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All the switches in the stack must be running the same license level as the active switch. For information about license levels, see the System Management section of this guide.
All the switches in the switch stack must be running compatible software versions.
The following are restrictions for your switch stack configuration:
Only homogenous stacking is supported, that is, a stack of Cisco Catalyst 9300 Series Switches stack with only Cisco Catalyst 9300 Series Switches as stack members.
Cisco Catalyst 9300L Series Switches stack with only Cisco Catalyst 9300L Series Switches as stack members.
C9300-24UB, C9300-24UXB, and C9300-48UB switches can only be stacked with each other.
During a switchover, when the standby device syncs with the active device, the following log message is displayed on the console:
%SM-4-BADEVENT: Event 'standby_phy_link_up' is invalid for
the current state 'NO_NEIGHBOR': rep_lsl_rx Gix/x/x -Traceback=Ignore this message. It does not have any functional or operational impact.
You cannot have a switch stack containing a mix of different license levels.
A switch stack can have up to eight stacking-capable switches connected through their StackWise-480 ports. Note that Cisco Catalyst 9300L series switches connect through their StackWise-320 ports.The stack members work together as a unified system. Layer 2 and Layer 3 protocols present the entire switch stack as a single entity to the network.
A switch stack always has one active switch and one standby switch. If the active switch becomes unavailable, the standby switch assumes the role of the active switch, and continues to the keep the stack operational.
The active switch controls the operation of the switch stack, and is the single point of stack-wide management.
From the active switch, you configure:
System-level (global) features that apply to all stack members
Interface-level features for each stack member
The active switch contains the saved and running configuration files for the switch stack. The configuration files include the system-level settings for the switch stack and the interface-level settings for each stack member. Each stack member has a current copy of these files for back-up purposes.
A standalone is a stack with one stack member that also operates as the active switch. You can connect one standalone to another to create a stack containing two stack members, with one of them as the active switch. You can connect standalone to an existing stack to increase the stack membership.
If a stack member does not respond, that member is removed from the stack.
If the standby does not respond, a new standby is elected.
If the active does not respond, the standby becomes the active .
If the standby does not respond, a new standby is elected.
If the active does not respond, the standby becomes the active .
If you replace a stack member with an identical model, the new switch functions with exactly the same configuration as the replaced switch, assuming that the new switch (referred to as the provisioned switch) is using the same member number as the replaced switch.
The operation of the switch stack continues uninterrupted during membership changes unless you remove the active switch or you add powered-on standalone switches or switch stacks.
Adding powered-on switches (merging) causes all switches to reload and elect a new active switch from among themselves. The newly elected active switch retains its role and configuration. All other switches retain their stack member numbers and use the stack configuration of the newly elected active switch.
Removing powered-on stack members causes the switch stack to divide (partition) into two or more switch stacks, each with the same configuration. This can cause:
An IP address conflict in your network. If you want the switch stacks to remain separate, change the IP address or addresses of the newly created switch stacks.
A MAC address conflict between two members in the stack. You can use the stack-mac update force command to resolve the conflict.
If a newly created switch stack does not have an active switch or standby switch, the switch stack will reload and elect a new active switch.
 Note |
Make sure that you power off the switches that you add to or remove from the switch stack. After adding or removing stack members, make sure that the switch stack is operating at full bandwidth. Press the Mode button on a stack member until the Stack mode LED is on. The last two right port LEDs on all switches in the stack should be green. Depending on the switch model, the last two right ports are 10-Gigabit Ethernet ports or small form-factor pluggable (SFP) module ports (10/100/1000 ports). If one or both of these LEDs are not green on any of the switches, the stack is not operating at full bandwidth. |
If you remove powered-on members but do not want to partition the stack:
Power off the switches in the newly created switch stacks.
Reconnect them to the original switch stack through their stack ports.
Power on the switches.
For cabling and power considerations that affect switch stacks, see the Cisco Catalyst 9300 Series Switches Hardware Installation Guide .
The stack member number (1 to 8) identifies each member in the switch stack. The member number also determines the interface-level configuration that a stack member uses. You can display the stack member number by using the show switch EXEC command.
A new, out-of-the-box switch (one that has not joined a switch stack or has not been manually assigned a stack member number) ships with a default stack member number of 1. When it joins a switch stack, its default stack member number changes to the lowest available member number in the stack.
Stack members in the same switch stack cannot have the same stack member number. Every stack member, including a standalone switch, retains its member number until you manually change the number or unless the number is already being used by another member in the stack.
