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I have 4 "NETGEAR ProSafe GS724T Gigabit Smart Switch" that will need connecting to each other. I am not sure of the best way to go about this. Normally, I would just daisy chain them or hook all switches into 1 switch so there is only one hop for data.

Is there a better way to connect these switches?

For Info: Network traffic is for about 30 people running databases, accessing files, VoIP phones ect over the network.

If any more information is needed then please let me know.

Thanks

webnoob
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3 Answers3

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Daisy-chaining's not a good idea for connecting more than a couple of switches; if you do something like sw1->sw2->sw3->sw4, then users on sw1 have to share the bandwidth of sw1's connection to sw2 between them. Users on sw2 have to do the same with sw2's connection to sw3, except that their link also has to accommodate all the traffic from sw1. By the time you get to sw4, the uplinks from switch to switch can easily become congested as the traffic from all three of the other switches gets stuffed through it. Not a great result, especially if you need guaranteed available bandwidth for your VoIP traffic.

Your second idea is better; connect sw1/2/3 to sw4 and rely on spanning tree to disable any loops; unfortunately, I don't think GS724Ts support any kind of port aggregation, so you'll be limited to 1Gb/s for all your links, whether user to switch or switch to switch.

RainyRat
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  • When you say limited to 1GB for all my links, does that mean per port or for all the switches? – webnoob Sep 06 '11 at 13:26
  • All the ports on the GS724T are 1Gb/s, and you can't combine them into trunks/channels, so the most you'll be able to get out of any one port will be 1Gb/s regardless of whether it's a user or another switch attached to it. If you only have one link into a switch, the most you'll be able to get data into it will be at 1Gb/s – RainyRat Sep 06 '11 at 13:34
  • Ok I understand. I take it there would be no way around this problem without having stackable switches? What would Port Aggregation offer that would help? – webnoob Sep 06 '11 at 13:39
  • Port aggregation (or link aggregation, etherchannel, trunking, teaming or the various other names it goes by) lets you combine multiple ports into one logical port with more bandwidth. For example, the core switching fabric in my office is two gigabit switches with 4 ports connecting them, providing a 4Gb/s backbone between those two switches. I don't know if GS724T supports trunking; you'll need to check your documentation to see if it's possible. – RainyRat Sep 06 '11 at 13:59
  • Port aggregation would allow you to aggregate 2 links between the switches together, giving you effectively a 2Gb link between them, plus redundancy in the event of one of those links failing. – hmallett Sep 06 '11 at 14:02
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The data sheet for the switch provides the following information:

• Dedicated SFP ports provides fiber uplinks without sacrificing any downlink Gigabit port. Up to 4 SFP ports provide not only redundant uplinks, but can also build dual redundancy by a trunked uplink with link aggregation and failover, the dual-redundancy, a powerful design for the network virtualization

chicks
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Dale Forguson
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Some switches have specific ways they like to be connected together (or stacked), which may give advantages such as allowed them all to be managed as a single unit, or a faster interconnect between the switches. The Netgear switch in question doesn't have this however, so they can be seen as normal standalone switches.

As the switches support Spanning Tree Protocol you are not limited to simply daisy-chaining them together, and you can introduce potential loops into the system for redundancy. I think that if you do this it is best to increase the STP priority of one of the switches.

I think that unless you have some reason for needing a full mesh (connect each switch to every other switch), which would use up 12 switch ports, I'd probably just use a loop, connecting switch 1 to switch 2, switch 2 to switch 3, switch 3 to switch 4, and switch 4 to switch 1.

hmallett
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  • Won't spanning tree detect this as a loop and disable it? This would leave a simple daisy-chain instead of a loop. Also, if you want to set the root of your spanning tree manually, it's the lowest ID that wins, not the highest. – RainyRat Sep 06 '11 at 13:18
  • I think he suggested that because it allows redundancy. STP will disable the loop until something goes wrong with one of the switches and the loop would no longer be present and a redundancy system would be in place (at least, that is how I understand it). – webnoob Sep 06 '11 at 13:29
  • Spanning tree would indeed disable the loop, but would retain intra-switch connectivity should one of the interlinks fail. As for STP priority, yes you increase the priority by lowering the ID. – hmallett Sep 06 '11 at 13:31
  • I presume I would have the lowest ID as the one running the servers ect? i.e Where the most data would be requested / sent? – webnoob Sep 06 '11 at 13:40
  • I don't think it actually matters. I set the switch at the core of our network to be the root, but that's simply a choice I've made. – hmallett Sep 06 '11 at 13:44
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    Depending on your network topology, the location of the root bridge can CERTAINLY matter. To take a pathological case, let's say one of your access switches becomes the root. If its distribution switch is connected to both core switches, those big fat aggregated links between your core switches won't be part of your network. Oops! For this question, it doesn't matter so much however. – MikeyB Sep 06 '11 at 14:20
  • It's a good idea to make sure that your STP root is explicitly configured rather than left up to chance. Otherwise lowest MAC address (i.e, oldest switch) wins. Placing the root switch at the logical centre of the network makes sense, too. – RainyRat Sep 06 '11 at 14:20