Errdisable Port State Recovery
Errdisable Port State Recovery on the Cisco IOS
Platforms
Document ID: 69980
Introduction
Prerequisites
Requirements
Components Used
Conventions
Background Information
Platforms That Use Errdisable
Errdisable
Function of Errdisable
Causes of Errdisable
Determine If Ports Are in the Errdisabled State
Determine the Reason for the Errdisabled State (Console Messages, Syslog, and the show
errdisable recovery Command)
Recover a Port from Errdisabled State
NetPro Discussion Forums − Featured Conversations
Related Information
Introduction
This document defines the errdisabled state, describes how to recover from it, and provides examples of
errdisable recovery. This document uses the terms errdisable and error disable interchangeably. Customers
often contact Cisco Technical Support when they notice that one or more of their switch ports have become
error disabled, which means that the ports have a status of errdisabled. These customers want to know why the
error disablement happened and how they can restore the ports to normal.
Note: The port status of err−disabled displays in the output of the show interfaces interface_number
status command.
Prerequisites
Requirements
There are no specific requirements for this document.
Components Used
In order to create the examples in this document, you need two Cisco Catalyst 4500/6500 Series Switches (or
the equivalent) in a lab environment with cleared configurations. The switches should run Cisco IOS®
Software and each switch should have two Fast Ethernet ports that are capable of EtherChannel and PortFast.
The information in this document was created from the devices in a specific lab environment. All of the
devices used in this document started with a cleared (default) configuration. If your network is live, make sure
that you understand the potential impact of any command.
Conventions
Refer to Cisco Technical Tips Conventions for more information on document conventions.
Background Information
Platforms That Use Errdisable
The errdisable feature is supported on these Catalyst switches:
• Catalyst switches that run Cisco IOS Software:
♦ 2900XL / 3500XL
♦ 2940 / 2950 / 2960 / 2970
♦ 3550 / 3560 / 3560−E / 3750 / 3750−E
♦ 4000 / 4500
♦ 6000 / 6500
• Catalyst switches that run Catalyst OS (CatOS) software:
♦ 2948G
♦ 4500 / 4000
♦ 5500 / 5000
♦ 6500 / 6000
The way in which errdisable is implemented varies between software platforms. This document specifically
focuses on errdisable for switches that run Cisco IOS Software.
Errdisable
Function of Errdisable
If the configuration shows a port to be enabled, but software on the switch detects an error situation on the
port, the software shuts down that port. In other words, the port is automatically disabled by the switch
operating system software because of an error condition that is encountered on the port.
When a port is error disabled, it is effectively shut down and no traffic is sent or received on that port. The
port LED is set to the color orange and, when you issue the show interfaces command, the port status shows
err−disabled. Here is an example of what an error−disabled port looks like from the command−line
interface (CLI) of the switch:
cat6knative#show interfaces gigabitethernet 4/1 status
Port
Gi4/1
Name
Status
Vlan
err−disabled 100
Duplex
full
Speed Type
1000 1000BaseSX
Or, if the interface has been disabled because of an error condition, you can see messages that are similar to
these in both the console and the syslog:
%SPANTREE−SP−2−BLOCK_BPDUGUARD:
Received BPDU on port GigabitEthernet4/1 with BPDU Guard enabled. Disabling port.
%PM−SP−4−ERR_DISABLE:
bpduguard error detected on Gi4/1, putting Gi4/1 in err−disable state
This example message displays when a host port receives the bridge protocol data unit (BPDU). The actual
message depends on the reason for the error condition.
The error disable function serves two purposes:
• It lets the administrator know when and where there is a port problem.
• It eliminates the possibility that this port can cause other ports on the module (or the entire module) to
fail.
Such a failure can occur when a bad port monopolizes buffers or port error messages monopolize
interprocess communications on the card, which can ultimately cause serious network issues. The
error disable feature helps prevent these situations.