If you manually change the stack member number by using the switch current-stack-member-number renumber new-stack-member-number EXEC command, the new number goes into effect after that stack member resets (or after you use the reload slot stack-member-number privileged EXEC command) and only if that number is not already assigned to any other members in the stack. Another way to change the stack member number is by changing the SWITCH_NUMBER environment variable.
If the number is being used by another member in the stack, the switch selects the lowest available number in the stack.
If you manually change the number of a stack member and no interface-level configuration is associated with that new member number, that stack member resets to its default configuration.
You cannot use the switch current-stack-member-number renumber new-stack-member-number EXEC command on a provisioned switch. If you do, the command is rejected.
If you move a stack member to a different switch stack, the stack member retains its number only if the number is not being used by another member in the stack. If it is being used, the switch selects the lowest available number in the stack.
If you merge switch stacks, the switch that join the switch stack of a new active switch select the lowest available numbers in the stack.
As described in the hardware installation guide, you can use the switch port LEDs in Stack mode to visually determine the stack member number of each stack member.
You can enter the Stack mode on any of these switches by pressing the mode button. Based on the switch number configured on each switch, the corresponding port LED will be blinking green. For instance, if the switch number configured on a particular switch is three, then the port LED-3 will be blinking green when the mode button is set to stack.
A higher priority value for a stack member increases the probability of it being elected active switch and retaining its stack member number. The priority value can be 1 to 15. The default priority value is 1. You can display the stack member priority value by using the show switch EXEC command.
Note |
We recommend assigning the highest priority value to the that you prefer to be the active switch. This ensures that the is reelected as the active switch if a reelection occurs. |
To change the priority value for a stack member, use the switch stack-member-number priority new priority-value EXEC command. For more information, see the “Setting the Stack Member Priority Value” section.
The new priority value takes effect immediately but does not affect the current active switch. The new priority value helps determine which stack member is elected as the new active switch when the current active switch or the switch stack resets.
A switch stack is identified in the network by its bridge ID and, if it is operating as a Layer 3 device, its router MAC address. The bridge ID and router MAC address are determined by the MAC address of the active switch.
If the active switch changes, the MAC address of the new active switch determines the new bridge ID and router MAC address.
If the entire switch stack reloads, the switch stack uses the MAC address of the active switch.
You can use the persistent MAC address feature to set a time delay before the stack MAC address changes. During this time period, if the previous active switch rejoins the stack, the stack continues to use its MAC address as the stack MAC address, even if the switch is now a stack member and not an active switch. If the previous active switch does not rejoin the stack during this period, the switch stack takes the MAC address of the new active switch as the stack MAC address. By default, the stack MAC address will be the MAC address of the first active switch, even if a new active switch takes over.
Note |
You can also configure stack MAC persistency so that the stack MAC address never changes to the new active switch MAC address, by using the stack-mac persistent timer 0 command. |
All stack members are eligible to be the active switch or the standby switch. If the active switch becomes unavailable, the standby switch becomes the active switch.
An active switch retains its role unless one of these events occurs:
The switch stack is reset.
The active switch is removed from the switch stack.
The active switch is reset or powered off.
The active switch fails.
The switch stack membership is increased by adding powered-on standalone switches or switch stacks.
The active switch is elected or reelected based on one of these factors and in the order listed:
The switch that is currently the active switch.
The switch with the highest stack member priority value.
Note |
We recommend assigning the highest priority value to the switch that you prefer to be the active switch. This ensures that the switch is reelected as active switch if a reelection occurs. |
The switch with the shortest start-up time.
The switch with the lowest MAC address.
Note |
The factors for electing or reelecting a new standby switch are same as those for the active switch election or reelection, and are applied to all participating switches except the active switch. |
After election, the new active switch becomes available after a few seconds. In the meantime, the switch stack uses the forwarding tables in memory to minimize network disruption. The physical interfaces on the other available stack members are not affected during a new active switch election and reset.
When the previous active switch becomes available, it does not resume its role as the active switch.
If you power on or reset an entire switch stack, some stack members might not participate in the active switch election. Stack members that are powered on within the same 2-minute timeframe participate in the active switch election and have a chance to become the active switch. Stack members that are powered on after the 120-second timeframe do not participate in this initial election and become stack members. For powering considerations that affect active-switch elections, see the switch hardware installation guide.
As described in the hardware installation guide, you can use the ACTV LED on the switch to see if the switch is the active switch.
The active switch has the saved and running configuration file for the switch stack. The standby switch automatically receives the synchronized running configuration file. Stack members receive synchronized copies when the running configuration file is saved into the startup configuration file. If the active switch becomes unavailable, the standby switch takes over with the current running configuration.
