[SOLVED] Switch to Switch Link - Best Option


Jun 12, 2016
Hello Everyone,

This is probably a really basic question for the network engineers here but I want to make sure I'm not doing something rather daft!

Basically I have two switches in the loft of my house - both are Netgear managed switches, one is a gigabit with SFP+ plus ports, other is a 10 Gig again with SFP+ ports.

I need to run cables right down from the loft to under the floor on the ground floor where there will be another managed switch but this one will be gigabit only.

I'm going to use Fiber Optic cables (OM4 LC-LC Multimode) - each is 30M. I'm planning to run two down so I have redundancy if one cable fails or something.

The purpose of these cables is to connect one switch to the other so my understanding is that the cable's speed and port negotiation speed (gigabit) is essentially the maximum switch to switch throughput.

I initially thought I'd use more than one fiber cable to increase the capacity (essentially having multiple links between the underfloor switch and the loft switch) but I've read that this is a terrible idea UNLESS I use Link Aggregation which I believe involves "bonding" the ports so they act as one port, increasing the switch to switch throughput so if two were bonded, that's essentially 2gbps from switch to switch with two ports?

The reason the switch to switch link is so important is I plan to add about 12-16 cameras 4K minimum into the switch under the floor but the DVR for the cameras will be in the loft (cameras are wired POE not wireless).

First question - if all the cameras so let's say 16 cameras are sending recordings to the DVR, how much bandwidth is that putting on the switch to switch link? Am I going to be anywhere near say 1gbps or 2gbps if it's aggregated. Also, if I were to upgrade the camera quality to say 8K cameras down the line or add additional cameras, is this going anywhere near the bandwidth?

The link will also be used to supply normal internet data too to wireless access points (wired backhaul, wifi 6 easy mesh) under the floor on the ground floor too so I don't want the link being too slow to handle all the data as the router is connected to the loft switch.

Second question - what is the best way to achieve link aggregation? Not used it before but I've read there's different types for failover, speed etc - I'm mainly after speed and efficiency over failover?

Obviously if I'm going to be near the limits of bandwidth with this setup then I'd have to buy another 10 Gig switch, upgrade the transceivers to 10 gig SFP+s and I'd imagine that should be more than enough, especially if I link aggregated again - this is of course an option for the future if the demand expanded but the price of these switches is still a bit naughty! :)

I know as well for a 30m run I probably could have got away with Cat 7 but I thought it makes sense to use OM4 Fiber given the reduced risk of interference, faster speeds for the future, lower latency etc.

Any advice greatly appreciated - it maybe my layout is totally wrong here but I can't see any other way of connecting two switches together unless I'm missing something?

Many thanks :)
There is no way to say for sure how much bandwidth. Almost all cameras are compressing the data before they send it. In some ways I wish mine wouldn't since they tend to lose quality when there is a lot of change on the screen.

My guess is it will be far below 1gbit. If your dvr machine is using a actual OS you likely can see the data rates on each camera. Best to watch when it is very sunny with lots of moving shadows. Windows you can see the rates for each session in the network tab of the resource manager.
Your DVR must also be able to take more than 1gbit both ethernet as well as your disk systems. It takes very special disk systems to be able to keep up with say a actual 10gbit data. Most these use SSD which is never really going to be a option for DVR with the massive amount of data kept.

Cat7 is a waste of money really. It never was fully certified and provides almost no benefit over cat6a. Cat6a is rated to 10gbit at 100 meters. Fiber mostly is used to go more distance. This is going to be a cost thing more than anything else. Fiber also must be more protected especially if you are going to use a patch cable rather than fiber actually designed to run in the walls. Generally if you are having to buy everything you go cat6a. If you already have parts of the fiber stuff then you do the math.

If your ports are SFP+ that means they are 10g, the ones with out the "+" are only 1gbit.

Port aggregation does not work well. It uses a mathematical formula based on ip and port numbers to select the path. It does not care about utilization so it can put all the traffic on 1 link and let other idle. It is best used when you have a central server talking to many remote machines with many open sessions. The random of all
the ip and session ports will help to balance the load to some extent.

You can use port aggregation as a form of redundancy. It will fail over faster than spanning tree. It is kinda silly though if both your fibers follow the same path. This is more used in data centers to provide redundancy of the actual switches as well as the fiber and cables. It also allows a switch to have say software patch applied without taking down some data centers. For home use the complexity of setting up even partial redundancy will likely cause more outages than not even doing it. Switches and fibers and even ethernet cables seldom fail.


Mar 16, 2013
Regarding cameras and LAN bandwidth:

I have 2x Reolink RLC-423 cameras on the outside of house.
Soon to be 3 or 4.

Connected to and recording directly to my QNAP NAS, at their max resolution of 2560x1920, 30fps. Bitrate of 6144Kbps.

This is the incoming bandwidth from both of them combined.


Jun 12, 2016
Thank you both for replies, really helpful!

It looks like I'm going to be absolutely nowhere near the max bandwidth then and that's not even taking into account compression by the camera's software.

I'll avoid Link Aggregation and just run in the cables - it's luckily a straight run from top to bottom and going to put conduit in so I'll run the fiber through that and jobs a good'in!

Thanks again :)