Relaying Dhcp Packets That Originate From A Cable Modem; Configuring Relay Agent Option 82 Information - Juniper JUNOSE 11.1.X - BROADBAND ACCESS CONFIGURATION GUIDE 6-4-2010 Configuration Manual

JUNOSe 11.1.x Broadband Access Configuration Guide

Relaying DHCP Packets That Originate from a Cable Modem

You can use the DHCP vendor class identifier option (option 60) to configure DHCP
relay to relay DHCP packets that originate from a cable modem to an external DHCP
server that provides the cable modem with the configuration it requests.
Configure the vendor class identifier option to match the string used by cable
modems DHCP relay then forwards the packets to each DHCP server that you
configured with the set dhcp vendor-option command (these servers are also
considered to be cable-modem DHCP servers).

Configuring Relay Agent Option 82 Information

You can specify the type the relay agent option 82 information that the router adds
to DHCP packets before it relays the packets to the DHCP server. You can use one
of the following keywords to add either the hostname or virtual router name to the
front of the Circuit-Id field or to strip the subinterface ID from the Interface-Id field:
506
Configuring DHCP Relay and BOOTP Relay
* - the configured vendor-string is an exact-match
default - all DHCP client packets not matching a configured vendor-string
implied - the DHCP application is configured but has not been enabled
with the vendor-option command
drop - the DHCP application responsible for the action has not been
configured yet therefore all packets for this application
will be dropped
Total 3 entries.
Vendor-option
-------------------------------- ----------------------------------------
abcd
default(*)
myword(*)
To relay DHCP packets from a cable modem:
host1(config)#set dhcp relay
host1(config)#service dhcp-local equal-access
host1(config)#set dhcp vendor-option equals docsis relay 192.168.1.1
host1(config)#set dhcp vendor-option equals cablemodem relay 192.168.1.1
Use the show dhcp summary and show dhcp vendor-option commands to display
information about the cable modem DHCP relay configuration. See "Monitoring
and Troubleshooting DHCP" on page 539.
hostname Adds the router's hostname to the front of the Circuit-Id field; a
colon separates the hostname from the circuit information
vrname Adds the router's virtual router name to the front of the Circuit-Id field;
a colon separates the virtual router name from the circuit information
Use the exclude-subinterface-id to strip the subinterface ID from the Interface-Id
field. When the interface ID is constructed, it contains the slot/port numbers,
the subinterface ID, and the VPI/VCI for ATM interfaces or the VLAN ID for
Action
relay to 192.168.15.2 (rx: 0)
local-server (rx: 0, no-match: 0)
relay to 192.168.7.7 (rx: 0)