Znyx Networks bh5700 - Manual (Page 295)

zgmrpd
NAME
zgmrpd - GARP Multicast Registration Protocol (GMRP) daemon for the OpenArchitect switch.
(Partially supported in this release.)
SYNOPSIS
zgmrpd [-d <level>] [-f] [-h <hostname>] [-p <ppa>] [-t <target>]
DESCRIPTION
zgmrpd is run after the network interfaces are created and initialized with zconfig, and started
with ifconfig(1M).zgmrpd starts a background task that implements the GARP Multicast
Registration Protocol (GMRP) protocol for a specified interface, either a zhp or bzhp. GMRP
provides a Layer-2 mechanism for determining which ports in a VLAN are listening to which
multicast addresses. zgmrpd updates the multicast table in silicon with this information, so that
the multicast traffic is forwarded only to the ports in a VLAN to which listening hosts are
attached. This optimizes packet flow through the switch. The background task started by
zgmrpd continues throughout the life of the Layer 2 network. GMRP is specified in ANSI/IEEE
Std 802.1D, 1998 Edition.
zgmrpd manages the switch multicast table (MARL). Based on GMRP packets received on the
target interface, zgmrpd creates, updates, or deletes an entry in the MARL. The key to each
MARL entry is a source Ethernet multicast address combined with a VLAN ID. Two port
bitmaps are maintained: one that identifies the untagged members of the VLAN, and one which
identifies which ports of the VLAN have listening hosts attached.
NOTE: OpenArchitect does not tag BPDU packets. This means that if a port belongs to
multiple VLANs, exactly which Multicast MAC/VLAN entry to create, modify, or delete
cannot be determined. GMRP should not be used when ports belong to multiple VLANs. If
the target is a zhp, it’s recommended that the zhp contain all the ports on the switch.
When the maximum number of entries in the MARL is reached, zgmrpd deletes a random entry
prior to adding the next entry.
By default, while GMRP is running, unregistered multicast traffic is filtered on the target
interface. The GMRP protocol provides a mechanism for changing the filtering behavior on a per-
port basis. Filtering behavior can be set to filter unregistered multicast traffic, forward
unregistered multicast traffic, or forward all traffic. zconfig can be used to set the filtering
mode of each port. See zconfig . Ports connected to routers should be set to “Forward All”
filtering mode manually with zconfig after zgmrpd is up and running. When zgmrpd is
terminated, filtering behavior is set to forward unregistered multicast traffic on each port in the
target interface.
Ethernet Switch Blade User's Guide release 3.2.2j page 295