ZyXEL Communications MSC1024G Series User Manual page 49

DHCP Relay Option82
The system supports DHCP relay agent82 (RFC 3046) that adds additional information to
client DHCP requests that the MSC relays to a DHCP server. It also supports adding the sub-
option 2 (Remote ID) with additional information.
DHCP Snooping
DHCP snooping allows the system to identify packets with DHCP server assigned IP
address(es) and block access of devices using unknown IP addresses on a subscriber port. You
can also manually add static IP addresses to the DHCP snooping table.
Anti-IP Address Spoofing
With DHCP snooping, a line card records which IP address is assigned to each DHCP client
MAC address and the VLAN to which each IP and MAC address pair belongs. The line card
drops packets from a device using an IP address that is assigned to a different MAC address.
Upstream Broadcast Storm Control
Broadcast storm control lets you set limits for how many broadcast, multicast and destination
lookup failure (DLF) packets a port receives per second from the subscriber.
Downstream Broadcast VLAN Control
Downstream broadcast VLAN control allows you to block downstream broadcast packets
from being sent to specified VLANs on specified ports. This helps to reduce downstream
bandwidth requirements on a subscriber line.
Cluster Management
Cluster management allows you to access the web configurators and CLIs of multiple
DSLAMs through one DSLAM, called the cluster manager. The IESs must be directly
connected and be in the same VLAN group so as to be able to communicate with one another.
Queuing
Queuing is used to help solve performance degradation when there is network congestion.
Two scheduling services are supported: Strict Priority Queuing (SPQ) and Weighted Round
Robin (WRR) Queuing. This allows the MSC to maintain separate queues for packets from
each individual source or flow and prevent a source from monopolizing the bandwidth.
Trunking
The management switch card can trunk (aggregate port links into one logical link) Gigabit
Ethernet interfaces.
Isolation (per-VLAN)
Use isolation to block the DSL subscribers in a specific VLAN from sending traffic directly to
each other. The DSL subscribers can only send and receive traffic to and from the ports that
are set to uplink mode. The Integrated Ethernet Switch blocks access between the DSL ports.
MSC1000G/1024G/1224G Series User's Guide
Chapter 1 Getting to Know Your MSC
49