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Guidance needed - managed switches

Guidance needed - managed switches

Old Jul 25, 18, 10:03 am
  #1  
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Guidance needed - managed switches

My home network is fairly complex: an air-gapped gigabit network for the RAID server for my docking stations and desktops, another gigabit network to the same places with internet access, and a third (10/100) network to the printers. Yeah, it's overkill, but my junk box is probably bigger than yours, and it's a hobby, so ...

Last weekend I was at an electronics flea market and I came across a 24-port gigabit switch (Nortel 3510-24T). I told the guy it's nice but my setup needs different networks, etc. He said no problem - just set up separate VLANs. Then the penny dropped - of course! It's a managed switch!

So, thinking it might be a useful skill to acquire, I bought it (ten bucks), took it home and checked it out. It all seemed OK. Now to configure it.....

Internet searches revealed a number of websites, but they seem to be populated by guys who already know what they're talking about talking to other guys who already know what they're talking about. Just getting past the jargon took a bit of time.

So ... can anyone suggest any resources (a book like "Managed Switches for Dummies" would be nice ) or tutorial websites, etc.? I'm a pretty fast learner, but I need a place to start.

TIA
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Old Jul 25, 18, 12:54 pm
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A generic Networking for Dummies book probably talks about it, but here's the idea:

VLAN (virtual local area network) is a way to use the same physical switches and cables and have multiple independent and segregated networks running on them. VLAN-aware switches modify each Ethernet frame that passes through them to include a VLAN ID. This is called tagging the frame. The spec says the tag can be a number between 0 and 4095, so you can theoretically have up to 4096 VLANs coexisting. Many cheaper switches can't do the full range, however. In addition, VLANs 0 and 1 are usually reserved for special applications, so it's bad form to use them. If you run tagged traffic through a switch that isn't VLAN-aware, it will often think the frames are garbled and drop them. So if you want to use tagged traffic, you have to pass that traffic through only switches that are designed for it.

There are two kinds of traffic you can pass: tagged, which has the VLAN ID attached, and untagged, which doesn't. Generally on a managed switch, you define which ports are members of which VLAN, and whether they pass tagged or untagged traffic on that VLAN. PCs, printers, and other end-user devices generally can't read tagged traffic (though Linux/Unix can if you set them to), so any port that is directly connected to such a device must be set to untagged. Broadly speaking, there are three main types of port configuration:
  • Untagged. In this case, you set the VLAN on the port as a whole, and the switch will silently route only traffic on that VLAN to that port, and tag the traffic appropriately going out other ports on that VLAN. This is what you'd do if you plugged a printer or PC into the port. The port only passes traffic on its assigned VLAN.
  • Trunk/Tagged. All traffic is tagged with a VLAN. Usually you use this to plug into another managed switch. The port will pass all traffic on the VLANs it is assigned to, and it will tag the traffic appropriately.
  • Mixture. In this scenario, you set the PVID (primary VLAN ID) on the port. Untagged traffic going through that port is considered to be on the PVID, but the port will also pass tagged traffic for VLANs it is a part of.
An easy way to conceptualize it is to remember that the device connected to a given switch port must mirror the settings on that switch port.

Note that just having the different VLANs doesn't really help you if you don't have a way to route between them. If your router supports VLAN tagging, then you can set up the different networks in the router and it will route between them for you. If it doesn't, then you need to see if your switch is an OSI Level 2 or Level 3 switch. A L3 switch can route between the VLANs for you, while a L2 switch can't.

If you need a router that can handle it, I recommend the Ubiquiti EdgeRouter X - it's $49 and can handle gigabit speeds. There is a significant learning curve to it, though. Mikrotik also makes similar routers in this price range.

Netgear and TP_Link make very affordable VLAN-aware switches as well. You can get a 5 port one for about $35 and an 8 port for not much more.
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Old Jul 25, 18, 1:02 pm
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Here's how I have a Netgear 8 port switch configured at home.
  • Port 1 plugs into my router and passes untagged traffic on the main VLAN (I know I said you shouldn't use 1, but 1's traffic is always untagged in this case so it doesn't matter) and tags traffic on VLAN 10.
  • Port 2 plugs into a Samsung SmartThings base and is only an untagged member of VLAN 10, my guest network. It is excluded from the main network.
  • Ports 3-8 pass untagged traffic on the main VLAN and are excluded from the guest network.



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Old Jul 25, 18, 1:03 pm
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Thanks Dave.

Yes, it's a Level 3 switch, and I have no intention of using tagged traffic if I can help it.

My problem right now is getting past the password left over and finding its' Ip address, before I can even think of messing with the configuration.

I've located a couple of books that may shed some more light on what I'm trying to do, so off to the library and order them.