Causes of Errdisable
This feature was first implemented to handle special collision situations in which the switch detected
excessive or late collisions on a port. Excessive collisions occur when a frame is dropped because the switch
encounters 16 collisions in a row. Late collisions occur after every device on the wire should have recognized
that the wire was in use. Possible causes of these types of errors include:
• A cable that is out of specification (either too long, the wrong type, or defective)
• A bad network interface card (NIC) card (with physical problems or driver problems)
• A port duplex misconfiguration
A port duplex misconfiguration is a common cause of the errors because of failures to negotiate the
speed and duplex properly between two directly connected devices (for example, a NIC that connects
to a switch). Only half−duplex connections should ever have collisions in a LAN. Because of the
carrier sense multiple access (CSMA) nature of Ethernet, collisions are normal for half duplex, as
long as the collisions do not exceed a small percentage of traffic.
There are various reasons for the interface to go into errdisable. The reason can be:
• Duplex mismatch
• Port channel misconfiguration
• BPDU guard violation
• UniDirectional Link Detection (UDLD) condition
• Late−collision detection
• Link−flap detection
• Security violation
• Port Aggregation Protocol (PAgP) flap
• Layer 2 Tunneling Protocol (L2TP) guard
• DHCP snooping rate−limit
• Incorrect GBIC / Small Form−Factor Pluggable (SFP) module or cable
• Address Resolution Protocol (ARP) inspection
• Inline power
Note: Error−disable detection is enabled for all of these reasons by default. In order to disable error−disable
detection, use the no errdisable detect cause command. The show errdisable detect command displays the
error−disable detection status.
Determine If Ports Are in the Errdisabled State
You can determine if your port has been error disabled if you issue the show interfaces command.
Here is an example of an active port:
cat6knative#show interfaces gigabitethernet 4/1 status
!−−− Refer to show interfaces status for more information on the command.
Port
Gi4/1
Name
Status
Connected
Vlan
100
Duplex
full
Speed Type
1000 1000BaseSX
Here is an example of the same port in the error disabled state:
cat6knative#show interfaces gigabitethernet 4/1 status
!−−− Refer to show interfaces status for more information on the command.
Port
Gi4/1
Name
Status
Vlan
err−disabled 100
Duplex
full
Speed Type
1000 1000BaseSX
Note: When a port is error disabled, the LED on the front panel that is associated with the port is off.
Determine the Reason for the Errdisabled State (Console Messages,
Syslog, and the show errdisable recovery Command)
When the switch puts a port in the error−disabled state, the switch sends a message to the console that
describes why it disabled the port. The example in this section provides two sample messages that show the
reason for port disablement:
• One disablement is because of the PortFast BPDU guard feature.
• The other disablement is because of an EtherChannel configuration problem.
Note: You can also see these messages in the syslog if you issue the show log command.
Here are the sample messages:
%SPANTREE−SP−2−BLOCK_BPDUGUARD:
Received BPDU on port GigabitEthernet4/1 with BPDU Guard enabled. Disabling port.
%PM−SP−4−ERR_DISABLE:
bpduguard error detected on Gi4/1, putting Gi4/1 in err−disable state
%SPANTREE−2−CHNMISCFG: STP loop − channel 11/1−2 is disabled in vlan 1
If you have enabled errdisable recovery, you can determine the reason for the errdisable status if you issue
the show errdisable recovery command. Here is an example:
cat6knative#show errdisable recovery
ErrDisable Reason
Timer Status
−−−−−−−−−−−−−−−−−
−−−−−−−−−−−−−−
udld
Enabled
bpduguard
Enabled
security−violatio
Enabled
channel−misconfig
Enabled
pagp−flap
Enabled
dtp−flap
Enabled
link−flap
Enabled
l2ptguard
Enabled
psecure−violation
Enabled
gbic−invalid
Enabled
dhcp−rate−limit
Enabled
mac−limit
Enabled
unicast−flood
arp−inspection
Enabled
Enabled
Timer interval: 300 seconds
Interfaces that will be enabled at the next timeout:
Interface
−−−−−−−−−
Fa2/4
Errdisable reason
−−−−−−−−−−−−−−−−−−−−−
bpduguard
Time left(sec)
−−−−−−−−−−−−−−
273
Recover a Port from Errdisabled State
This section provides examples of how you can encounter an error−disabled port and how to fix it, as well as
a brief discussion of a few additional reasons that a port can become error disabled. In order to recover a port
from the errdisable state, first identify and correct the root problem, and then reenable the port. If you reenable
the port before you fix the root problem, the ports just become error disabled again.
