JN0-1300: Data Center Design, Specialist (JNCDS-DC)

A non-oversubscribed QFX3000-M design using QFX3600 nodes requires sufficient 40-Gbps host-facing capacity and an equal amount of fabric uplink capacity. Eight QFX3600 nodes supply up to 64 40-Gbps host-facing connections, enough for 30 servers with two links each, while two 40-Gbps FTE links from every node to each of four QFX3600-I interconnects provide eight 40-Gbps uplinks per node. That gives 320 Gbps of fabric capacity per node, matching its 320 Gbps of host-facing capacity. Juniper documents that a QFX3600 node can use up to eight uplinks to QFX3600-I interconnects and that a QFX3000-M supports a maximum of four QFX3600-I interconnects.