PDF(162.4 KB) View with Adobe Reader on a variety of devices
ePub(211.9 KB) View in various apps on iPhone, iPad, Android, Sony Reader, or Windows Phone
Mobi (Kindle)(893.6 KB) View on Kindle device or Kindle app on multiple devices
Updated:December 11, 2018
The documentation set for this product strives to use bias-free language. For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. Learn more about how Cisco is using Inclusive Language.
Multiple Spanning Tree Protocol (MSTP) Interface Settings on ESW2-550X Switch
Multiple Spanning Tree Protocol (MSTP) is an extension to Rapid Spanning Tree Protocol (RSTP). MSTP enables formation of Multiple Spanning Tree (MST) regions that can run multiple MST instances (MSTI). The MSTP interface settings allow you to configure the port MSTP for every MSTI and display the information learned by the MSTP.
MSTP when compared to Spanning Tree protocol (STP) is faster because it has only two states such as forwarding and blocking which reduces the convergence time.
The objective of this article is to configure MSTP interface settings on ESW2-550X stackable managed switches.
Note: Before you configure the interface settings of MSTP, you should choose the Multiple STP mode of operation. Refer to the article Configure Spanning Tree Protocol (STP) Status and Global Settings on ESW2-550X Switch.
• ESW2-550X • ESW2-550X-DC
MSTP Interface Settings
Step 1. Log in to the web configuration utility and choose Spanning Tree > MSTP Interface Settings. The MSTP Interface Settings page opens:
Step 2. Choose the desired instance you want to edit from the Instance drop-down list.
Step 3. Choose the desired interface to which you want to apply the MSTP interface settings from the Interface Type drop-down list.
Step 4. Click Go.
Edit Interface Settings
Step 1. Click the radio button of the port or LAG you want to modify and click Edit. The Edit MSTP Interface Settings page opens:
Step 2. (Optional) Choose the desired instance from the Instance ID drop-down list.
Step 3. (Optional) Click the desired radio button in the Interface field.
• Unit/Slot and Port — The unit identifies the whether the switch is active or a member in the stack. Unit 1 is active, and unit 2 is a member. If you are unfamiliar with the terms used, check out Cisco Business: Glossary of New Terms. The slot identifies whether the switch is ESW2-550 or ESW2-550X. Slot 1 is ESW2-550, and slot 2 is ESW2-550X. Choose the desired option from the Unit/Slot drop-down list and choose the desired port from the Port drop-down list.
• LAG — Choose the desired LAG from the LAG drop-down list. A Link Aggregate Group (LAG) is used to link multiple ports together. LAGs multiply bandwidth, increase port flexibility, and provide link redundancy between two devices to optimize port usage.
Step 4. Choose the desired priority from the Interface Priority drop-down list. The priority value determines port choice when a bridge has two ports which can form a loop. The port with lower priority is chosen as the forwarding port and the other port is blocked.
Step 5. Path cost is calculated by the bandwidth between the switches. Root port is selected based on the path cost. The port with the lowest path cost to the root bridge becomes the root port. Click the radio button that corresponds to the desired path cost in the Path Cost field.
• Use Default — Use the default cost generated by the system.
• User Defined — Enter a value for the path cost in the User Defined field.
The following information is displayed:
• Port Status — The RSTP status on the port chosen.
– Disabled — STP is disabled on the port.
– Blocking — The port is blocked. The port cannot forward traffic or learn MAC addresses. The port can forward BPDU data.
– Forwarding — The port can forward traffic and can learn new MAC addresses.
• Role — The role of the port assigned by the STP to provide STP paths. The available roles are:
– Root — It has the lowest cost path to forward packets to the Root Bridge.
– Designated — The interface through which the bridge is connected to the LAN, which provides the lowest cost path from the LAN to the Root Bridge.
– Alternate — Provides an alternate path to the Root Bridge from the root interface.
– Backup — Provides a backup path to the designated port. Backup ports are also used when a LAN has two or more established connections to a shared segment.
– Disabled — The port is not participating in Spanning Tree.
– Boundary — The port is a boundary port. The boundary port is allocated its state from the instance 0.
• Mode — The current mode of spanning tree such as Classic STP or RSTP.
• Type — The types of the MST port are:
– Boundary — The port attaches MST bridges to a LAN in a remote region. It indicates whether the device connected on the other side of the link uses a RSTP or STP mode.
– Internal — The port is an internal port.
• Designated Bridge ID — The ID of the bridge that connects the shared LAN to the root.
• Designated Port ID — The ID of the designated bridge that connects the shared LAN to the root.
• Designated Cost — The port cost in the STP topology. If the cost is low then, when STP detects a loop there is less of a chance that the port is blocked.
• Remaining Hops — Number of hops till the next destination.
• Forward Transition — The number of times the port has changed from forwarding state to blocking state.
Step 6. Click Apply.
Copy MSTP Interface Settings
Step 1. Click Copy Settings to copy the settings of one interface to others. The Copy Settings window appears:
Step 2. Enter the interface or a range of interfaces to which the configuration is copied in the provided field.