The configuration files record these settings:
System-level (global) configuration settings such as IP, STP, VLAN, and SNMP settings that apply to all stack members
Stack member interface-specific configuration settings that are specific for each stack member
Note |
The interface-specific settings of the active switch are saved if the active switch is replaced without saving the running configuration to the startup configuration. |
A new, out-of-box switch joining a switch stack uses the system-level settings of that switch stack. If a switch is moved to a different switch stack before it is powered on, that switch loses its saved configuration file and uses the system-level configuration of the new switch stack. If the switch is powered on as a standalone switch before it joins the new switch stack, the stack will reload. When the stack reloads, the new switch may become the active switch, retain its configuration and overwrite the configuration files of the other stack members.
The interface-specific configuration of each stack member is associated with the stack member number. Stack members retain their numbers unless they are manually changed or they are already used by another member in the same switch stack. If the stack member number changes, the new number goes into effect after that stack member resets.
If an interface-specific configuration does not exist for that member number, the stack member uses its default interface-specific configuration.
If an interface-specific configuration exists for that member number, the stack member uses the interface-specific configuration associated with that member number.
If you replace a failed member with an identical model, the replacement member automatically uses the same interface-specific configuration as the failed switch. You do not need to reconfigure the interface settings. The replacement switch (referred to as the provisioned switch) must have the same stack member number as the failed switch.
You back up and restore the stack configuration in the same way as you would for a standalone switch configuration.
You can use the offline configuration feature to provision (to supply a configuration to) a new switch before it joins the switch stack. You can configure the stack member number, the switch type, and the interfaces associated with a switch that is not currently part of the stack. The configuration that you create on the switch stack is called the provisioned configuration. The switch that is added to the switch stack and that receives this configuration is called the provisioned switch.
You manually create the provisioned configuration through the switch stack-member-number provision type global configuration command. You must change the stack-member-number on the provisioned switch before you add it to the stack, and it must match the stack member number that you created for the new switch on the switch stack. The switch type in the provisioned configuration must match the switch type of the newly added switch. The provisioned configuration is automatically created when a switch is added to a switch stack and when no provisioned configuration exists.
When you configure the interfaces associated with a provisioned switch, the switch stack accepts the configuration, and the information appears in the running configuration. However, as the switch is not active, any configuration on the interface is not operational and the interface associated with the provisioned switch does not appear in the display of the specific feature. For example, VLAN configuration information associated with a provisioned switch does not appear in the show vlan user EXEC command output on the switch stack.
The switch stack retains the provisioned configuration in the running configuration whether or not the provisioned switch is part of the stack. You can save the provisioned configuration to the startup configuration file by entering the copy running-config startup-config privileged EXEC command. The startup configuration file ensures that the switch stack can reload and can use the saved information whether or not the provisioned switch is part of the switch stack.
The auto-upgrade and auto-advise features enable a switch with software packages that are incompatible with the switch stack to be upgraded to a compatible software version so that it can join the switch stack.
You manage the switch stack and the stack member interfaces through the active switch. You can use the CLI, SNMP, and any of the supported network management applications. You cannot manage stack members on an individual basis.
Note |
Use SNMP to manage network features across the stack that are defined by supported MIBs. The switch does not support MIBs to manage stacking-specific features such as stack membership and election. |
If a stack port is flapping and causing instability in the stack ring, to disable the port, enter the switch stack-member-number stack port port-number disable privileged EXEC command. To reenable the port, enter the switch stack-member-number stack port port-number enable command.
Note |
Be careful when using the switch stack-member-number stack port port-number disable command. When you disable the stack port, the stack operates at half bandwidth. |
A stack is in the full-ring state when all members are connected through the stack ports and are in the ready state.
The stack is in the partial-ring state when the following occurs:
All members are connected through their stack ports but some are not in the ready state.
Some members are not connected through the stack ports.
