Wednesday, 25 July 2018

Kings of the Wired Frontier (or when to use >1Gb networks)

Kings of the Wired Frontier (or when to use >1Gb networks)

Most wired network connections are 1 gigabit per second (1Gb/sec or just 1G) using a Cat5e or Cat6(e) cable. In real-world use this allows data transfer of 90-100 megabytes per second (MB/sec). There are many faster ways to connect workstations or storage, but they tend to come with a corresponding increase in price. But when should you use >1Gb networking? And what’s available?

NBASE-T

Also called multigigabit, this is a set of standards that allow faster data transfer without having to upgrade your cables. You can send 2.5Gb/sec over Cat5e or 5Gb/sec over Cat6. In theory this is very attractive, however this is a very new standard and there are few products on the market right now. Most people looking at higher speed networks will jump straight to…

10GBASE-T

A switch or network card that supports 10GBASE-T will allow connections at 10Gb/sec over Cat6 or Cat6e. It is important that all cables and connectors are high quality and Cat6 standard otherwise the connection may drop down to 1G.

SFP+

The options above both send data over twisted-pair cables. SFP+ (Small Form-factor Pluggable) connectors are designed to accept either special cables for short range up to 7m or fibre transceivers for long-distance connections up to 30km. SFP without the + connects at 1G, SFP+ connects at 10G. There’s also a newer standard, SFP28, which connects at 25G.

QSFP+

Quad Small Form-factor Pluggable is the fastest class of connections. QSFP+ connects at 40G. Just as it sounds the connection is made up of four 10G links and it’s usually possible to split a QSFP+ switch port to 4x10G connections with a special cable. There is, of course, also a QSFP28 which uses 4x25G connections for 100G speeds.

But when is all this useful?

Most companies can benefit from their storage system being connected at 10G. Anything bigger than a four bay NAS can probably supply data faster than a 1G connection. Many people will bond two 10G connections together for increased performance and redundancy.

If your workstation or playback machine needs to read data from the network then it should be connected at 10G or faster. A single 10G connection should be able to handle uncompressed HD or 2K playback, but for 4K and above you really need 40G or more. Your storage system also needs to be able to handle the data as well.

For general purpose VFX workstations it’s not essential to connect them faster than 1G. However, as work shifts more towards 4K and beyond it may be worth considering speccing new systems for 10G to future-proof them.