Chapter 7 VLAN
7.2 Automatic VLAN Registration
GARP and GVRP are the protocols used to automatically register VLAN membership across switches.
7.2.1 GARP
GARP (Generic Attribute Registration Protocol) allows network switches to register and deregister attribute values with other GARP participants within a bridged LAN. GARP is a protocol that provides a generic mechanism for protocols that serve a more specific application, for example, GVRP.
7.2.1.1 GARP Timers
Switches join VLANs by making a declaration. A declaration is made by issuing a Join message using GARP. Declarations are withdrawn by issuing a Leave message. A Leave All message terminates all registrations. GARP timers set declaration timeout values.
7.2.2 GVRP
GVRP (GARP VLAN Registration Protocol) is a registration protocol that defines a way for switches to register necessary VLAN members on ports across the network. Enable this function to permit VLANs groups beyond the local switch.
Table 17 IEEE 802.1Q Terminology
VLAN PARAMETER | TERM | DESCRIPTION |
VLAN Type | Permanent VLAN | This is a static VLAN created manually. |
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| Dynamic VLAN | This is a VLAN configured by a GVRP registration/ |
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| deregistration process. |
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VLAN Administrative | Registration Fixed | Fixed registration ports are permanent VLAN members. |
Control |
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| Registration | Ports with registration forbidden are forbidden to join the |
| Forbidden | specified VLAN. |
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| Normal Registration | Ports dynamically join a VLAN using GVRP. |
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VLAN Tag Control | Tagged | Ports belonging to the specified VLAN tag all outgoing |
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| frames transmitted. |
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| Untagged | Ports belonging to the specified don't tag all outgoing |
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| frames transmitted. |
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VLAN Port | Port VID | This is the VLAN ID assigned to untagged frames that |
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| this port received. |
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| Acceptable frame | You may choose to accept both tagged and untagged |
| type | incoming frames or just tagged incoming frames on a |
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| port. |
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| Ingress filtering | If set, the switch discards incoming frames for VLANs |
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| that do not have this port as a member |
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