Re: Advice / recommendations on Inexpensive Managed Ethernet Switches
On Thu, Feb 02, 2017 at 11:19:59AM -0500, rhkramer@gmail.com wrote:
> Aside: I am actually gobsmacked (I don't think I've ever been gobsmacked
> before ;-)--in a week of monitoring, we (my son and I, but with my son gone 8
> to 12 hours a day) are downloading 1.5 to 4 GB *per day* (and uploading 100 to
> 300 MB *per day*).
>
> Anyway, I want to try to figure out where all this data is going to and coming
> from, at least in terms of the devices we have on our LAN (I'll discuss those
> below), so I'm thinking that a(n inexpensive) managed (Ethernet) switch or two
> (discussed below) might help me do that.
I think you actually want a smart router. A Debian box with two
or more network interfaces can be such a thing.
> One thing I want to do is implement QOS--we have two ObiHai VOIP devices
> (which we use pretty rarely, but still want to keep--they might be used for 4
> calls / 10 to 30 minutes a week). Sometimes the conversation gets pretty
> choppy, probably depending on what my son is doing at the time (I mean, like
> watching a video or something), so I'm hoping that QOS would improve that
> (assuming the packets from the ObiHai device can be recognized--I would think
> they can based on their (private / on the LAN) IP addresses.
A router can do that better than a switch can.
> Like I mentioned above, the other thing I want to do is start monitoring (at
> least on an occasional / diagnostic basis) the bandwidth used by each device.
Depending on exactly what you want, either a switch or a router
can help here.
> Layout of the network (for background):
>
> The Earthlink DSL modem (Westell) is followed by an Ethernet (unmanaged}
> switch.
You would want to put your router in between these. If you can
arrange a third network interface on the router, you could
connect the WiFi hotspot to the router, as well.
> I see managed 5-port gigabit switches on eBay starting at a little under $30,
> and I'd like to stay close to that as a budget (i.e., ~$60 for 2). Of course,
> if a more featureful switch can monitor the data flows to each device from that
> (central) location, I could spend that ~$60 for the more featureful switch).
> (But there is some value to me to have two managed switches such that one
> would serve as a spare for the central one even if being used at other
> locations for monitoring.)
>
> Advice / comments / recommendations?
That seems an unlikely price point, even for used equipment on
ebay. And managed switches usually have a minimum of 12 ports,
not 5. (12, 16, 24, 32 and 48 are all common)
I would recommend putting in a Debian box between the DSL modem
and the ethernet switch. You will need to learn a little about
routing and IP masquerading / NAT, and you will want to set up
firewalling with iptables.
You can look at traffic in realtime with iftop, which will show
you graphs of the top users by IP address or domain name and
where they are connecting.
You can set individual traffic counters per IP address or per
service or both with iptables.
What you won't get is flow information between local devices,
but as I understand it you are more concerned about traffic
in/out to the Internet at large.
If you set fq_codel as the queue discipline on the interfaces
to the router, you will probably solve most of your traffic
interference problems without mucking with QoS.
-dsr-
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