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I want to set up a fast network and am considering options.

I want a backbone switch that connects all my switches together. I can see options for SFP / SFP+ ports. Some SFP ports are 1 or 2 Gb from what i can tell and 10Gb SFP+ ones are expensive. Is it worth me maybe just using 2gb SFP ports to 2 - 4 smaller switches as to allow for up to 4/8GB across the network at lower costs?

How also is best to connect these together I have been in the past connecting a single link from a main switch holding servers and routers etc to the end user switches. I am seeing videos however on youtube like this:

https://www.youtube.com/watch?v=CPoMG9DjY3o

These seem to show the switches connecting in a triangle or star shape depending how many switches and each switch is interlinked giving more than one route. So want to check this is possibility on just Managed switches and does it need much configuration?

Network Proposal

Example

I am thinking something like this but should the 24 port switches be connected together as the youtube video guy suggests and could i possibly use LACP insteap of the SFP / SFP+ for similar performance just need a lot more ports on the Main switch?

Preferred Setup

I'm not interested in what products to be used here but want them speced similar to below:

1 x https://www.amazon.co.uk/NETGEAR-ProSAFE-10-Gigabit-Ethernet-XS708T-100NES/dp/B01ELW0QM4/ref=sr_1_3?s=computers&ie=UTF8&qid=1521221816&sr=1-3&keywords=SFP%2B+8+port&refinements=p_89%3ANETGEAR

2 x https://www.amazon.co.uk/NETGEAR-GC728X-100EUS-Insight-Managed-Ethernet/dp/B0788C5QVN/ref=sr_1_40?s=computers&ie=UTF8&qid=1521213723&sr=1-40&keywords=SFP%2B&refinements=p_89%3ANETGEAR&th=1

Budget Alternative

But to cut costs (And as possible above is overkill i think) i am trying to find LACP alternative and am looking at the spec required for main switch to get the most out of something like the below with LACP support:

2 x https://www.amazon.co.uk/NETGEAR-FS728TLP-Rackmount-Power-over-Ethernet-Protection/dp/B00F3XSNPS

I'm also confused if the combo ports are only ports than can support LACP and seem to indicate if combos with SFP port so would need a main switch with 2 x sets of those exact combo ports?

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  • Please provide a network diagram and also what type of equipment you are using.
    – user36472
    Commented Mar 16, 2018 at 16:16
  • I haven't decided on equipment but will probably be Netgear Managed Switches with SFP ports that are 2GB if that is a thing think i have seen them about.
    – harri
    Commented Mar 16, 2018 at 16:43
  • @Cown i have attempted a diagram of my thoughts so far and added to question
    – harri
    Commented Mar 16, 2018 at 16:44
  • Product or resource recommendations are explicitly off-topic for SE sites, except on Software Recommendations and Hardware Recommendations, so we cannot tell you which devices to use.
    – Ron Maupin ♦
    Commented Mar 16, 2018 at 17:47
  • Ok sorry didn't know that can i reword to speced like? Im more interested in what ports are needed like if in the above are the combo ports used for LCAP and so would need 2 sets of combo ports on the basckbone?
    – harri
    Commented Mar 16, 2018 at 17:49

1 Answer 1

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Your ethernet SFP/SFP+ for fiber are going to be 1 or 10 Gbps. There isn't a 2 Gbps ethernet fiber SFP (some vendors used to count this way because of full duplex, but it is still 1 Gbps in each direction).

You may be able to use LACP, depending on the switch vendor/model. Combining multiple interfaces into a single channel is really just fooling STP to make it look like the multiple links are a single link.

Each traffic flow will still use a single link of the channel, but in aggregate, you will be able to use the higher bandwidth of the channel. There is a hash algorithm that determines which flow uses which channel link.

On switches that support LACP, this is a fairly straight-forward configuration. Without the specific switch models, we cannot help you to configure it.

The current best practice is to only connect the access switches to the distribution switches, not to each other. You should then have a VLAN only on the distribution switch and one access switch. An access switch can have multiple VLANs, but those VLAN should not be on any other access switch. You restrict this on the trunk links. This helps to prevent STP problems.

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  • So basically yeah LACP will help say 4 x 1GB to each access switch will allow 4 users to max out 1Gb each but never 1 user 4Gb as can only use one link?
    – harri
    Commented Mar 16, 2018 at 16:50
  • So is that guy in the video a bit confused as he has confused me as to why he interlinks the switches.
    – harri
    Commented Mar 16, 2018 at 16:51
  • Basically, but a single user could have multiple flows. It depends on the hashing algorithm used. For example, if the algorithm used takes into account both the source and destination IP addresses, then it is possible that a user would connect to two separate devices at 1 Gbps. Usually the algorithm used will use both the source and destination IP addresses, and the source and destination transport ports. It is per traffic flow, and it depends on how you define the flow for the algorithm.
    – Ron Maupin ♦
    Commented Mar 16, 2018 at 16:54
  • Im thinking LACP and 4 x 1Gb links from backbone to each access switch then to save costs as those SFP+ switches are like 500 compared to 150. Also my server will only have max 4 x 1Gb connections.
    – harri
    Commented Mar 16, 2018 at 16:58
  • Cisco did a study, and they recommend that you have a 20:1 access to distribution bandwidth ratio. That means that for every twenty 1 Gbps access interfaces, you have 1 Gbps in the access switch uplink to the distribution switch. With a 48-port switch, you would need 2.8 Gbps in the switch uplink. Your channels should optimally (for the hash) be installed in a power of 2 (1, 2, 4, or 8 links). for 2.4 Gbps, that would be four 1 Gbps links, or one 10 Gbps link. I think the 10 Gbps SFP+ are around twice the 1 Gbps SFP, so it may be cheaper for the 10 Gbps SFP+.
    – Ron Maupin ♦
    Commented Mar 16, 2018 at 17:04

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