Multigig is the term for a link that runs at speeds of more than 1G on existing Cat5e and Cat6a copper cables. Everyone is used to running gigabit connections on these cables, but this technology will allow higher speeds – 2.5G and 5G – and with no need to run a new class of cable, or fiber. If you have Cat6a, some Multigig implementations will even run 10gig over that copper. Your mileage on this particular speed may vary.
Short version – Multigig allows you to run 2.5, 5, and maybe 10G on your existing copper cable installations.
Technically, this is called NBASE-T 802.3bz – but since no one is going to remember that, everyone is sticking with ‘MultiGig’.
The main benefit of Multigig right now is in places where the latest and greatest WLAN Access Points are being deployed. Both 802.11ac Wave 2 and 802.11ax access points can provide well in excess of 1G of aggregate throughput. 802.11ac has a practical speed of 1.7-2.5Gbps, and 802.11ax , as it rolls out, promises to be significantly faster, with speeds per stream of up to 3.5Gbps.
These are very fast WLAN technologies. You can put users on these access points, and really take advantage of 3.5Gbps of bandwidth for each access point; the connection to the switch is now the bottleneck.
The connection on a standard switch is only 1Gbps. This is a hard limitation on how much bandwidth goes to an access point.
What good is a 2.5Gbps 802.11ac wireless access point if the uplink to the switch is only 1Gbps?
There are two choices. If you want to get more bandwidth to your AP, you need to either have an AP with 2 ethernet ports and trunk them – AND use twice as many switch ports – and the associated cost of cabling using 2 cables per AP has to be counted. And to make it workse, you still only get 2Gbps on an AP that will do 2.5Gbps , or more, if you are getting new 802.11ax equipment. Hardly an efficient use of cables, equipment, or bandwidth.
This is a real issue – its costly, and it makes 802.11ac and better a little more difficult to rationalize; both small and largescale WiFi deployments are suddenly using twice as much infrastructure – that’s a significant increase in cost, and a lot of points to fail, and tough places to troubleshoot.
Instead – use a switch that can run 2.5Gbps on a single link – and it will work on existing, older Cat5E cable. There are 1.7-2.5Gbps capable 802.11ac WiFi systems, and these can be purchased, installed, and connected to the switch with one existing cable. If the switch is equipped 5Gbps capability, there’s both the initial 2.5Gbps with all the .ac Wifi systems, and then there are additional faster speeds as 802.11ax systems are deployed.
This is also going to assist with IoT devices as they come online; many of these will be designed to take advantage of Multigig infrastructures; having a 1G bottleneck at the switch, or requiring fiber to be run everywhere to get higher bandwidth just doesn’t make sense.
Multigig switching helps futureproof the infrastructure; 2.5Gig and 5Gig speeds on existing cables have the potential to breathe new life into your wired infrastructure while you expand and improve WiFi, while providing the ability to add in high-bandwidth IoT capabilities as they arrive – without replacing your cabling plant.