and Port Policies

One of the main purposes of VAP is to advertise the connectivity of devices attached to the
switch via AutoTracker port policies. VAP eliminates the need to apply port policies to back-
bones to ensure that connectivity is established and maintained. When you use port policies,
all devices heard through a port will become a member of the VLAN. Using port policies
across backbones is not efficient because all devices learned over the backbone would be
placed in the same VLAN since they would be attached to the same port.
For this reason, port policies should not be used to interconnect switches because these poli-
cies classify MAC addresses on VLANs. Backbone ports should be left in the default VLAN, and
only learned devices should be segregated into VLANs by port policies.
There are two types of port policies (or rules), regular port rules and port forwarding rules.
Only one can be active at a time. The type of port rule is determined by a command line in
the mpx.cmd file. See Port Policy Functionality in Chapter 22, “Managing AutoTracker VLANs,”
for a detailed explanation of the two port rules settings.
Regular port policy places frames received on a particular port into a VLAN; VLAN member-
ship is based on the port. The current version of VAP supports regular port rules only.
If you set up VAP in its full mode (VLAN membership exchanges and auto-discovery), the
switch will automatically set the port policy to regular mode.
♦ Note ♦
Earlier versions of VAP include an Adjacency Only
mode. If an earlier version of VAP is running on the
switch in Adjacency Only mode, when new code is
loaded and the switch is rebooted, VAP will be set to
off. If an earlier version of VAP is set to Full mode, VAP
remains in Full mode when the new code is loaded
and the switch is rebooted.

Configuring VAP

There are two settings for the VLAN advertisement protocol, off or full mode. These modes
are defined as follows:
•Full mode—VLAN membership information exchanged between switches and auto-discov-
ery of network nodes is enabled. This option automatically sets the port policy to regular
mode.
•Off —Disables VAP exchanges. Nodes will not be auto-discovered and VLAN information
will not be exchanged between switches.
To change the VAP mode, at a UI command prompt, enter vlap and select the mode in which
you want VAP to run. A screen similar to the following displays:
The VLAN advertisement protocol is currently not running
To change the mode type: F - full mode, O - off : ( ) :
Or, enter the vlap command with the desired mode. For example:
vlap f
A message similar to the following displays:
The VLAN advertisement protocol is currently running.
The new mode takes effect immediately. You do not need to reboot the switch.