Hello, everyone!
Today, I will continue to explain data center cabling. In this article about data center cabling, I will explain basic architecture.
Generally, data centers use three kinds of cables: AC/DC power cables, ground cables, copper (UTP and/or coaxial) cables and optical cables (SM or MM fibers).
In the data center, interconnected servers, storages, switches can have a large number of connections. In this way, redundancy is achieved. It is rare to increase the transmission capacity in this way because it is done with proper cables. This network is called a mesh network because it looks like a mesh. This means that there are many cables in the data centers.
There are a large number of servers in the data center, which is why
the switch architecture is used. Access switches connect a group of
servers to interconnection switches, as shown in the following
figure.
Figure 1. Switch architecture
Some architectures add a third level of switches, but it becomes very complicated, expensive, consumes a lot of power and produces a lot of heat. This architecture is called “fat-tree” or “Spine-leaf”, too. Interconnection switches have different names: aggregation or core switches. Access switches have second name edge switches.
Servers that can be connected directly to storage area network (SAN) switches or via access and/or interconnection switches.
There are several standards that apply to data center cabling. These are TIA-568 and ISO11801, ISO 24764, CENELEC EN 50173 and TIA-942.
The two most common designs are "top-of-rack" and "end-of-row." In the first case, "top-of-rack" (figure 2.), servers and switches are in the same rack and their connection requires very short connections. In these situations, copper cables - UTP or CX-4 - can be used. Of course, fiber optic cables can be used anytime, anywhere. The use of copper cables in this design is a limiting factor in terms of data transfer speed - maximum 25 Gbps.
Figure 2. Top-of-rack
Figure 3. End-of-row
In the second design (figure 3.), the servers are in one rack, the switches are in the other rack. Connections between devices can be realized with copper cables up to 10 Gbps or optical fibers without restrictions.
I will continue to explain this theme in the next article >> Data center cabling (3): Copper cables.
Thank you!
