Install guide

Software Version 2.9.1 55
Software Version 2.9.1
C613-10486-00 REV C
IP Multicasting Enhancements
This Software Version includes the following enhancements to IP Multicasting:
■ PIM Support on AT-8600 Series Switches
■ Query Solicitation
This section describes the enhancements. The new and modified commands to
implement them are described in Command Reference Updates.
PIM Support on AT-8600 Series Switches
This Software Version introduces Protocol Independent Multicast (PIM) on the
AT-8600 Series switches. For information about configuring PIM on your
switch, see the IP Multicasting chapter at the end of this Release Note.
When running Software Version 2.9.1 on an AT-8600 Series switch, you will
need a special feature licence to use PIM. Contact your authorised Allied
Telesis distributor or reseller for details and passwords of feature licences.
Query Solicitation
This Software Version enhances IGMP snooping by providing the new query
solicitation feature. Query solicitation minimises loss of multicast data after a
topology change on networks that use EPSR or spanning tree (STP, RSTP, or
MSTP) for loop protection.
When IGMP snooping is enabled and EPSR or Spanning Tree changes the
underlying link layer topology, this can interrupt multicast data flow for a
significant length of time. Query solicitation prevents this by monitoring for
any topology changes. When it detects a change, it generates a special IGMP
Leave message known as a Query Solicit, and floods the Query Solicit message
to all ports in every VLAN that query solicitation is enabled on. When the
IGMP Querier receives the message, it responds by sending a General Query,
which all IGMP listeners respond to. This refreshes snooped group
membership information in the network.
Query solicitation functions by default (without you enabling it) on all VLANs
on the root bridge in an STP instance and on all data VLANs on the master
node in an EPSR instance. By default, the root bridge or master node always
sends a Query Solicit message when the topology changes.
If you have multiple STP or EPSR instances, query solicitation only sends
Query Solicit messages on VLANs in the instance that experienced a topology
change.
In switches other than the STP root bridge or EPSR master node, query
solicitation is disabled by default, but you can enable it by using the command:
set igmpsnooping vlan={vlan-name|1..4094|all}
querysolicit={on|yes|true}
If you enable query solicitation on a switch other than the STP root bridge or
EPSR master node, both that switch and the root or master send a Query Solicit
message.