The Arista MLS layer 2 Arista MLS switch must implement Rapid STP where VLANs span multiple switches with redundant links.
An XCCDF Rule
Description
<VulnDiscussion>Spanning Tree Protocol (STP) is implemented on bridges and switches to prevent layer 2 loops when a broadcast domain spans multiple bridges and switches and when redundant links are provisioned to provide high availability in case of link failures. Convergence time can be significantly reduced using Multiple Spanning-Tree (802.1s) instead of Rapid STP (802.1w) instead of STP (802.1d), resulting in improved availability. Multiple Spanning-Tree Protocol (MSTP) should be deployed by implementing either Rapid Per-VLAN-Spanning-Tree (Rapid-PVST) or Multiple Spanning-Tree MST, the latter scales topologies much better when there are many VLANs.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-255977r882273_rule
- Severity
- Medium
- References
- Updated
Remediation - Manual Procedure
Configure the Arista MLS switch for Multiple Spanning-tree (MST) or Rapid STP to be implemented at the access and distribution layers where VLANs span multiple switches.
switch(config)#spanning-tree mode mstp
The Arista MLS switch can alternatively be configured for spanning-tree mode RSTP to support a spanning-tree instance for each VLAN: