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Standard User joconnell
(experienced) Wed 11-Oct-17 10:17:56
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Which type of managed switch?


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Other than price, what are the differences between layer 2 and layer 3 managed switches? I understand that they operate at different layers of the OSI network model and that layer 2 operates at the MAC level whereas layer 3 operates at the IP address level, but in practice I don't fully understand what an L3 switch offers over an L2 switch for it's intended use. My home is wired with 24 infrastucture cat5e drops to a patch panel which will be the central node for the below network; I plan on getting a managed switch of some sort to connect to the patch panel and wonder what will do what's required.

The network topology is:
-Broadband Asus WiFi router with a single gigabit wired connection to the managed switch.
-5 port unmanaged gigabit switch to which a TV, PVR and media streamers will be connected, with that switch connected to the managed switch.
-4 port Linksys router configured as a wireless access point (to provide WiFi coverage to upstairs blackspots) to which a network printer, desktop PC, MacBook and Surface devices are connected via it's gigabit ports, with that router connected to the managed switch.
-A 4 bay QNAP NAS device (with 4 gigabit ethernet ports) connected to the managed switch using link aggregation on two cables.
-Two TVs and a media streamer each connected to managed switch.
-In future possibly an IP camera connected to managed switch.
-In future possibly an IP telephone system (assuming such a service is available or will be available to consumers in future).

I'd want all network traffic to not touch the Asus router unless for internet access and the ability to isolate the TV, PVR and media streamers from the rest of the network would be good, but they'd still need to be able to access streaming services provided by the QNAP NAS device within the network.

Is the above achievable and if so, would I need a layer 3 switch to achieve that or could I get away with a layer 2 switch?

I realise this might seem like overkill for a home network, but networking stuff does interest me (maybe 'cos I have a Novell CNE qualification from decades ago) and I'd like my home network to be as fast and secure as possible, so any advice and info would be greatly appreciated.
Standard User prlzx
(experienced) Wed 11-Oct-17 18:02:57
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Re: Which type of managed switch?


[re: joconnell] [link to this post]
 
All switches managed or not operate at layer 2 regardless for the core function of switching.
Unmanaged switch means no user interface.

Then "managed" implies functions such as PoE (layer 1) then VLANs, Spanning tree, Storm control, QoS, MAC ACLs (all layer 2) accessed by web UI and/or CLI for which it needs at least one management IP address.
"Smart" switch is just a limited feature subset of managed.

A layer 2 switch would strictly have no other interaction with IP addresses other than its management address, plus a few clients or services such as DNS, SNMP, SNTP to facilitate management.

A layer 3 switch has some additional functions requiring awareness of the IP addresses of devices connecting through it such as static routes, DHCP server or relay, IGMP for multicast, IP ACLs. It may overlap with the functionality of a router without a strictly defined distinction so protocols such as GRE, OSPF may appear here too.

A layer 3 switch may be able to operate in layer 2 or layer 3 mode according a UI setting.

In a layer 3 role a switch often has a distinct IP address on some or all of the VLANs in which case it can act as a router and answer or relay DHCP requests.

But if it has ability to perform NAT or firewalling it is more likely to be primarily a router rather than a switch.

Outside of the consumer market, something sold as a "router" is much less likely to have a switch chip (ASIC / FPGA) in which case it won't offer those basic layer 2 functions directly through the hardware, though the OS may be able to bridge in software. Wi-Fi is also less likely to be built-in.

For example if you have a separate router but only want traffic to hit that if going to/from Internet, you can use a layer 3 switches to route between VLANs locally. Wi-Fi will still traverse the router unless you have separate access points connected to the switches.

If multiple switches you only need 1 layer 3 switch to act as core and providing internal routing and a default route (pointing via the Internet router). The rest of the switches (aka access switches) only need layer 2 functions.

You can choose to plug end devices into only the access switches but in practice there is no reason not to also use spare ports on the core switch.

Larger or more formal networks may have a strict hierarchy of core, distribution and access switches if it is critical for end devices not to be able to take out the core and distribution layers.

----

I use Cisco SG3xx and 5xx series and even the 3xx series have a selectable layer 3 mode. More expensive models may have some 5G or 10G ports whether trunking / stacking between switches or for end devices.
Currently I have kept all routing, firewalling and NAT functions on routers rather than switches, even for 1000+ devices, but it's useful to know that switches could take over the LAN routing without relying on a router CPU should network demands favour this.



prlzx on iDNET: VDSL / 21CN at ~40Mbps / 10Mbps
with IP4/6 (no v6? - not true Internet)

Edited by prlzx (Wed 11-Oct-17 18:38:27)

Standard User prlzx
(experienced) Wed 11-Oct-17 18:53:22
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Re: Which type of managed switch?


[re: joconnell] [link to this post]
 
IP telephony systems are readily available to any market segment especially if using the hosted variety, you only need 1 or more IP phones and/or SIP/IAX clients (softphones). The PBX function can be a hosted service which has pros and cons, but make forwarding/failover (to PSTN, mobile or Voicemail) and mobility easier.

