Multiple Registration Protocol (MRP), which replaced Generic Attribute Registration Protocol (GARP), is a generic registration framework defined by the IEEE 802.1ak amendment to the IEEE 802.1Q standard. MRP allows
bridges
A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually someth ...
,
switches
In electrical engineering, a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. The most common type of ...
or other similar devices to register and de-register attribute values, such as
VLAN
A virtual local area network (VLAN) is any broadcast domain that is partitioned and isolated in a computer network at the data link layer ( OSI layer 2).IEEE 802.1Q-2011, ''1.4 VLAN aims and benefits'' In this context, virtual, refers to a ph ...
identifiers and
multicast
In computer networking, multicast is group communication where data transmission is addressed to a group of destination computers simultaneously. Multicast can be one-to-many or many-to-many distribution. Multicast should not be confused with ...
group membership across a large
local area network
A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building. By contrast, a wide area network (WAN) not only covers a larger ...
. MRP operates at the
data link layer
The data link layer, or layer 2, is the second layer of the seven-layer OSI model of computer networking. This layer is the protocol layer that transfers data between nodes on a network segment across the physical layer. The data link layer ...
.
History
GARP was defined by the IEEE 802.1 working group to provide a generic framework allowing bridges (or other devices like switches) to register and de-register attribute values such as VLAN identifiers and multicast group membership. GARP defines the architecture, rules of operation, state machines and variables for the registration and de-registration of attribute values. GARP was used by two applications: GARP VLAN Registration Protocol (GVRP) for registering VLAN trunking between multilayer switches, and by the GARP Multicast Registration Protocol (GMRP). The latter two were both mostly enhancements for VLAN-aware switches per definition in IEEE 802.1Q.
Multiple Registration Protocol (MRP) was introduced in order to replace GARP, with the IEEE 802.1ak amendment in 2007. The two GARP applications were also modified in order to use MRP. GMRP was replaced by Multiple MAC Registration Protocol (MMRP) and GVRP was replaced by Multiple VLAN Registration Protocol (MVRP). This change essentially moved the definitions of GARP, GVRP, and GMRP into an 802.1Q based environment, implying they were already VLAN aware. This also allowed for significant streamlining of the underlying protocol without much change to the interface of the applications themselves.
The new protocol and applications fixed a problem with the old GARP-based GVRP-based system,
where a simple registration or a failover could take an extremely long time to converge on a large network, incurring a significant bandwidth degradation.
It is expected GARP will be removed from IEEE 802.1D at some point in the future.See footnote in Annex E of IEEE 802.1ak
Multiple MAC Registration Protocol
Multiple MAC Registration Protocol is a data link layer (layer 2) protocol to register group MAC addresses (i.e. multicast) on multiple switches. It is an MRP application, originally defined in IEEE 802.1ak-2007 and subsequently included in 802.1Q. It replaced the 802.1D based GMRP. The purpose of MMRP is to allow multicast traffic in bridged LANs to be confined to areas of the network where it is required.
Multiple VLAN Registration Protocol
MVRP, which replaced GVRP, is a standards-based
Layer 2
The data link layer, or layer 2, is the second layer of the seven-layer OSI model of computer networking. This layer is the protocol layer that transfers data between nodes on a network segment across the physical layer. The data link layer p ...
network protocol
A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics and synchroniza ...
, for automatic configuration of
VLAN
A virtual local area network (VLAN) is any broadcast domain that is partitioned and isolated in a computer network at the data link layer ( OSI layer 2).IEEE 802.1Q-2011, ''1.4 VLAN aims and benefits'' In this context, virtual, refers to a ph ...
information on
switches
In electrical engineering, a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. The most common type of ...
. It was defined in the 802.1ak amendment to 802.1Q-2005.
Within a layer 2 network, MVRP provides a method to dynamically share VLAN information and configure the needed VLANs. For example, in order to add a switch port to a VLAN, only the end port, or the VLAN-supporting network device connected to the switchport, need be reconfigured, and all necessary VLAN trunks are dynamically created on the other MVRP-enabled switches. Without using MVRP, either a manual configuration of VLAN trunks or use of a manufacturer's proprietary method is necessary.
It is through MVRP that dynamic VLAN entries will be updated in the filtering database. In short, MVRP helps to maintain VLAN configuration dynamically based on current network configurations.
802.1Q allows for:
# Dynamic configuration and distribution of VLAN membership information by means of the MVRP
# Static configuration of VLAN membership information via management mechanisms, which allow configuration of static VLAN registration entries.
# Combined static and dynamic configuration, in which some VLANs are configured via management mechanisms and for other VLANs, MVRP is relied on to establish the configuration.
MVRP defines a MRP application that provides the VLAN registration service. MVRP makes use of MRP Attribute Declaration (MAD) and MRP Attribute Propagation (MAP), which provide the common state machine descriptions and the common information propagation mechanisms defined for use in MRP-based applications. MVRP provides a mechanism for dynamic maintenance of the contents of dynamic VLAN registration entries for each VLAN, and for propagating the information they contain to other bridges. This information allows MVRP-aware devices to establish and update dynamically their knowledge of the set of VLANs that currently have active members, and through which ports those members can be reached. The main purpose of MVRP is to allow switches to automatically discover some of the VLAN information that would otherwise need to be manually configured.
Legacy GVRP details
The replaced GVRP was essentially the same thing, but it used the services of the 802.1D based GARP application. GVRP made use of GARP Information Declaration (GID) and GARP Information Propagation (GIP), which correspond to the MAP and MAD in MRP. It was defined in the original release of 802.1D-1998 until it was replaced by MVRP.
It was replaced because the non-VLAN aware GARP had serious deficiencies when operating in large VLAN networks.