Figure 10-14 Dhcp Relay Agent Circuit Id Sub-Option Format - ZyXEL Communications IES-1000 User Manual

LABEL
Member Ports This field displays the ports that belong to this multicast group, E=Ethernet, 1~8 = ADSL
ports 1 through 8.
Refresh Click this button to update the multicast filtering record.
FlushAll Click this button to clear the multicast filtering record.
10.5.8 DHCP Relay
DHCP (Dynamic Host Configuration Protocol, RFC 2131 and RFC 2132) allows individual clients to obtain
TCP/IP configuration at start-up from a DHCP server. You can configure the Integrated Ethernet Switch to relay
client TCP/IP configuration requests to a DHCP server and the server's responses back to the clients.
10.5.9 DHCP "Relay Agent Information Option"
The Integrated Ethernet Switch can add information to client TCP/IP configuration requests that it relays to a
DHCP server. This helps provide authentication about the source of the requests. You can also specify additional
information for the Integrated Ethernet Switch to add to the client TCP/IP configuration requests that it relays to
the DHCP server. Please refer to RFC 3046 for more details.
10.5.10 DHCP Relay Agent Circuit ID Sub-option Format
The DHCP relay agent information feature adds an Agent Information field to the option 82 field of the DHCP
headers of client TCP/IP configuration request frames that the Integrated Ethernet Switch relays to a DHCP
server. The Agent Information field that the Integrated Ethernet Switch adds contains an "Agent Circuit-ID sub-
option" that includes the slot ID, port number, VLAN ID and optional information about the port where the
TCP/IP configuration request was received.
The following figure shows the format of the Agent Circuit ID sub-option. The 1 in the first field identifies this as
an Agent Circuit ID sub-option. If the configuration request was received on a network module's port, a 1-byte
Slot ID field specifies the slot location of the network module in the Integrated Ethernet Switch and a 1-byte Port
No field specifies the ingress port number. The next field is 2 bytes and displays the DHCP request packet's
VLAN ID. The last field (A) can range from 0 to 24 bytes and is optional information (that you specify) about this
relay agent.

Figure 10-14 DHCP Relay Agent Circuit ID Sub-option Format

Getting Started Screens
Table 10-12 Bridge IGMP Snooping Record
DESCRIPTION
IES-1000 User's Guide
10-15