ES-2108/ES-2108-G User’s Guide
60 Chapter 7 Basic Setting
In MTU (Multi-Tenant Unit) applications, VLAN is vital in providing isolation and security
among the subscribers. When properly configured, VLAN prevents one subscriber from
accessing the network resources of another on the same LAN, thus a user will not see the
printers and hard disks of another user in the same building.
VLAN also increases network performance by limiting broadcasts to a smaller and more
manageable logical broadcast domain. In traditional switched environments, all broadcast
packets go to each and every individual port. With VLAN, all broadcasts are confined to a
specific broadcast domain.
Note: VLAN is unidirectional; it only governs outgoing traffic.
See Chapter 8 on page 67 for information on port-based and 802.1Q tagged VLANs.
7.5 IGMP Snooping
A 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. IGMP snooping allows the
switch to learn multicast groups without you having to manually configure them.
The switch forwards multicast traffic destined for multicast groups (that it has learned from
IGMP snooping or that you have manually configured) to ports that are members of that
group. The switch discards multicast traffic destined for multicast groups that it does not
know. IGMP snooping generates no additional network traffic, allowing you to significantly
reduce multicast traffic passing through your switch.
7.6 Switch Setup Screen
Click Basic Setting and then Switch Setup in the navigation panel to display the screen as
shown. 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 the chapter on VLAN.