In general you can buy generic IP phones without being tied to a particular service provider (which still does not preclude experimenting with your running your own e.g. Asterisk / FreeSwitch.



prlzx on iDNET: VDSL / 21CN at ~40Mbps / 10Mbps
with IP4/6 (no v6? - not true Internet)


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Standard User WWWombat
(knowledge is power) Wed 11-Oct-17 19:36:58
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Re: Which type of managed switch?


[re: joconnell] [link to this post]
 
Take a look here: http://www.happyrouter.com/layer-3-switches-explained
That gives something of an understanding of layer 3 switching, but the best summary is this:
the routing functionality of the Layer 3 switch is there to route between different subnets or VLANs on a campus LAN or any sort of large LAN. This means that the Layer 3 switch is really for large Ethernet networks that need to subnet into smaller networks. Most of the time, this is done using VLANs.


The question is going to boil down to whether you have enough devices to need multiple IP subnets. I don't think you do.

If you do, then you may encounter the need for VLANs at layer 2 ... but your unmanaged switches might get in the way of that. Every device on a port on the managed switch would need to be on one VLAN, so every device on an unmanaged switch would need to be on the same VLAN.

In your setup, the QNAP may be the limiting factor, as it would be needed in multiple VLANs ... or in a separate VLAN/subnet of its own.

It does sound like overkill.
Standard User prlzx
(experienced) Wed 11-Oct-17 20:03:03
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Re: Which type of managed switch?


[re: WWWombat] [link to this post]
 
There can still be advantages to separating some functional roles such as voice or cctv or especially guest access each on their own VLAN away from from the main private network even if the sheer number of devices alone do not drive the need to subnet.
This is also true if already relying on devices where security is low down the vendor's priorities which can include some IoT and smart home gear unless they are shamed into fixing vulnerabilities.

But certainly it is a matter of OP choice and understanding each scenario smile



prlzx on iDNET: VDSL / 21CN at ~40Mbps / 10Mbps
with IP4/6 (no v6? - not true Internet)
Standard User joconnell
(experienced) Thu 12-Oct-17 18:53:34
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Re: Which type of managed switch?


[re: WWWombat] [link to this post]
 
In reply to a post by WWWombat:
Take a look here: http://www.happyrouter.com/layer-3-switches-explained
That gives something of an understanding of layer 3 switching, but the best summary is this:
the routing functionality of the Layer 3 switch is there to route between different subnets or VLANs on a campus LAN or any sort of large LAN. This means that the Layer 3 switch is really for large Ethernet networks that need to subnet into smaller networks. Most of the time, this is done using VLANs.


The question is going to boil down to whether you have enough devices to need multiple IP subnets. I don't think you do.

If you do, then you may encounter the need for VLANs at layer 2 ... but your unmanaged switches might get in the way of that. Every device on a port on the managed switch would need to be on one VLAN, so every device on an unmanaged switch would need to be on the same VLAN.

In your setup, the QNAP may be the limiting factor, as it would be needed in multiple VLANs ... or in a separate VLAN/subnet of its own.

It does sound like overkill.

Thanks for that very useful link.

You're right that there aren't enough devices to have multiple subnets, but I would like to keep the media streaming stuff away from the rest of the network, just for the sake of security. I'm not an expert on networking but if achieving that can be done without needing a subnet and just having a separate VLAN for the media streaming devices, then I'd be fine with that, but doesn't a VLAN need a different subnet?

I'm now thinking anyway of going for a layer 3 switch just for the added flexibility, but need to decide on a Cisco 10 port or 20 port device, the former being half the price of the latter. I could get away with 10 ports on the switch but it's mean having only 2 ports spare for any future devices and I'm thinking that if possible, I'd rather have as many devices as possible directly connected to the switch (so a 20 port model) assumng that fits in with what I want to do regarding the separation of the media devices from the rest of the network.
Standard User joconnell
(experienced) Thu 12-Oct-17 18:54:53
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Re: Which type of managed switch?


[re: prlzx] [link to this post]
 
In reply to a post by prlzx:
There can still be advantages to separating some functional roles such as voice or cctv or especially guest access each on their own VLAN away from from the main private network even if the sheer number of devices alone do not drive the need to subnet.
This is also true if already relying on devices where security is low down the vendor's priorities which can include some IoT and smart home gear unless they are shamed into fixing vulnerabilities.

But certainly it is a matter of OP choice and understanding each scenario smile

Thanks, I'm thinking layer 3 switch now, but understanding each scenario will be more work smile
Standard User joconnell
(experienced) Thu 12-Oct-17 18:55:22
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Re: Which type of managed switch?


[re: prlzx] [link to this post]
 
In reply to a post by prlzx:
IP telephony systems are readily available to any market segment especially if using the hosted variety, you only need 1 or more IP phones and/or SIP/IAX clients (softphones). The PBX function can be a hosted service which has pros and cons, but make forwarding/failover (to PSTN, mobile or Voicemail) and mobility easier.

In general you can buy generic IP phones without being tied to a particular service provider (which still does not preclude experimenting with your running your own e.g. Asterisk / FreeSwitch.

Thanks, I'll check them out
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