| Command or Action | Purpose | |
|---|---|---|
| Step 1 |
switch stack-member-number stack port port-number disable Example: |
Disables the specified stack port. |
| Step 2 |
switch stack-member-number stack port port-number enable Example: |
Reenables the stack port. |
When you disable a stack port and the stack is in the full-ring state, you can disable only one stack port. This message appears:
Enabling/disabling a stack port may cause undesired stack changes. Continue?[confirm]
When you disable a stack port and the stack is in the partial-ring state, you cannot disable the port. This message appears:
Disabling stack port not allowed with current stack configuration.Stack Port 1 on Switch 1 is connected to Port 2 on Switch 4. If Port 1 is flapping, you can disable Port 1 with the switch 1 stack port 1 disable privileged EXEC command. While Port 1 on Switch 1 is disabled and Switch 1 is still powered on, follow these steps to reenable a stack port:
| Step 1 |
Disconnect the stack cable between Port 1 on Switch 1 and Port 2 on Switch 4. |
| Step 2 |
Remove Switch 4 from the stack. |
| Step 3 |
Add a switch to replace Switch 4 and assign it switch-number 4. |
| Step 4 |
Reconnect the cable between Port 1 on Switch 1 and Port 2 on Switch 4 (the replacement switch). |
| Step 5 |
Reenable the link between the switches. Enter the switch 1 stack port 1 enable privileged EXEC command to enable Port 1 on Switch 1. |
| Step 6 |
Power on Switch 4. |
 Caution |
Powering on Switch 4 before enabling the Port 1 on Switch 1 might cause one of the switches to reload. If Switch 4 is powered on first, you might need to enter the switch 1 stack port 1 enable and the switch 4 stack port 2 enable privileged EXEC commands to bring up the link. |
|
Command |
Description |
|---|---|
|
show switch |
Displays summary information about the stack, including the status of provisioned switches and switches in version-mismatch mode. |
|
show switch stack-member-number |
Displays information about a specific member. |
|
show module |
Displays summary informaton about the stack. |
|
show switch detail |
Displays detailed information about the stack. |
|
show switch neighbors |
Displays the stack neighbors. |
|
show switch stack-ports [summary ] |
Displays port information for the stack. Use the summary keyword to display the stack cable length, the stack link status, and the loopback status. |
|
show switch stack-ports [detail] |
Displays the stack link status and information for each stack member. Use the detail keyword to display the stack interface status, errors, drops, packet transmission and bandwidth details. |
|
show redundancy |
Displays the redundant system and the current processor information. The redundant system information includes the system uptime, standby failures, switchover reason, hardware, configured and operating redundancy mode. The current processor information displayed includes the active location, the software state, the uptime in the current state and so on. |
|
show redundancy state |
Displays all the redundancy states of the active and standby devices. |
Most of these switch stack configuration scenarios assume that at least two devices are connected through their StackWise ports.
|
Scenario |
Result |
|
|---|---|---|
|
Active switch election specifically determined by existing active switches |
Connect two powered-on switch stacks through the StackWise ports. |
Only one of the two active switches becomes the new active switch. |
|
Active switch election specifically determined by the stack member priority value |
|
The stack member with the higher priority value is elected active switch. |
|
Active switch election specifically determined by the configuration file |
Assuming that both member switches have the same priority value:
|
The stack member with the saved configuration file is elected active switch. |
|
Active switch election specifically determined by the MAC address |
Assuming that both member switches have the same priority value, configuration file, and license level, restart both member switches at the same time. |
The stack member with the lower MAC address is elected active switch . |
|
Stack member number conflict |
Assuming that one stack member has a higher priority value than the other stack member:
|
The stack member with the higher priority value retains its stack member number. The other stack member has a new stack member number. |
|
Add a stack member |
|
The active switch is retained. The new switch is added to the switch stack. |
|
Active switch failure |
Remove (or power off) the active switch. |
The standby switch becomes the new active switch. All other member switches in the stack remain as member switches and do not reboot. |
|
Add eight member switches |
|
Two devices become active switches. One active switch has eight member switches. The other active switch remains as a standalone device. Use the Mode button and port LEDs on the device to identify which devices are active switches and which devices belong to each active switch. |
This example shows how to configure the persistent MAC address feature for a 7-minute time delay and to verify the configuration:
(config)# stack-mac persistent timer 7
WARNING: The stack continues to use the base MAC of the old Master
WARNING: as the stack MAC after a master switchover until the MAC
WARNING: persistency timer expires. During this time the Network
WARNING: Administrators must make sure that the old stack-mac does
WARNING: not appear elsewhere in this network domain. If it does,
WARNING: user traffic may be blackholed.
(config)# end
# show switch
Switch/Stack Mac Address : 0016.4727.a900
Mac persistency wait time: 7 mins
H/W Current
Switch# Role Mac Address Priority Version State
----------------------------------------------------------
*1 0016.4727.a900 1 P2B Ready
The show running-config command output shows the interfaces associated with the provisioned switch:
(config)# switch 2 provision switch_PID
(config)# end
# show running-config | include switch 2
!
interface GigabitEthernet2/0/1
!
interface GigabitEthernet2/0/2
!
interface GigabitEthernet2/0/3
<output truncated>
Only Port 1 on stack member 2 is disabled.
