26 IBM System Storage N series Hardware GuideRLM design and internal Ethernet switch on the controllerThe Data ONTAP management interface (which is known as e0M) provides a robust andcost-effective way to segregate management subnets from data subnets without incurring aport penalty. On the N6000 series, the traditional RLM port on the rear of the chassis (nowidentified by a wrench symbol) connects first to an internal Ethernet switch. This switchprovides connectivity to the RLM and e0M interfaces. Because the RLM and e0M each haveunique TCP/IP addresses, the switch can discretely route traffic to either interface. You do notneed to use a data port to connect to an external Ethernet switch. Set up of VLANs and VIFsis not required and not supported because e0M allows customers to have dedicatedmanagement networks without VLANs.The e0M interface can be thought of as another way to remotely access and manage thestorage controller. It is similar to the serial console, RLM, and standard network interfaces.Use the e0M interface for network-based storage controller administration, monitoringactivities, and ASUP reporting. The RLM is used when you require its higher level of supportfeatures. Host-side application data should connect to the appliance on a separate subnetfrom the management interfacesRLM assisted cluster failoverTo decrease the time that is required for cluster failover (CFO) to occur when there is anevent, the RLM can communicate with the partner node instance of Data ONTAP. Thiscapability was available in other N series models before the N6000 series. However, theinternal Ethernet switch makes the configuration much easier and facilitates quicker clusterfailover, with some failovers occurring within 15 seconds.3.2 N62x0 model detailsThis section gives an overview of the N62x0 systems.3.2.1 N6220 and N6250 hardware overviewThe N62x0 models support several physical configurations (single or dual node) and with orwithout the I/O expansion module (IOXM).The IBM N6220/N6250 configuration flexibility is shown in Figure 3-2 on page 27.