Correct the Root Problem
After you discover why the ports were disabled, fix the root problem. The fix depends on the triggering
problem. There are numerous things that can trigger the shutdown. This section discusses some of the most
noticeable and common causes:
• EtherChannel misconfiguration
In order for EtherChannel to work, the ports that are involved must have consistent configurations.
The ports must have the same VLAN, the same trunk mode, the same speed, the same duplex, and so
on. Most of the configuration differences within a switch are caught and reported when you create the
channel. If one switch is configured for EtherChannel and the other switch is not configured for
EtherChannel, the spanning tree process can shut down the channeled ports on the side that is
configured for EtherChannel. The on mode of EtherChannel does not send PAgP packets to negotiate
with the other side before channeling; it just assumes that the other side is channeling. In addition, this
example does not turn on EtherChannel for the other switch, but leaves these ports as individual,
unchanneled ports. If you leave the other switch in this state for a minute or so, Spanning Tree
Protocol (STP) on the switch where the EtherChannel is turned on thinks that there is a loop. This
puts the channeling ports in the errdisabled state.
In this example, a loop was detected and the ports were disabled. The output of the show
etherchannel summary command shows that the Number of channel−groups in use is 0.
When you look at one of the ports that are involved, you can see that the status is err−disabled:
%SPANTREE−2−CHNL_MISCFG: Detected loop due to etherchannel misconfiguration
of Gi4/1
cat6knative#show etherchannel summary
!−−− Refer to show etherchannel for more information on the command.
Flags:
D
I
H
R
U
−
−
−
−
−
down
stand−alone
Hot−standby
Layer3
in use
P − in port−channel
s − suspended
(LACP only)
S − Layer2
f − failed to allocate aggregator
u − unsuitable for bundling
Number of channel−groups in use: 0
Number of aggregators:
0
Group Port−channel Protocol
Ports
−−−−−−+−−−−−−−−−−−−−+−−−−−−−−−−−+−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−
The EtherChannel was torn down because the ports were placed in errdisable on this switch.
cat6knative#show interfaces gigabitethernet 4/1 status
Port
Gi4/1
Name
Status
Vlan
err−disabled 100
Duplex
full
Speed Type
1000 1000BaseSX
In order to determine what the problem was, look at the error message. The message indicates that the
EtherChannel encountered a spanning tree loop. As this section explains, this problem can occur when
one device (the switch, in this case) has EtherChannel turned on manually with use of the on mode (as
opposed to desirable) and the other connected device (the other switch, in this case) does not have
EtherChannel turned on at all. One way to fix the situation is to set the channel mode to desirable on
both sides of the connection, and then reenable the ports. Then, each side forms a channel only if both
sides agree to channel. If they do not agree to channel, both sides continue to function as normal
ports.
cat6knative(config−terminal)#interface gigabitethernet 4/1
cat6knative(config−if)#channel−group 3 mode desirable non−silent
• Duplex mismatch
Duplex mismatches are common because of failures to autonegotiate speed and duplex properly.
