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Arista

Discovery task stops when it hits a VLAN that is not assigned to any ports

IP Fabric Version: All

Known Affected platforms: Arista EOS, Platform 7280sr3, Version 4.26.4M

Description: The command show spanning-tree vlan detail stops when it hits a VLAN that is configured on the device but is not assigned to any ports (exception is the default VLAN 1). This has been seen when running rapid-pvst spanning-tree but could possibly affect other versions.

Example

arista#show vlan
VLAN  Name                             Status    Ports
----- -------------------------------- --------- -------------------------------
1     default                          active
2     BAD_VLAN                         active
5     GOOD_VLAN                        active    Et1, Et2
arista#sho span vlan det
Spanning tree instance for vlan 1
 VL1 is executing the rapid-pvst Spanning Tree protocol
  Bridge Identifier has priority 4096, sysid 1, address 0000.0000.0000
  Configured hello time 2.000, max age 20, forward delay 15, transmit hold-count 6
  We are the root of the spanning tree


No spanning tree information available for vlan 2

Result: Incomplete IP Fabric Path Lookups.

Temporary Fix: Remove the unused VLAN from the configuration using the no vlan # command.

Permanent Fix: Unknown. Waiting for a response from Arista.

Wrong E2E Path Lookups due to bug in EOS which assigns the same STP ID to different interfaces

IP Fabric Version: All

Known Affected platforms: Arista DCS-7504N, 4.28.6M-30705735.4286M, DCS-7280SR-48C6-F, 4.26.4M-25280047.4264M

Description: Arista is assigning the same STP ID to different ports. To serve its purpose spanning tree port ID needs to be unique in a L2 domain. Under some circumstances, e.g. when device operational requirements break its maximum scalability limits or due to a bug in device operating system, a device may assign the same spanning tree port ID to more ports in a single L2 domain. This situation was observed e.g. on Arista DCS-7504N running software image with internal build version 4.28.6M-30705735.4286M. In IP Fabric this has resulted in wrong STP topology calculation and consequent issues in path lookup.

Result: Incomplete IP Fabric Path Lookups.

Temporary Fix: None.

IP Fabric fix Version: To be specified.