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%C4K_HWPORTMAN-4-BLOCKEDTXQUEUE: Blocked transmit queue HwTxQId3 on Switc

Hello All

File Server has a connection on gig 1/18

interface GigabitEthernet1/18
switchport access vlan 194
switchport mode access
qos trust dscp
tx-queue 3
   priority high
no cdp enable
spanning-tree portfast

Config was like this last 2 years tonight I started to recieve these messages and people cannot reach the server

When I remove

qos trust dscp
tx-queue 3
   priority high
part seemed like everything is OK

Any idea ? should I remove these line from other ports also for other servers ?



New Member

Re: %C4K_HWPORTMAN-4-BLOCKEDTXQUEUE: Blocked transmit queue HwTx

Hi Ersin,

I tried checking the explantion of the error and the issue which can cause the error to get generated but all i can see that there are different bugs effecting different versions of switch platforms.

Please send me the show version and the show log from the switch to check the issue or you can also open up a TAC service request for the same.



New Member

Re: %C4K_HWPORTMAN-4-BLOCKEDTXQUEUE: Blocked transmit queue HwTx

I checked more and got the issue now.

Core issue    

The %C4K_HWPORTMAN-4-BLOCKEDTXQUEUE:Blocked transmit queue HwTxQId[dec]on[char], count=[dec] error message is generated on a Cisco Catalyst 4500 series switch when connected to a device. This error is a rate-limited message that indicates a transmit queue blockage on a port.

In this case, the traffic on the affected port is limited and blocked for reasons other than being paused. This blockage can occur if the supervisor is not able to send packets to the line card because a busybit message is received. In this situation, blocked transmit queue messages are seen. A bad hardware or speed and duplex mismatch can cause this problem.

Resolution      Perform these procedures as a workaround for this issue:


      Issue the shut /no shut commands to recover the port and configure both ends to operate at the same speed and duplex, as per Cisco bug ID CSCsb62330.

      If the problem persists, move the connected device to another port and see if the problem also happens there.  
   3. Issue the hw-module reset command to reboot the switch or reset the line card, as a final attempt to unblock the Transmit (Tx) queue.

Alternatively, upgrade the the Cisco IOS® version to the 12.2(25)EWA2 and 12.2(25)SG releases, which have the fix for this problem, as per Cisco bug ID CSCsb01311.

I hope that answers your concerns!


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