Unlike a half duplex device, which must wait until there are no other devices that transmit on the
same LAN segment, a full−duplex device transmits whenever the device has something to send,
regardless of other devices. If this transmission occurs while the half−duplex device transmits, the
half−duplex device considers this either a collision (during the slot time) or a late collision (after the
slot time). Because the full−duplex side never expects collisions, this side never realizes that it must
retransmit that dropped packet. A low percentage rate of collisions is normal with half duplex but is
not normal with full duplex. A switch port that receives many late collisions usually indicates a
duplex mismatch problem. Be sure that the ports on both sides of the cable are set to the same speed
and duplex. The show interfaces interface_number command tells you the speed and duplex for
Catalyst switch ports. Later versions of Cisco Discovery Protocol (CDP) can warn you about a duplex
mismatch before the port is put in the error−disabled state.
In addition, there are settings on a NIC, such as autopolarity features, that can cause the problem. If
you are in doubt, turn these settings off. If you have multiple NICs from a vendor and the NICs all
appear to have the same problem, check the manufacturer website for the release notes and be sure
that you have the latest drivers.
Other causes of late collisions include:
♦ A bad NIC (with physical problems, not just configuration problems)
♦ A bad cable
♦ A cable segment that is too long
• BPDU port guard
A port that uses PortFast must only connect to an end station (such as a workstation or server) and not
to devices that generate spanning tree BPDUs, such as switches, or bridges and routers that do
bridging. If the switch receives a spanning tree BPDU on a port that has spanning tree PortFast and
spanning tree BPDU guard enabled, the switch puts the port in errdisabled mode in order to guard
against potential loops. PortFast assumes that a port on a switch cannot generate a physical loop.
Therefore, PortFast skips the initial spanning tree checks for that port, which avoids the timeout of
end stations at bootup. The network administrator must carefully implement PortFast. On ports that
have PortFast enabled, BPDU guard helps ensure that the LAN stays loop−free.
This example shows how to turn on this feature. This example was chosen because creation of an
error−disable situation is easy in this case:
cat6knative(config−if)#spanning−tree bpduguard enable
!−−− Refer to spanning−tree bpduguard for more information on the command.
In this example, a Catalyst 6509 switch is connected to another switch (a 6509). The 6500 sends
BPDUs every 2 seconds (with use of the default spanning tree settings). When you enable PortFast on
the 6509 switch port, the BPDU guard feature watches for BPDUs that come in on this port. When a
BPDU comes into the port, which means that a device that is not an end device is detected on that
port, the BPDU guard feature error disables the port in order to avoid the possibility of a spanning tree
loop.
cat6knative(config−if)#spanning−tree portfast enable
!−−− Refer to spanning−tree portfast (interface configuration mode)
!−−− for more information on the command.
Warning: Spantree port fast start should only be enabled on ports connected
to a single host. Connecting hubs, concentrators, switches, bridges, etc. to
a fast start port can cause temporary spanning tree loops.
%PM−SP−4−ERR_DISABLE: bpduguard error detected on Gi4/1, putting Gi4/1 in
err−disable state.
In this message, the switch indicates that it received a BPDU on a PortFast−enabled port, and so the
switch shuts down port Gi4/1.
cat6knative#show interfaces gigabitethernet 4/1 status
Port
Gi4/1
Name
Status
Vlan
err−disabled 100
Duplex
full
Speed Type
1000 1000BaseSX
You need to turn off the PortFast feature because this port is a port with an improper connection. The
connection is improper because PortFast is enabled, and the switch connects to another switch.
Remember that PortFast is only for use on ports that connect to end stations.
cat6knative(config−if)#spanning−tree portfast disable
• UDLD
The UDLD protocol allows devices that are connected through fiber−optic or copper Ethernet cables
(for example, Category 5 cabling) to monitor the physical configuration of the cables and detect when
a unidirectional link exists. When a unidirectional link is detected, UDLD shuts down the affected
port and alerts the user. Unidirectional links can cause a variety of problems, which include
spanning−tree topology loops.
Note: UDLD works by exchanging protocol packets between the neighboring devices. Both devices
on the link must support UDLD and have UDLD enabled on the respective ports. If you have UDLD
enabled on only one port of a link, it can also leave the end configured with UDLD to go to errdisable
state.
