The better option is to install the switches, and any related structured patch cabling, in the middle of the rack – around the 23-25U mark, and not top-of-rack switches placement.
The top of rack switches are installed at the top. However, people tend to stick to the concept of “TOP” of rack religiously. One of the aims of installing ToR switches into each rack is to reduce cabling – cables which would otherwise reduce airflow, be bulky and difficult to manage, under risk of damage (such as crushing or excessive bending caused by cables near it) and generally ugly. The uplinks from ToR switches to core switches can then be 10 gigabit links utilising AOC, Twinax or bonded/trunked connections to achieve backbone speeds of over 150Gbps – far higher than possible (or needed) from a single server. This increased density would eventuate in such a mass of copper cabling in each rack, that it makes sense to consolidate this in to two or three ToR switches per rack. This is not only because servers are smaller, but also each one will have multiple links – such as bonded links, out-of-band management and virtual hosts participating in multiple networks. Top of Rack switches have come about as a result of increased density of servers and networking within a 42RU rack, where in the 90’s and 00’s there may be 5-15 servers in a rack – each with one or two network connections, in the second decade of 2000, there are more likely to be over 80 network links in a single rack. ToR switches are often 1RU and approximately 48 ports – this would provide one uplink for each server if all 42RU of a rack is filled with 1 RU servers.
The ToR switches will allow servers to communicate with each other directly, and therefore reduces overall traffic on core switching. It’s the practice of placing a physical switch within each rack, so that the network switching for the rack is close to the servers or devices that need to connect to it.
You may know about ToR, top-of-rack (for) switches.
0 kommentar(er)
