ZyXEL Communications ALC1248G, User Manual

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Chapter 1 Introducing the ALC1248G
ALC1248G User’s Guide
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Multicast VLAN
Multicast VLAN is designed for applications (such as Media-on-Demand (MoD)) using
multicast traffic across an Ethernet ring-based service provider network. Multicast VLAN
allows one single multicast VLAN to be shared among different subscriber VLANs on the
network. This improves bandwidth utilization by reducing multicast traffic in the subscriber
VLANs and simplifies multicast group management.
IEEE 802.1x Port-based Authentication
The ALC supports the IEEE 802.1x standard for centralized user authentication and
accounting management through an optional network authentication (RADIUS) server.
Port Isolation
The ALC's port isolation feature allows each port to communicate with the uplink port but not
communicate with each other. This option is the most limiting but also the most secure.
Isolation (per-VLAN)
Use isolation to block the DSL subscribers in a specific VLAN from sending traffic directly to
each other.
Packet Filter
The ALC supports packet filtering based on protocol. You can configure the ALC to accept all
packets, accept PPPoE packets only or block any combination of the following protocols: IP,
ARP, DHCP, EAPOL, PPPoE, NetBios or IGMP.
MAC (Media Access Control) Filters
Use the MAC filter to filter incoming frames based on MAC (Media Access Control)
address(es) or the OUI (Organizational Unit Identifier) that you specify. You may enable/
disable the MAC filter on specific ports. You may specify up to ten MAC addresses per port.
MAC (Media Access Control) Count Limit
You can limit the number of MAC addresses that may be dynamically learned on a port. You
may enable/disable the MAC count limit on individual ports.
IGMP Snooping
The ALC supports IGMP snooping enabling group multicast traffic to be only forwarded to
ports that are members of that group; thus allowing you to significantly reduce multicast
traffic passing through your ALC.
IGMP Filter
The IGMP filter defines multicast groups a port can join. You can create IGMP filter profiles
which allow access to a multicast group, then assign the IGMP filter to a specific DSL port.
Multicast Group Limit
You can limit the number of IGMP multicast groups a subscriber on a port can join. You may
enable/disable the multicast group limit on individual ports.