The server access layer is the last mile of the data center network, and link selection affects both cost and stability. Two extremes are common in practice: over-configuring optical modules to drive up costs, or using the wrong medium for cheap, resulting in frequent link interruptions. This article clearly explains the selection logic based on distance and speed.
Set the speed first, then look at the distance
Currently, 25G is generally used for general virtual machine access, and 100G is used for high-performance computing and storage nodes. Distance determines the medium: DAC is preferred for interconnection in the same cabinet or adjacent cabinets within 3-5 meters, with the lowest cost and power consumption; AOC is considered for inter-column cabling from tens to tens of meters; optical modules must be used with optical fiber jumpers across rows and layers, and reach is calculated as single-mode or multi-mode.
Comparison of three access methods
- DAC: e.g.25G DAC high speed cable, plug and play, few fault points, but limited distance
- AOC: The module and cable are integrated, the wiring is neat, suitable for medium distance, the bad end needs to be replaced entirely
- Optical module + jumper: the highest flexibility, equipped withLC-LC 10G multi-mode OM3 two-core jumperor single-mode jumpers to cover long distances
How to choose the port and chip of the network card
The driver compatibility of the network card chip often determines whether the launch goes smoothly. 25G access optionalPCI-EX8 25G dual optical port fiber optic network card (Intel E810 chip), the dual ports are respectively connected to two Leafs for redundancy; the storage and computing separation nodes can be planned according to one port each for the business network and the storage network, leaving an upgrade margin. Electrical port management network cards should also be provided in advance in high-density computer rooms.
The access layer solution recommends using a mixture of three methods to allocate according to scenarios. EB-LINK's DAC, AOC, optical modules and network cards are all in stock and will be shipped after testing one by one. Please call 0755-83179002 for selection consultation.