VLAN discovery

The node can perform VLAN discovery if it is shipped in ZTP mode. VLAN discovery is supported only for the in-band management port. It is not supported for the out-of-band management ports.

After the node is installed and powered up:

1. ZTP is attempted on the null (untagged) port first, including the out-of-band management port, and then on all in-band management ports with operational links.

   • SR OS scans each port with an operational link and sends IPv4 DHCP discovery messages.

   • SR OS waits for the DHCP offer within the DHCP timeout.

2. The first VLAN with a valid offer that includes the IPv4 DHCP Options 66 and 67, or Option 67 or 43, or IPv6 DHCP Option 59 or 17 is selected as the working VLAN and the ZTP process is executed on this VLAN.

   Note: If there is no offer or the offer does not have the relevant or correct options, SR OS floods the network with DHCP discovery messages on all remaining non-reserved VLANs (1 to 4094).

3. When a VLAN is discovered, the ZTP process is executed on the respective VLAN as described in the following sections.

   Note: If there is no offer on any VLAN or the offer does not have the relevant or correct options, the node starts over from step 1.