Cisco Catalyst 9300 Series: Руководство по управлению стеками коммутаторов

Restrictions for Switch Stacks

Managing Switch Stacks 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. Prerequisites for Switch Stacks, on page 1 Restrictions for Switch Stacks, on page 1 Information About Switch Stacks, on page 2 How to Configure a Switch Stack, on page 8 Configuration Examples for Switch Stacks, on page 10 Feature History for Switch Stacks, on page 23 Prerequisites for Switch Stacks • 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. Restrictions for Switch Stacks 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. Managing Switch Stacks 1

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Changes to Switch Stack Membership

• You cannot have a switch stack containing a mix of different license levels. Information About Switch Stacks Switch Stack Overview 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. Switch Stack Membership A standalone device is a device stack with one stack member that also operates as the active switch.

You can connect one standalone device to another to create a device stack containing two stack members, with one of them as the active switch. You can connect standalone devices to an existing device stack to increase the stack membership. Hello messages are sent and received by all stack members. • If a stack member does not respond, that member is removed from the stack. • If the standby device does not respond, a new standby device is elected. • If the active device does not respond, the standby device becomes the active device. In addition, keepalive messages are sent and received between the active and standby devicees.

• If the standby device does not respond, a new standby device is elected. • If the active device does not respond, the standby device becomes the active device. Changes to Switch Stack Membership 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. Managing Switch Stacks Information About Switch Stacks Managing Switch Stacks 2

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Stack Member Numbers

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 . Stack Member Numbers 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. Managing Switch Stacks Stack Member Numbers Managing Switch Stacks 3

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Stack Member Priority Values

• 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.

Stack Member Priority Values 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. We recommend assigning the highest priority value to the device that you prefer to be the active switch. This ensures that the device is reelected as the active switch if a reelection occurs. Note 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. Managing Switch Stacks Stack Member Priority Values Managing Switch Stacks 4

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