[mythtv-users] directly connecting HDHR to spare LAN port

Stephen Worthington stephen_agent at jsw.gen.nz
Thu Jun 23 12:16:33 UTC 2022

On Thu, 23 Jun 2022 11:57:16 +0100, you wrote:

>I /did/ start from scratch, remember, with the 16-port switch, doing exactly as you describe. It 
>soon became apparent that the amount of video traffic was overloading the switch. That was when I 
>decided to begin splitting things up, though it has taken four or five iterations. So most of that 
>kit has been acquired over ~11 or so years.

That was a bad switch then - it is generally impossible to overload a
switch.  When you buy one, you should look in the specifications for
the backplane speed.  For my EdgeSwitch ES24 Lite, the specifications
say "Total Non-Blocking Line Rate 26 Gbps".  Since it has 24 copper
ports and 2 SFP ports, all 1 Gbit/s, the backplane speed of 26 Gbit/s
means that all 26 ports can be running at full speed without blocking
happening. I have yet to see a switch where the backplane speed is not
set to be the same as the total of the port speeds, but my guess would
be that your 16-port switch is one like that if high traffic is able
to slow it down.

>This way I can isolate each function without affecting the rest of the network. It has made it much 
>easier to manage.

Using vlans isolates everything - there is no need to actually have
separate switches.  And good smart switches have useful management
features that allow easy management.  In mine, for example, I can name
each port.  Before, I used to have to keep a list of what each port
connected to in a file on a PC.  Now, I just name the port with
something descriptive in the switch's GUI.  This feature actually came
along in a major firmware upgrade that arrived a couple of weeks after
I bought the switch.  If I had known about how useful it is, I would
have had it as a "must have" on the feature list I was shopping for.

>I could have just gone for one humungous 32 or 48 port switch but the cost seems to go up 
>exponentially with the number of ports. There is another point there, the switch would be a single 
>point of failure. Spreading the load improves redundancy no end.

The single point of failure problem is not really solved by having
multiple switches, but it does limit the scope of the damage caused by
one failure.  You really need spares for every piece of equipment if
you do not want to have a failure cause problems, but that is way too
expensive for home users.  I thought about having some spares for
things, but as it is generally possible to buy a replacement and have
it delivered in 2-3 days, I decided that it was not worth it.  But I
have kept my old 16 port switch and old router, so I can create a limp
along network if I get major failures, and keep going until
replacements arrive.

Switches with larger numbers of ports do not increase exponentially in
price unless you are thinking of Cisco or Juniper or the like.  Their
prices start at astronomical and scale up from there.  But in the next
tier down, the prices are fairly linear with a similar cost per port
so a 48 port device will cost twice what a 24 port one does.  And as
far as I can tell if you are just doing normal networking (rather than
an ISP or country backbone), the second tier switches are just as
capable as the Cisco or Juniper ones.  And frequently easier to use.

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