# show switch stack-ports summary
#/ Stack Neighbor Cable Link Link Sync # In
Port# Port Length OK Active OK Changes Loopback
Status To LinkOK
-------- ------ -------- -------- ---- ------ ---- --------- --------
1/1 OK 3 50 cm Yes Yes Yes 1 No
1/2 Down None 3 m Yes No Yes 1 No
2/1 Down None 3 m Yes No Yes 1 No
2/2 OK 3 50 cm Yes Yes Yes 1 No
3/1 OK 2 50 cm Yes Yes Yes 1 No
3/2 OK 1 50 cm Yes Yes Yes 1 No
|
Field |
Description |
|---|---|
|
Switch#/Port# |
Member number and its stack port number. |
|
Stack Port Status |
Status of the stack port.
|
|
Neighbor |
Switch number of the active member at the other end of the stack cable. |
|
Cable Length |
Valid lengths are 50 cm, 1 m, or 3 m. If the switch cannot detect the cable length, the value is no cable. The cable might not be connected, or the link might be unreliable. |
|
Link OK |
Whether the stack cable is connected and functional. There may or may not be a neighbor connected on the other end. The link partner is a stack port on a neighbor switch.
|
|
Link Active |
Whether a neighbor is connected on the other end of the stack cable.
|
|
Sync OK |
Whether the link partner sends valid protocol messages to the stack port.
|
|
# Changes to LinkOK |
The relative stability of the link. If a large number of changes occur in a short period of time, link flapping can occur. |
|
In Loopback |
Whether a stack cable is attached to a stack port on the member.
|
The following is a sample output of the command for a working stack:
Device# show switch stack-ports detail
1/1 is DOWN Loopback No
Cable Length 50cm Neighbor NONE
Link Ok Yes Sync Ok Yes Link Active No
Changes to LinkOK 1
Five minute input rate 0 bytes/sec
Five minute output rate 0 bytes/sec
752 bytes input
240 bytes output
CRC Errors
Data CRC 0
Ringword CRC 0
InvRingWord 0
PcsCodeWord 667
1/2 is OK Loopback No
Cable Length 50cm Neighbor 3
Link Ok Yes Sync Ok Yes Link Active Yes
Changes to LinkOK 1
Five minute input rate 7 bytes/sec
Five minute output rate 0 bytes/sec
54332 bytes input
1120 bytes output
CRC Errors
Data CRC 0
Ringword CRC 0
InvRingWord 0
PcsCodeWord 0
2/1 is OK Loopback No
Cable Length 50cm Neighbor 3
Link Ok Yes Sync Ok Yes Link Active Yes
Changes to LinkOK 1
Five minute input rate 0 bytes/sec
Five minute output rate 30 bytes/sec
146390 bytes input
217587 bytes output
CRC Errors
Data CRC 0
Ringword CRC 0
InvRingWord 0
PcsCodeWord 0
2/2 is DOWN Loopback No
Cable Length 50cm Neighbor NONE
Link Ok Yes Sync Ok Yes Link Active No
Changes to LinkOK 1
Five minute input rate 0 bytes/sec
Five minute output rate 0 bytes/sec
1208 bytes input
480 bytes output
CRC Errors
Data CRC 0
Ringword CRC 0
InvRingWord 0
PcsCodeWord 0
3/1 is OK Loopback No
Cable Length 50cm Neighbor 1
Link Ok Yes Sync Ok Yes Link Active Yes
Changes to LinkOK 1
Five minute input rate 0 bytes/sec
Five minute output rate 0 bytes/sec
41245 bytes input
240 bytes output
CRC Errors
Data CRC 0
Ringword CRC 0
InvRingWord 0
PcsCodeWord 0
3/2 is OK Loopback No
Cable Length 50cm Neighbor 2
Link Ok Yes Sync Ok Yes Link Active Yes
Changes to LinkOK 1
Five minute input rate 10 bytes/sec
Five minute output rate 0 bytes/sec
60412 bytes input
480 bytes output
CRC Errors
Data CRC 0
Ringword CRC 0
InvRingWord 0
PcsCodeWord 0
|
Field |
Description |
|---|---|
|
Neighbor |
Switch number of the active member at the other end of the stack cable. |
|
Cable Length |
Valid lengths are 50 cm, 1 m, or 3 m. If the switch cannot detect the cable length, the value is Unknown. The cable might not be connected, or the link might be unreliable. |
|
Link OK |
Whether the stack cable is connected and functional. There may or may not be a neighbor connected on the other end. The link partner is a stack port on a neighbor switch.
|
|
Link Active |
Whether a neighbor is connected on the other end of the stack cable.
|
|
Sync OK |
Whether the link partner sends valid protocol messages to the stack port.
