Znyx Networks bh5700 - Manual (Page 325)

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. Based on monitored IGMP traffic, zsnoopd
creates or updates an entry in the table. The key to each 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 table is reached, zsnoopd deletes a random entry
prior to adding the next entry.
The Ethernet Switch Blade does not perform Multicast routing, but 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 325