Each switch port that is configured for UDLD sends UDLD protocol packets that contain the port
device (or port ID) and the neighbor device (or port IDs) that are seen by UDLD on that port. The
neighboring ports must see their own device or port ID (echo) in the packets that are received from
the other side. If the port does not see its own device or port ID in the incoming UDLD packets for a
specific duration of time, the link is considered unidirectional. Therefore, the respective port is
disabled and a message that is similar to this is printed on the console:
PM−SP−4−ERR_DISABLE: udld error detected on Gi4/1, putting Gi4/1 in
err−disable state.
For more information on UDLD operation, configuration, and commands, refer to the document
Configuring UniDirectional Link Detection (UDLD).
• Link−flap error
Link flap means that the interface continually goes up and down. The interface is put into the
errdisabled state if it flaps more than five times in 10 seconds. The common cause of link flap is a
Layer 1 issue such as a bad cable, duplex mismatch, or bad Gigabit Interface Converter (GBIC) card.
Look at the console messages or the messages that were sent to the syslog server that state the reason
for the port shutdown.
%PM−4−ERR_DISABLE: link−flap error detected on Gi4/1, putting Gi4/
1 in err−disable state
Issue this command in order to view the flap values:
cat6knative#show errdisable flap−values
!−−− Refer to show errdisable flap−values for more information on the command.
ErrDisable Reason
−−−−−−−−−−−−−−−−−
pagp−flap
dtp−flap
link−flap
Flaps
−−−−−−
3
3
5
Time (sec)
−−−−−−−−−−
30
30
10
• Loopback error
A loopback error occurs when the keepalive packet is looped back to the port that sent the keepalive.
The switch sends keepalives out all the interfaces by default. A device can loop the packets back to
the source interface, which usually occurs because there is a logical loop in the network that the
spanning tree has not blocked. The source interface receives the keepalive packet that it sent out, and
the switch disables the interface (errdisable). This message occurs because the keepalive packet is
looped back to the port that sent the keepalive:
%PM−4−ERR_DISABLE: loopback error detected on Gi4/1, putting Gi4/1 in
err−disable state
Keepalives are sent on all interfaces by default in Cisco IOS Software Release 12.1EA−based
software. In Cisco IOS Software Release 12.2SE−based software and later, keepalives are not sent by
default on fiber and uplink interfaces. For more information, refer to Cisco bug ID CSCea46385 (
registered customers only) .
The suggested workaround is to disable keepalives and upgrade to Cisco IOS Software Release
12.2SE or later.
• Port security violation
You can use port security with dynamically learned and static MAC addresses in order to restrict the
ingress traffic of a port. In order to restrict the traffic, you can limit the MAC addresses that are
allowed to send traffic into the port. In order to configure the switch port to error disable if there is a
security violation, issue this command:
cat6knative(config−if)#switchport port−security violation shutdown
A security violation occurs in either of these two situations:
♦ When the maximum number of secure MAC addresses is reached on a secure port and the
source MAC address of the ingress traffic differs from any of the identified secure MAC
addresses
In this case, port security applies the configured violation mode.
♦ If traffic with a secure MAC address that is configured or learned on one secure port attempts
to access another secure port in the same VLAN
In this case, port security applies the shutdown violation mode.
For more information on port security, refer to Configuring Port Security.
• L2pt guard
When the Layer 2 PDUs enter the tunnel or access port on the inbound edge switch, the switch
overwrites the customer PDU−destination MAC address with a well−known Cisco proprietary
multicast address (01−00−0c−cd−cd−d0). If 802.1Q tunneling is enabled, packets are also
double−tagged. The outer tag is the customer metro tag and the inner tag is the customer VLAN tag.
