During the network discovery stage, the 7705 SAR sends a DHCP DISCOVER message from all operational ports. Table: DHCP DISCOVER Message Options describes the DHCP DISCOVER message options.
|
Option |
Name |
Description |
|---|---|---|
|
chaddr |
Client HW Address |
The MAC address of the port |
|
51 |
Lease Time |
Always set to Infinite |
|
60 |
Class Identifier |
The class of 7705 SAR router: ALU-AD | SAR-8 ALU-AD | SAR-18 ALU-AD | SAR-A ALU-AD | SAR-Ax ALU-AD | SAR-H ALU-AD | SAR-Hc ALU-AD | SAR-M ALU-AD | SAR-Wx ALU-AD | SAR-X |
|
61 |
Client Identifier |
Not sent by default, but can be configured to be the chassis MAC address or an operator-defined string |
|
82 |
Relay Agent Information |
Network uplink information, such as circuit ID and gateway address, added by the relay agent, if applicable |
No client identifier is sent by default, but you can configure this option during boot-up, or with the auto-discover command, to be the chassis MAC address or a unique string. During boot-up, you can also configure the VLAN ID for ADP with dot1q or qinq encapsulation.
The ADP network discovery phase is enhanced to automatically scan the entire VLAN range on every datapath Ethernet port on supported cards and nodes. During startup a new node acts as an ADP client and send DHCP discovery packets across the entire VLAN range to automatically discover the Ethernet virtual connection (EVC) VLAN. If at least one DHCP discovery packet reaches a server and that server responds with a DHCP offer packet, the ADP client node registers the new interface against that server's VLAN.