Znyx Networks bh5700 - Manual (Page 244)

zsnoopd
NAME
zsnoopd - IGMP Snooping daemon for the OpenArchitect switch.
SYNOPSIS
zsnoopd [-d <level>] [-f] [-h <hostname>] [-p <ppa>]
[-r <sec>] [-t <sec>] [-u <sec>] [-v <vlan_id>]
DESCRIPTION
zsnoopd is run after the network interfaces are created and initialized with zconfig, and
started with ifconfig(1M).zsnoopd starts a background task that monitors incoming IGMP
traffic in order to learn which hosts in a VLAN are listening to which IP multicast addresses.
zsnoopd updates the multicast table in silicon with this information, so that IP multicast traffic
is forwarded only to the ports in a VLAN to which listening hosts are attached. This optimizes
packet flow through the switch. Traffic on all VLANs is monitored by default. IGMP snooping
can be restricted to specific VLANs using the –v option. The background task started by
zsnoopd continues throughout the life of the Layer 2 network.
zsnoopd manages the switch multicast table (MARL). Based on monitored IGMP traffic,
zsnoopd creates or updates 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.
When the maximum number of entries in the MARL is reached, zsnoopd deletes a random
entry prior to adding the next entry.
Traffic from IP multicast addresses not found in the multicast table is forwarded to all ports
within a VLAN. Traffic from reserved IP multicast addresses (224.0.0.X) is forwarded on all
ports within a VLAN.
To operate correctly, traffic from unregistered IP multicast addresses should be forwarded on all
ports in a VLAN. To do this, the multicast port filtering mode must be set to
FORWARD_UNREGISTERED. See zconfig.
Neither zgmrpd nor zgvrpd can run concurrently with zsnoopd.
OPTIONS
-d <level> Sets the level of debugging output required by
zsnoopd. The default level is zero (0). Setting the debug
level higher produces more output. Four (4) is currently the
maximum output level.
Ethernet Switch Blade User's Guide release 3.2.2j page 244