The core switches ignore the inner tags and forward the packet to all trunk ports in the same metro
VLAN. The edge switches on the outbound side restore the proper Layer 2 protocol and MAC address
information and forward the packets to all tunnel or access ports in the same metro VLAN. Therefore,
the Layer 2 PDUs are kept intact and delivered across the service−provider infrastructure to the other
side of the customer network.
Switch(config)#interface gigabitethernet 0/7
l2protocol−tunnel {cdp | vtp | stp}
The interface goes to errdisabled state. If an encapsulated PDU (with the proprietary destination MAC
address) is received from a tunnel port or access port with Layer 2 tunneling enabled, the tunnel port
is shut down to prevent loops. The port also shuts down when a configured shutdown threshold for the
protocol is reached. You can manually reenable the port (by issuing a shutdown, no shutdown
command sequence) or if errdisable recovery is enabled, the operation is retried after a specified time
interval.
The interface can be recovered from errdisable state by reenabling the port using the command
errdisable recovery cause l2ptguard. This command is used to configure the recovery mechanism
from a Layer 2 maximum rate error so that the interface can be brought out of the disabled state and
allowed to try again. You can also set the time interval. Errdisable recovery is disabled by default;
when enabled, the default time interval is 300 seconds.
• Incorrect SFP cable
Ports go into errdisable state with the %PHY−4−SFP_NOT_SUPPORTED error message when you
connect Catalyst 3560 and Catalyst 3750 Switches using an SFP Interconnect Cable.
The Cisco Catalyst 3560 SFP Interconnect Cable (CAB−SFP−50CM=) provides for a low−cost,
point−to−point, Gigabit Ethernet connection between Catalyst 3560 Series Switches. The
50−centimeter (cm) cable is an alternative to using SFP transceivers when interconnecting Catalyst
3560 Series Switches through their SFP ports over a short distance. All Cisco Catalyst 3560 Series
Switches support the SFP Interconnect Cable.
When a Catalyst 3560 Switch is connected to a Catalyst 3750 or any other type of Catalyst switch
model, you cannot use the CAB−SFP−50CM= cable. You can connect both switches using a copper
cable with SFP (GLC−T) on both devices instead of a CAB−SFP−50CM= cable.
Reenable the Errdisabled Ports
After you fix the root problem, the ports are still disabled if you have not configured errdisable recovery on
the switch. In this case, you must reenable the ports manually. Issue the shutdown command and then the no
shutdown interface mode command on the associated interface in order to manually reenable the ports.
The errdisable recovery command allows you to choose the type of errors that automatically reenable the
ports after a specified amount of time. The show errdisable recovery command shows the default
error−disable recovery state for all the possible conditions.
cat6knative#show errdisable recovery
ErrDisable Reason
Timer Status
−−−−−−−−−−−−−−−−−
−−−−−−−−−−−−−−
udld
Disabled
bpduguard
Disabled
security−violatio
Disabled
channel−misconfig
Disabled
pagp−flap
Disabled
dtp−flap
Disabled
link−flap
Disabled
l2ptguard
Disabled
psecure−violation
Disabled
gbic−invalid
Disabled
dhcp−rate−limit
Disabled
mac−limit
Disabled
unicast−flood
Disabled
arp−inspection
Disabled
Timer interval: 300 seconds
Interfaces that will be enabled at the next timeout:
Note: The default timeout interval is 300 seconds and, by default, the timeout feature is disabled.
