Specifications

cGVRP
Information About cGVRP
3
In Compact GVRP a GVRP PDU may be sent out the port if the port is in forwarding state in a spanning
tree instance. GVRP PDUs must be transmitted in the native VLAN of .1Q trunks.
GVRP Interoperability with VTP and VTP Pruning
VTP Pruning is an extension of VTP. It has its own Join message that can be exchanged with VTP PDUs.
VTP PDUs can be transmitted on both .1Q trunks and ISL trunks. A VTP capable device is in either one
of the three VTP modes: Server, Client, or Transparent.
When VTP Pruning and GVRP are both enabled globally, VTP Pruning is run on ISL trunks, and GVRP
is run on .1Q trunks.
Compact GVRP has two modes: Slow Compact Mode, and Fast Compact Mode. A port can be in Fast
Compact Mode if it has one GVRP enabled peer on the same LAN segment, and the peer is capable of
operating in Compact Mode. A port is in Slow Compact Mode if there are multiple GVRP participants
on the same LAN segment operating in Compact Mode.
GVRP interoperability with Other Software Features and Protocols
STP
Spanning Tree Protocol (STP) may run in one of the three STP modes: Multiple Spanning Tree(MST),
Per VLAN Spanning Tree (PVST), or Rapid PVST. An STP mode range causes the forwarding ports to
leave the forwarding state as STP has to reconverge. This may cause GVRP to have its own topology
change as Join messages my be received on some new ports and Leave timers may expire on some others.
DTP
DTP negotiates the port mode (trunk vs. non-trunk) and the trunk encapsulation type between two DTP
enabled ports. After negotiation DTP may set the port to either ISL trunk, or .1Q trunk, or non trunk.
DTP negotiation occurs after ports become link-up and before they become forwarding in spanning trees.
If GVRP is administratively enabled on a port and the device, it should be initialized after the port is
negotiated to be a .1Q trunk.
VTP
VTP version 3 expands the range of VLANs that can be created and removed via VTP. VTP Pruning is
available for VLAN 1 - 1005 only.
EtherChannel
When multiple .1Q trunk ports are grouped by either Port Aggregation Protocol (PAgP) or Link
Aggregation Control Protocol (LACP) to become an etherchannel, the etherchannel can be configured
as a GVRP participant. The physical ports in the etherchannel cannot be GVRP participants by
themselves. Since an etherchannel is treated like one virtual port by STP, the GVRP application can learn
the STP state change of the etherchannel just like any physical port. The etherchannel, not the physical
ports in the channel, constitutes the GARP Information Propagation (GIP) context.