Installation and Getting Started Guide
NOTE: DHCP assist applies only to HP switches. To configure an HP routing switch to assist DHCP packets,
use the UDP Helper feature. See "User Datagram Protocol (UDP) Helper" on page 7-24.
See the "Configuring IP" chapter in the Advanced Configuration and Management Guide for information on
configuring DHCP assist.
IP Multicast Containment
IP multicast containment allows the HP 6208M-SX to limit switching of IP multicast packets to only those ports
on the switch that are identified as IP multicast members. The HP 6208M-SX can provide IP multicast
containment in either of the following modes:
Passive – The switch listens for Internet Group Membership Protocol (IGMP) packets and forwards them to
the appropriate ports.
Active – The switch actively sends out host queries to identify IP multicast groups on the network and inserts
this information into the IGMP packets.
Routers in the network generally handle host queries. Unless your configuration does not contain a router to
provide this service, use IP multicast containment in the passive mode.
Layer 3 Switching Features
The following sections describe the Layer 3 switching features listed in Table 7.1 on page 7-1.
Protocol-Based Virtual LANs (VLANs)
Protocol and sub-net based VLANs increase network performance and provide managers with a high degree of
With sub-net VLANs, devices with a common sub-net can be resident across multiple ports of an HP device. This
increases performance by providing a greater pool of bandwidth for all devices.
Protocol VLANs enable managers to easily and transparently group like protocols into a defined VLAN. This
reduces the number of non-essential broadcasts on other ports and allows a port to belong to multiple VLANs
without VLAN tagging.
You can define Layer 3 VLANs for the following protocols:
IPX network number
AppleTalk cable range
For more details on the value and configuration of VLANs, see the "Configuring Virtual LANs (VLANs)" chapter in
the Advanced Configuration and Management Guide.
Routing Between VLANs
In addition to supporting the assignment of VLANs, HP routing switches support routing between VLANs using
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