In order to turn on errdisable recovery and choose the errdisable conditions, issue this command:
cat6knative#errdisable recovery cause
all
Enable timer to
arp−inspection
Enable timer to
state
bpduguard
Enable timer to
state
channel−misconfig
Enable timer to
state
dhcp−rate−limit
Enable timer to
disable state
dtp−flap
Enable timer to
gbic−invalid
Enable timer to
state
l2ptguard
Enable timer to
disable state
link−flap
Enable timer to
state
mac−limit
Enable timer to
pagp−flap
Enable timer to
state
psecure−violation
Enable timer to
state
security−violation Enable timer to
state
udld
Enable timer to
unicast−flood
Enable timer to
?
recover from all causes
recover from arp inspection error disable
recover from BPDU Guard error disable
recover from channel misconfig disable
recover from dhcp−rate−limit error
recover from dtp−flap error disable state
recover from invalid GBIC error disable
recover from l2protocol−tunnel error
recover from link−flap error disable
recover from mac limit disable state
recover from pagp−flap error disable
recover from psecure violation disable
recover from 802.1x violation disable
recover from udld error disable state
recover from unicast flood disable state
This example shows how to enable the BPDU guard errdisable recovery condition:
cat6knative(Config)#errdisable recovery cause bpduguard
A nice feature of this command is that, if you enable errdisable recovery, the command lists general reasons
that the ports have been put into the error−disable state. In this example, notice that the BPDU guard feature
was the reason for the shutdown of port 2/4:
cat6knative#show errdisable recovery
ErrDisable Reason
Timer Status
−−−−−−−−−−−−−−−−−
−−−−−−−−−−−−−−
udld
Disabled
bpduguard
Enabled
security−violatio
Disabled
channel−misconfig
Disabled
pagp−flap
Disabled
dtp−flap
Disabled
link−flap
Disabled
l2ptguard
Disabled
psecure−violation
Disabled
gbic−invalid
Disabled
dhcp−rate−limit
Disabled
mac−limit
Disabled
unicast−flood
Disabled
arp−inspection
Disabled
Timer interval: 300 seconds
Interfaces that will be enabled at the next timeout:
Interface
−−−−−−−−−
Fa2/4
Errdisable reason
−−−−−−−−−−−−−−−−−−−−−
bpduguard
Time left(sec)
−−−−−−−−−−−−−−
290
If any one of the errdisable recovery conditions is enabled, the ports with this condition are reenabled after
300 seconds. You can also change this default of 300 seconds if you issue this command:
cat6knative(Config)#errdisable recovery interval timer_interval_in_seconds
This example changes the errdisable recovery interval from 300 to 400 seconds:
cat6knative(Config)#errdisable recovery interval 400
Verify
• show versionDisplays the version of the software that is used on the switch.
• show interfaces interface interface_number statusShows the current status of the switch port.
• show errdisable detectDisplays the current settings of the errdisable timeout feature and, if any of
the ports are currently error disabled, the reason that they are error disabled.
Troubleshoot
• show interfaces status err−disabledShows which local ports are involved in the errdisabled state.
• show etherchannel summaryShows the current status of the EtherChannel.
• show errdisable recoveryShows the time period after which the interfaces are enabled for
errdisable conditions.
• show errdisable detectShows the reason for the errdisable status.
For more information on troubleshooting switchport issues, refer to Troubleshooting Switch Port and
Interface Problems.
NetPro Discussion Forums − Featured Conversations
Networking Professionals Connection is a forum for networking professionals to share questions, suggestions,
and information about networking solutions, products, and technologies. The featured links are some of the
most recent conversations available in this technology.
NetPro Discussion Forums − Featured Conversations for LAN
Network Infrastructure: LAN Routing and Switching
Network Infrastructure: Getting Started with LANs
Related Information
• Recovering From errDisable Port State on the CatOS Platforms
• Interface Is in errdisable Status section of Troubleshooting Hardware and Common Issues on
Catalyst 6500/6000 Series Switches Running Cisco IOS System Software
• Spanning Tree PortFast BPDU Guard Enhancement
• Understanding EtherChannel Inconsistency Detection
• Troubleshooting Switch Port and Interface Problems
• LAN Product Support
• LAN Switching Technology Support
• Technical Support & Documentation − Cisco Systems
All contents are Copyright © 2006−2007 Cisco Systems, Inc. All rights reserved. Important Notices and Privacy Statement.
Updated: Jul 05, 2007
Document ID: 69980
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement