1-5enables a candidate switch to automatically download the software and change the fabric name in casethat the software version and fabric name of the candidate device and that of the device in the fabric aredifferent, thus reducing the manual maintenance workload.With IRF automatic fabric enabled, if inconsistency in software version or fabric name occurs when aswitch is added to a fabric, the system automatically performs the following operations:z If the software version of the local device is inconsistent with that of the device in the fabric, thesystem automatically initiates a download request to the device with the smallest unit ID in thefabric and downloads the software used by the device in the current fabric to the local device. Thenthe device will automatically restart and be added to the fabric.z If the fabric name of the local device is inconsistent with that of the device in the fabric, the systemautomatically ignores the inconsistency check of the fabric name and adds the device to the fabric.Then the system automatically synchronizes the configurations to the device with the smallest unitID and changes the fabric name.With the above operations completed, the device can be added to the fabric and work normally.z You need to enable the IRF automatic fabric function on all the devices including the candidateswitch in the fabric to enable the candidate switch to download software and discovery neighborsand thus be added to the fabric normally.z If the candidate switch is going to download software from a unit in an IRF fabric, you arerecommended to set the ID of the unit to 1 to make the candidate switch download the software ofcorrect version.How IRF WorksWhen a fabric is established, the devices determine their respective roles in the fabric by comparingtheir CPU MAC addresses. The device with the lowest CPU MAC address is elected as the master andthe other devices are slaves.After the election, the fabric can operate normally. The following three functions of IRF can providesimple configuration mode, enhanced network performance and perfect redundancy backupmechanism for users.DDMDistributed Device Management (DDM) is a new device management mode provided by IRF. In normalcases, a fabric can be considered as a single device. You can manage the entire fabric by logging ontoany device in the fabric with different logging modes. The devices in the fabric synchronize theirconfigurations by exchanging packets, thus ensuring stability of the fabric.FTM program uses Unit ID, or device ID to distinguish between the devices in a fabric when youmanage them. On initialization of the IRF function, each device considers its Unit ID as 1 and after afabric connection is established, the FTM program automatically re-numbers the devices or you canmanually configure the Unit ID of them.
