Long time to obtain IP addresses from S series switch

Users on S series switches except S1700 switches obtain IP addresses slowly because the STP function is enabled on interfaces of the switches. (By default, STP is enabled on all interfaces of a switch.)
When an interface of a switch goes Up, STP convergence is performed for about 30 seconds. During STP convergence, the switch discards all received packets including DHCP request packets sent from users. As a result, the users obtain IP addresses slowly.
You can resolve the problem using either of the following methods:
- Run the stp edged-port enable command to configure the switch interface connected to users as an edge interface.
If the stp bpdu-protection command has been configured on the switch, the edge interface of the switch goes Down when the switch receives attack BPDUs. To enable the edge interface to automatically go Up, run the error-down auto-recovery cause bpdu-protection interval interval-value command.
- If no physical ring topology exists on the network, you can run the stp disable command on the switch globally or on the switch interface connected to users.
Additionally, when the switch functions as a DHCP server and after you remove and reinstall the network cable, the PC obtains an IP address after 1 minute. The problem may be caused by a software bug. When you remove and reinstall the network cable, the PC sends DHCP Request messages to the DHCP server. In earlier versions of a switch, software cannot properly process this event.

Scroll to top