Chapter 8: Virtual LANs and GVRP
122 Section I: Using the Menus Interface
GVRP
This section describes GVRP and contains the following topics:
“GVRP Overview,” next
“Enabling or Disabling GVRP” on page 123
GVRP Overview The GARP VLAN Registration Protocol (GVRP) allows network devices to
share VLAN information. The main purpose of GVRP is to allow switches
to automatically discover some of the VLAN information that would
otherwise need to be manually configured in each switch. This is helpful in
networks where VLANs span more than one switch. Without GVRP, you
must manually configure your switches to ensure that the various parts of
a VLAN can communicate across the different switches. GVRP, which is
an application of the Generic Attribute Registration Protocol (GARP), does
this for you automatically.
Figure 31 provides an example of how the GVRP feature works:
Figure 31. GVRP Example
Switches 1 and 3 contain the Sales VLAN, but switch 2 does not.
Consequently, the end nodes of the two parts of the Sales VLANs are
unable to communicate with each other.
Without GVRP, you would need to configure switch 2 by creating a Sales
VLAN on the switch and adding ports 2 and 3 as members of the VLAN. If
you have a large network and a large number of VLANS, this type of
manual configuration can be cumbersome and time consuming. Instead,
let GVRP set up the communications path for you.
Guidelines Following are guidelines to observe when you use GVRP:
Both ports that constitute a data link between the switch and the other
device must be running GVRP.
You cannot modify a GVRP VLAN; you can only enable or disable it.
793
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Port 1
Port 2
Port 4
Port 3
Switch #3
Static VLAN
Sales VID=11
Switch #1
Static VLAN
Sales VID=11
Switch #2
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AT-9000/24
24 Port Gigabit Ethernet Switch
13579111315
171921R23R
246 8101214 16 18 20 22R 24R
POWER
2122
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LINK ACT
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PORT ACTIVITY
793
AT-9000/24
24 Port Gigabit Ethernet Switch
13579111315
171921R23R
246 8101214 16 18 20 22R 24R
POWER
2122
2324
SFP
LINK ACT
1000
10/100
PORT ACTIVITY