|
|
# Changes to LinkOK |
The relative stability of the link. If a large number of changes occur in a short period of time, link flapping can occur. |
|
Five minute input rate |
The average rate (calculated over a five minute period) at which packets are received, measured in packets/sec. |
|
Five minute output rate |
The average rate (calculated over a five minute period) at which packets are transmitted, measured in packets/sec. |
|
CRC Errors |
Different types of Cyclic Redundancy Check (CRC) errors that are seen on a stack interface:
These errors normally occur when a stack interface state changes due to a switchover or a switch reload. You can ignore such errors. But when these error counters increase significantly or when they increase continuously over a period of time, check the stack cable for issues. |
he following is a sample output when the stack port flaps:
Device# show switch stack-ports detail
1/1 is OK Loopback No
Cable Length 50cm Neighbor 2
Link Ok Yes Sync Ok Yes Link Active Yes
Changes to LinkOK 4
Five minute input rate 0 bytes/sec
Five minute output rate 0 bytes/sec
320 bytes input
80 bytes output
CRC Errors
Data CRC 0
Ringword CRC 0
InvRingWord 0
PcsCodeWord 770
1/2 is OK Loopback No
Cable Length 50cm Neighbor 3
Link Ok Yes Sync Ok Yes Link Active Yes
Changes to LinkOK 1
Five minute input rate 5 bytes/sec
Five minute output rate 1 bytes/sec
2949 bytes input
320 bytes output
CRC Errors
Data CRC 0
Ringword CRC 0
InvRingWord 0
PcsCodeWord 0
2/1 is OK Loopback No
Cable Length 50cm Neighbor 3
Link Ok Yes Sync Ok Yes Link Active Yes
Changes to LinkOK 1
Five minute input rate 0 bytes/sec
Five minute output rate 0 bytes/sec
49375 bytes input
160 bytes output
CRC Errors
Data CRC 0
Ringword CRC 0
InvRingWord 0
PcsCodeWord 0
2/2 is OK Loopback No
Cable Length 50cm Neighbor 1
Link Ok Yes Sync Ok Yes Link Active Yes
Changes to LinkOK 2
Five minute input rate 0 bytes/sec
Five minute output rate 0 bytes/sec
1824 bytes input
160 bytes output
CRC Errors
Data CRC 0
Ringword CRC 0
InvRingWord 0
PcsCodeWord 0
3/1 is OK Loopback No
Cable Length 50cm Neighbor 1
Link Ok Yes Sync Ok Yes Link Active Yes
Changes to LinkOK 1
Five minute input rate 372 bytes/sec
Five minute output rate 7 bytes/sec
111876 bytes input
4613 bytes output
CRC Errors
Data CRC 0
Ringword CRC 0
InvRingWord 0
PcsCodeWord 0
3/2 is OK Loopback No
Cable Length 50cm Neighbor 2
Link Ok Yes Sync Ok Yes Link Active Yes
Changes to LinkOK 2
Five minute input rate 0 bytes/sec
Five minute output rate 0 bytes/sec
80 bytes input
0 bytes output
CRC Errors
Data CRC 0
Ringword CRC 0
InvRingWord 0
PcsCodeWord 0
The following is a sample output when a switch reloads:
Device#show switch stack-ports detail
1/1 is OK Loopback No
Cable Length 50cm Neighbor 2
Link Ok Yes Sync Ok Yes Link Active Yes
Changes to LinkOK 5
Five minute input rate 0 bytes/sec
Five minute output rate 0 bytes/sec
2032 bytes input
320 bytes output
CRC Errors
Data CRC 184
Ringword CRC 187
InvRingWord 120
PcsCodeWord 112
1/2 is OK Loopback No
Cable Length 50cm Neighbor 3
Link Ok Yes Sync Ok Yes Link Active Yes
Changes to LinkOK 1
Five minute input rate 2 bytes/sec
Five minute output rate 0 bytes/sec
24164 bytes input
800 bytes output
CRC Errors
Data CRC 0
Ringword CRC 0
InvRingWord 0
PcsCodeWord 0
2/1 is OK Loopback No
Cable Length 50cm Neighbor 3
Link Ok Yes Sync Ok Yes Link Active Yes
Changes to LinkOK 1
Five minute input rate 0 bytes/sec
Five minute output rate 0 bytes/sec
3024 bytes input
240 bytes output
CRC Errors
Data CRC 0
Ringword CRC 0
InvRingWord 0
PcsCodeWord 0
2/2 is OK Loopback No
Cable Length 50cm Neighbor 1
Link Ok Yes Sync Ok Yes Link Active Yes
