JN0-1301: Data Center Design, Specialist

A top-of-rack deployment installs switching equipment in each individual rack. This makes each rack a self-contained management unit and keeps server-to-switch cabling as short as possible.

A LAG in a Virtual Chassis Fabric can include member links located on different member switches. Connecting each server’s two LAG links to separate ToR switches therefore preserves connectivity if either a link or one ToR switch fails, while the fabric operates as one logical device.

Junos Fusion Data Center provides a data-center fabric architecture that supports a combination of up to 64 supported QFX and EX top-of-rack satellite devices, with QFX10000 switches in the spine layer. A 60-device mixed EX/QFX deployment therefore fits its supported scale and intended use.

Valid eBGP fabric ASN plans include assigning a unique ASN to each device and assigning one ASN to all leaf devices with a separate ASN for all spine devices. In both designs, every leaf-to-spine adjacency has different ASNs, so it is an eBGP session. A single ASN on every device would instead form iBGP sessions.

Equipment should be installed so that its airflow is consistently directed from the cold aisle to the hot aisle, irrespective of port-panel location. Hot-aisle/cold-aisle layouts separate supply and exhaust air: cooled air enters equipment from the cold aisle and heated air is exhausted into the hot aisle. This separation reduces hot-and-cold air mixing and makes more effective use of the cooling system’s capacity.