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The MBUF freezes the WLC during heavy DHCP traffic with the sysapi_if_net.c 201: MbufGet: no free Mbufs error message

Core Issue

After running the WLC for an extensive period of time with controller traffic going on the MBUF(controller network packet buffer) runs out and the system stops functioning and freezes.


This problem is documented in Cisco bug ID CSCsb93817.

It happens when there are numerous Dynamic Host Control Protocol (DHCP) activities going through the WLC.

There is no workaround for this issue. This problem has been fixed in WLC version  3.2(78).

To download the latest version, go to Software Download: 4100 Series WLC.

Problem Type

Poor connectivity / Performance

Error message


Wireless LAN Controllers


LWAPP network

IP Address Assignment

Dynamic addressing (DHCP)

Wireless Devices Errors, Warnings, Statistics and Log Messages

sysapi_if_net.c 201: MbufGet: no free Mbufs

SW Features

Lightwieght Access Point Protocol (LWAPP)

Version history
Revision #:
1 of 1
Last update:
‎06-22-2009 05:37 PM
Updated by: