ZyXEL Communications 1 - Manual (Page 99)

NetAtlas Enterprise 1.00 User’s Guide
Chapter 11 Switch Configuration 98
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H A P T E R
11
Switch Configuration
This chapter shows how to configure priority queuing, STP, link aggregation, DHCP relay,
GARP timer and RADIUS.
11.1 IGMP Snooping
IGMP (Internet Group Multicast Protocol) is a session-layer protocol used to establish
membership in a multicast group - it is not used to carry user data. Refer to RFC 1112 and
RFC 2236 for information on IGMP versions 1 and 2 respectively.
A layer-2 switch can passively snoop on IGMP Query, Report and Leave (IGMP version 2)
packets transferred between IP multicast routers/switches and IP multicast hosts to learn the IP
multicast group membership. It checks IGMP packets passing through it, picks out the group
registration information, and configures multicasting accordingly.
Without IGMP snooping, multicast traffic is treated in the same manner as broadcast traffic,
that is, it is forwarded to all ports. With IGMP snooping, group multicast traffic is only
forwarded to ports that are members of that group. IGMP Snooping generates no additional
network traffic, allowing you to significantly reduce multicast traffic passing through your
switch.
11.2 Switch Setup
Use the switch setup screen to set a VLAN type, a queuing method and enable or disable
features in the Active Control panel.
1 In the Device Panel list, select a device and then right-click.
2 Click Configuration, Switch Configuration and then the Switch Setup tab.
The VLAN setup screens change depending on whether you choose 802.1Q or Port Based in
the VLAN Type field in this screen. Refer to
Section 13.2 on page 126 for more information.