Changes to LinkOK 1
Five minute input rate 7 bytes/sec
Five minute output rate 0 bytes/sec
9148 bytes input
480 bytes output
CRC Errors
Data CRC 0
Ringword CRC 0
InvRingWord 0
PcsCodeWord 0
3/1 is OK Loopback No
Cable Length 50cm Neighbor 1
Link Ok Yes Sync Ok Yes Link Active Yes
Changes to LinkOK 1
Five minute input rate 0 bytes/sec
Five minute output rate 15 bytes/sec
1509354 bytes input
27853 bytes output
CRC Errors
Data CRC 0
Ringword CRC 0
InvRingWord 0
PcsCodeWord 0
3/2 is OK Loopback No
Cable Length 50cm Neighbor 2
Link Ok Yes Sync Ok Yes Link Active Yes
Changes to LinkOK 3
Five minute input rate 0 bytes/sec
Five minute output rate 0 bytes/sec
240 bytes input
160 bytes output
CRC Errors
Data CRC 118
Ringword CRC 74
InvRingWord 125
PcsCodeWord 373
In a stack with three members, stack cables connect all the members:
# show switch stack-ports summary
#
Sw#/Port# Port Neighbor Cable Link Link Sync #Changes In
Status Length OK Active OK To LinkOK Loopback
-------- ------ -------- -------- ---- ------ ---- --------- --------
1/1 OK 3 50 cm Yes Yes Yes 1 No
1/2 OK 2 3 m Yes Yes Yes 1 No
2/1 OK 1 3 m Yes Yes Yes 1 No
2/2 OK 3 50 cm Yes Yes Yes 1 No
3/1 OK 2 50 cm Yes Yes Yes 1 No
3/2 OK 1 50 cm Yes Yes Yes 1 No
If you disconnect the stack cable from Port 1 on Switch 1, these messages appear:
01:09:55: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 2 Switch 3 has changed to state DOWN
01:09:56: %STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 1 has changed to state DOWN
# show switch stack-ports summary
#
Sw#/Port# Port Neighbor Cable Link Link Sync #Changes In
Status Length OK Active OK To LinkOK Loopback
-------- ------ -------- -------- ---- ------ ---- --------- --------
1/1 Absent None No cable No No No 1 No
1/2 OK 2 3 m Yes Yes Yes 1 No
2/1 OK 1 3 m Yes Yes Yes 1 No
2/2 OK 3 50 cm Yes Yes Yes 1 No
3/1 OK 2 50 cm Yes Yes Yes 1 No
3/2 Down None 50 cm No No No 1 No
If you disconnect the stack cable from Port 2 on Switch 1, the stack splits.
Switch 2 and Switch 3 are now in a two-member stack connected through stack cables:
# show sw stack-ports summary
#
Sw#/Port# Port Neighbor Cable Link Link Sync #Changes In
Status Length OK Active OK To LinkOK Loopback
-------- ------ -------- -------- ---- ------ ---- --------- --------
2/1 Down None 3 m No No No 1 No
2/2 OK 3 50 cm Yes Yes Yes 1 No
3/1 OK 2 50 cm Yes Yes Yes 1 No
3/2 Down None 50 cm No No No 1 No
Switch 1 is a standalone switch:
# show switch stack-ports summary
#
Sw#/Port# Port Neighbor Cable Link Link Sync #Changes In
Status Length OK Active OK To LinkOK Loopback
-------- ------ -------- -------- ---- ------ ---- --------- --------
1/1 Absent None No cable No No No 1 Yes
1/2 Absent None No cable No No No 1 YesOn Port 1 on Switch 1, the port status is Down, and a cable is connected.
On Port 2 on Switch 1, the port status is Absent, and no cable is connected.
# show switch stack-ports summary
#
Sw#/Port# Port Neighbor Cable Link Link Sync #Changes In
Status Length OK Active OK To LinkOK Loopback
-------- ------ -------- -------- ---- ------ ---- --------- --------
1/1 Down None 50 Cm No No No 1 No
1/2 Absent None No cable No No No 1 No
Cables on a switch that is running properly
Stack ports with a cable that works properly
# show switch stack-ports summary
#
Sw#/Port# Port Neighbor Cable Link Link Sync #Changes In
Status Length OK Active OK To LinkOK Loopback
-------- ------ -------- -------- ---- ------ ---- --------- --------
2/1 OK 2 50 cm Yes Yes Yes 1 No
2/2 OK 2 50 cm Yes Yes Yes 1 No
The port status shows that
Switch 2 is a standalone switch.
The ports can send and receive traffic.
