Allen-Bradley armorstratix 5700, Руководство пользователя, Страница: 111 / 458

Rockwell Automation Publication 1783-UM007I-EN-P - December 2017 111
Configure Switch Features Chapter 3
DHCP for Ring Devices
Stratix 5400, Stratix 5700, and ArmorStratix 5700 switches that support DLR
also support DHCP for ring devices.
You can configure DHCP to assign IP addresses to devices connected to a ring
based on their positions in the ring. This feature makes sure that a replaced
device receives the expected IP address:
•
A ring supervisor functions as the active ring DHCP server to assign IP
addresses to the participating nodes through two DLR ports.
•
If enabled, a backup ring DHCP server runs on the backup ring
supervisor and obtains its reference table automatically from the active
ring DHCP server on the active ring supervisor. There can be multiple
backup ring DHCP servers in the ring.
•
If the active ring DHCP server in the ring fails, the backup ring
supervisor becomes the active supervisor. The backup ring DHCP
server on the backup ring supervisor becomes the active ring DHCP
server and takes over IP assignment and renewal for the ring until one of
the following happens:
–
The original active ring DHCP server is restored.
–
A new active ring DHCP server is manually configured.
Figure 15 - DHCP Snooping Checkboxes
IMPORTANT DHCP for ring devices does not work with DHCP peristence as described on
page 131 . Configure only one of these features on your switch.
IMPORTANT To enable a ring to assign correct addresses by using DHCP, you must check
both DHCP Snooping checkboxes on the DHCP page, as shown in Figure 15 .