Operation Manual – IRF FabricH3C S5600 Series Ethernet Switches Chapter 1 IRF Fabric Configuration1-5Caution:z You need to enable the IRF automatic fabric function on all the devices including thenewly added device in the fabric to enable the newly added device to downloadsoftware and discovery neighbors and thus be added to the fabric normally.z You are recommended to set the Unit ID of the switch with the software to bedownloaded to 1, and thus ensure that the candidate switch can download a correctsoftware version.1.1.2 How IRF WorksWhen a fabric is established, the devices determine their respective roles in the fabricby comparing their CPU MAC addresses. The device with the lowest CPU MACaddress is elected as the master and the other devices are slaves.After the election, the fabric can operate normally. The following three functions of IRFcan provide simple configuration mode, enhanced network performance and perfectredundancy backup mechanism for users.I. DDMDistributed Device Management (DDM) is a new device management mode providedby IRF. In normal cases, a fabric can be considered as a single device. You canmanage the entire fabric by logging onto any device in the fabric with different loggingmodes. The devices in the fabric synchronize their configurations by exchangingpackets, thus ensuring stability of the fabric.FTM program uses Unit ID, or device ID to distinguish between the devices in a fabricwhen you manage them. On initialization of the IRF function, each device considers itsUnit ID as 1 and after a fabric connection is established, the FTM programautomatically re-numbers the devices or you can manually configure the Unit ID ofthem.The master in a fabric collects the newest configurations of the user and the slavesperiodically synchronize the configurations from the master. In this way, the entire fabriccan operate with the same configurations.II. DRRDistributed Redundancy Routing (DRR) is used to implement redundancy routingbackup. The devices in a fabric run their independent routing protocols and maintaintheir own routing tables. Unlike a common layer 3 switch, a fabric member does notgenerate a layer 3 forwarding table to forward packets; instead, it uploads the routingtable to the master, which generates a forwarding table used by the entire fabric by