# show switch stack-ports summary
#
Sw#/Port# Port Neighbor Cable Link Link Sync #Changes In
Status Length OK Active OK To LinkOK Loopback
-------- ------ -------- -------- ---- ------ ---- --------- --------
1/1 Absent None No cable No No No 1 Yes
1/2 Absent None No cable No No No 1 Yes
Stack cables connect all stack members. Port 2 on Switch 1 connects to Port 1 on Switch 2.
This is the port status for the members:
# show switch stack-ports summary
#
Sw#/Port# Port Neighbor Cable Link Link Sync #Changes In
Status Length OK Active OK To LinkOK Loopback
-------- ------ -------- -------- ---- ------ ---- --------- --------
1/1 OK 2 50 cm Yes Yes Yes 0 No
1/2 OK 2 50 cm Yes Yes Yes 0 No
2/1 OK 1 50 cm Yes Yes Yes 0 No
2/2 OK 1 50 cm Yes Yes Yes 0 No
If you disconnect the cable from Port 2 on Switch 1, these messages appear:
%STACKMGR-4-STACK_LINK_CHANGE: Stack Port 1 Switch 2 has changed to state DOWN
%STACKMGR-4-STACK_LINK_CHANGE: Stack Port 2 Switch 1 has changed to state DOWN
This is now the port status:
# show switch stack-ports summary
#
Sw#/Port# Port Neighbor Cable Link Link Sync #Changes In
Status Length OK Active OK To LinkOK Loopback
-------- ------ -------- -------- ---- ------ ---- --------- --------
1/1 OK 2 50 cm Yes Yes Yes 1 No
1/2 Absent None No cable No No No 2 No
2/1 Down None 50 cm No No No 2 No
2/2 OK 1 50 cm Yes Yes Yes 1 No
Only one end of the cable connects to a stack port, Port 1 on Switch 2.
The Stack Port Status value for Port 2 on Switch 1 is Absent, and the value for Port 1 on Switch 2 is Down.
The Cable Length value is No cable.
Diagnosing the problem:
Verify the cable connection for Port 2 on Switch 1.
The In Loopback value is Yes.
or
The Link OK, Link Active, or Sync OK value is No.
Stack cables connect all members. Port 2 on Switch 1 connects to Port 1 on Switch 2.
This is the port status:
# show switch stack-ports summary
#
Sw#/Port# Port Neighbor Cable Link Link Sync #Changes In
Status Length OK Active OK To LinkOK Loopback
-------- ------ -------- -------- ---- ------ ---- --------- --------
1/1 OK 2 50 cm Yes Yes Yes 1 No
1/2 Down None 50 cm No No No 2 No
2/1 Down None 50 cm No No No 2 No
2/2 OK 1 50 cm Yes Yes Yes 1 No
Diagnosing the problem:
The Stack Port Status value is Down.
Link OK, Link Active, and Sync OK values are No.
The Cable Length value is 50 cm. The switch detects and correctly identifies the cable.
The connection between Port 2 on Switch 1 and Port 1 on Switch 2 is unreliable on at least one of the connector pins.
| Related Topic | Document Title |
|---|---|
|
Cabling and powering on a switch stack. |
https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9300/hardware/install/b_c9300_hig.html Cisco Catalyst 9300 Series Switches Hardware Installation Guide |
|
SGACL High Availability |
"Cisco TrustSec SGACL High Availability" module of the Cisco TrustSec Switch Configuration Guide |
| Description | Link |
|---|---|
|
To help you research and resolve system error messages in this release, use the Error Message Decoder tool. |
https://www.cisco.com/cgi-bin/Support/Errordecoder/index.cgi |
| Standard/RFC | Title |
|---|---|
|
None |
— |
| MIB | MIBs Link |
|---|---|
|
All the supported MIBs for this release. |
To locate and download MIBs for selected platforms, Cisco IOS releases, and , use Cisco MIB Locator found at the following URL: |
| Description | Link |
|---|---|
|
The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies. To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds. Access to most tools on the Cisco Support website requires a Cisco.com user ID and password. |
The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use the Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required
|
Release |
Feature |
Feature Information |
|---|---|---|
|
Cisco IOS XE Everest 16.5.1a |
Switch Stack |
A switch stack can have up to eight stacking-capable switches connected through their StackWise ports. The stack members work together as a unified system. Layer 2 and Layer 3 protocols present the entire switch stack as a single entity to the network. |
|
Cisco IOS XE Amsterdam 17.3.1 |
Switch Stack |
A new command show switch stack-ports detail was introduced to display detailed information on the stack link of each stack member. |
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