Technical Tip: Understanding 'mclag-port-base' command behavior

[fredery]

Description	This article describes the behavior of the command 'mclag-port-base'.
Scope	FortiSwitch
Solution	The command was introduced in FortiSwitchOS 6.4.2. It was added to address MCLAG interoperability issues with Dell switches using VLTi. Previous behavior: [FortiSwitch A] {port D - ActorPort X} ----| MCLAG |---- [Dell Switch F] [FortiSwitch B] {port E - ActorPort X} ----| MCLAG |---- [Dell Switch G] If the ActorPort number used was the same on both members (identified as 'X' in the simplified diagram), this could result in interoperability problems with the Dell switches using VLTi. New behavior: To address this issue, a CLI command to configure the setting was introduced. Configure the following: config switch global    set mclag-split-brain-detect enable The command will be modified automatically by the system to a value of 64 from a default value of 0: config switch global    set mclag-port-base 64 This makes ActorPort unique for MCLAG members across FortiSwitches and corrects the interoperability issue with Dell switches using VLTi. Notes This is an automatically generated command that cannot be edited. Trying to configure a new value or unset the value will result in an error. config system global unset mclag-port-base end Can not be edited from CLI. attribute set operator error, -651, discard the setting Command fail. Return code -651 After split-brain-detect is disabled, the value will stay at 64. However, this will not have any impact on the FortiSwitch that is now in stand-alone mode.