Hirschmann GREYHOUND GRS1020, Reference Manual

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Advanced functions of the device
14.4 MRP-IEEE
229
UM Config GRS
Release 8.0 09/2019
14.4 MRP-IEEE
The IEEE 802.1ak amendment to the IEEE 802.1Q standard introduced the Multiple Registration
Protocol (MRP) to replace the Generic Attribute Registration Protocol ( GARP ). The IEEE also
modified and replaced the GARP applications, GARP Multicast Registration Protocol ( GMRP ) and
GARP VLAN Registration Protocol ( GVRP ), with the Multiple MAC Registration Protocol ( MMRP ) and
the Multiple VLAN Registration Protocol ( MVRP ).
To confine traffic to the required areas of a network, the MRP applications distribute attribute values
to MRP enabled devices across a LAN. The MRP applications register and de-register Multicast
group memberships and VLAN identifiers.
Note: The Multiple Registration Protocol (MRP) requires a loop free network. To help prevent loops
in your network, use a network protocol such as the Media Redundancy Protocol, Spanning Tree
Protocol, or Rapid Spanning Tree Protocol with MRP.
14.4.1 MRP operation
Each participant contains an applicant component and an MRP Attribute Declaration (MAD)
component. The applicant component is responsible for forming the attribute values and their
registration and de-registration. The MAD component generates MRP messages for transmission
and processes messages received from other participants. The MAD component encodes and
transmits the attributes to other participants in MRP Data Units (MRPDU). In the switch, an MRP
Attribute Propagation (MAP) component distributes the attributes to participating ports.
A participant exists for each MRP application and each LAN port. For example, a participant
application exists on an end device and another application exists on a switch port. The Applicant
state machine records the attribute and port for each MRP participant declaration on an end device
or switch. Applicant state machine variable changes trigger the transmission of MRPDUs to
communicate the declaration or withdrawal.
To establish an MMRP instance, an end device first sends a Join empty (JoinMt) message with the
appropriate attributes. The switch then floods the JoinMt to the participating ports and to the
neighboring switches. The neighboring switches flood the message to their participating port, and
so on, establishing a path for the group traffic.
14.4.2 MRP timers
The default timer settings help prevent unnecessary attribute declarations and withdraws. The
timer settings allow the participants to receive and process MRP messages before the Leave or
LeaveAll timers expire.
When you reconfigure the timers, maintain the following relationships:

To allow for re-registration after a Leave or LeaveAll event, although there is a lost message,
set the value of the LeaveTime as follows: ≥ (2x JoinTime) + 60 in 1/100 s

To minimize the volume of rejoining traffic generated following a LeaveAll, specify the value for
the LeaveAll timer larger than the LeaveTime.