Allied Telesis AT-S63 - Manual (Page 290)

Chapter 25: GARP VLAN Registration Protocol
290 Section VI: Virtual LANs
GVRP-inactive Intermediate Switches
If two GVRP-active devices are separated by a GVRP-inactive switch, the
GVRP-active devices may not be able to share VLAN information. There
are two issues involved.
The first is whether the intermediate switch forwards the GVRP PDUs that
it receives from the GVRP-active switches. GVRP PDUs are management
frames, intended for a switch’s CPU. In all likelihood, a GVRP-inactive
switch will discard the PDUs because it does not recognize them.
The second issue is that even if the GVRP-inactive switch forwards GVRP
PDUs, it will not create the VLANs, at least not automatically.
Consequently, even if the GVRP-active switches receive the PDUs and
create the necessary VLANs, the intermediate switch may block the VLAN
traffic, unless you modify its VLANs and port assignments manually.