I'm kind of assuming once I get the hang of it, it should be pretty straightforward to maintain and change the configuration, but right now the initial steps are the stumbling blocks.
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Old Jul 25, 18, 1:06 pm
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Another (possible) issue - Nortel was bought out by Avaya a couple of years ago, and the chatter seems to indicate they won't even let me have the Java code to access the web GUI unless I sign a maintenance contract. Not gonna happen.
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Old Jul 25, 18, 1:11 pm
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It's all command line. There's no web UI. You need to connect to the management serial port. Page 25 of the installation manual: https://downloads.avaya.com/css/P8/documents/100097603

Then you can set the switch's IP address. As the manual says, VLAN 1 is default reserved as the management VLAN (the one from which you can access the switch's management interface).

This is a real managed switch, not a web-based "managed" switch like my Netgear.

Here's the operating manual, in case you hadn't gotten it. https://downloads.avaya.com/css/P8/documents/100097604
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Old Jul 25, 18, 2:15 pm
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Originally Posted by gfunkdave View Post
It's all command line. There's no web UI. You need to connect to the management serial port. Page 25 of the installation manual: https://downloads.avaya.com/css/P8/documents/100097603
Great! Love the command line!
Originally Posted by gfunkdave View Post
This is a real managed switch, not a web-based "managed" switch like my Netgear.
That's a good thing, right?
Originally Posted by gfunkdave View Post
Here's the operating manual, in case you hadn't gotten it. https://downloads.avaya.com/css/P8/documents/100097604
Thanks for the links - a bit of reading and "knowledging up" in my immediate future.

Gotta love FT - SOAK.
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Old Jul 25, 18, 2:56 pm
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Originally Posted by BigLar View Post
Great! Love the command line!
That's a good thing, right?
Sure. More powerful but a steeper learning curve and probably overkill for your needs.
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Old Jul 26, 18, 10:18 am
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There used to be some good tutorials for SMB usage (easier entry and good use cases) on the nortel forums (then they became a sub in the Avaya forums.

Here's my real recommendation though.

If you want to move in the direction of managed switching in your home.office LAN get a better switch with some support in place. With this older and unsupported switch you're exposing it potentially to holes in the code that should have been patched in the interim.

you can get really nice used 24 port managed switches from Dell (power connect) Cisco and in the more SMB space from Netgear (as gfunkdave has posted above) for 50$. There are many options to get updates without going the route of the full S&M contracts or fees and they run pretty bulletproof. I will always change out Fans though (if you get POE models or some older models) to slightly lower throughput but significantly lower noise) so they can be put in a home office or room and not make any noticeable sound other than some slight white noise. If you don't need/want POE you can get finless that won't make any noise and still be managed.
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Old Jul 26, 18, 12:57 pm
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Originally Posted by nmenaker View Post
you can get really nice used 24 port managed switches from Dell (power connect) Cisco and in the more SMB space from Netgear (as gfunkdave has posted above) for 50$.
Although most of my friends would describe me as "cheap", I prefer "frugal".

Just to be clear: this is not a mission-critical application. There are not millions of dollars and thousands of lives hanging on a successful outcome. My existing setup works fine. My only purposes in going this route are:

1. Curiosity - I like to play with hardware.
2. Opportunity - getting the device for less than the cost of a six-pack
3. A vague desire to neaten up the office.
4. Maybe pick up some skills that are saleable.

If it doesn't work, well, I'm only out the ten bucks and I can easily go back to my original configuration.

I recall one time I asked about getting an adapter to put a Holley double-pumper on a Chevy 327. Several well-meaning folks suggested I get a Bimmer or the like as they were better cars. True, but misses the point of the post entirely. An all-too-common misconnect on many IBB's. <shrug>
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Old Jul 27, 18, 6:38 am
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Well, a couple of 300+ page manuals later, I'm actually making progress!

Fired up hyperterminal (I keep an old laptop running XP for just this sort of thing) and got into the console interface. No problem setting up the desired VLANs, but there is so much other stuff that has to be right, I think it's gonna take some more experimenting (a.k.a. "playing around") to get it right.

Fortunately, geek stuff like that is my catnip. 2 AM with stuff strewn all over the desk, manuals open, fans whirring, and bad words coming out of my mouth - that's what makes life worth living!

Mucho thanks for the links, Dave. I'm in nerdvana.
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Old Jul 27, 18, 11:17 am
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WinXP and Hyperterminal? Can you hear me over there in 2003?

Use PuTTY like everyone else. https://www.chiark.greenend.org.uk/~...ty/latest.html

Just make sure that each port on your switch is set to provide untagged traffic to end devices (PCs, printers) and that any tagged traffic is going out a port that is connected to something that expects tagged traffic.
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Old Jul 27, 18, 11:30 pm
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Originally Posted by gfunkdave View Post
WinXP and Hyperterminal? Can you hear me over there in 2003?

Use PuTTY like everyone else. https://www.chiark.greenend.org.uk/~...ty/latest.html

Just make sure that each port on your switch is set to provide untagged traffic to end devices (PCs, printers) and that any tagged traffic is going out a port that is connected to something that expects tagged traffic.
Yeah, yeah, yeah. I haven't used PuTTY in a couple of years - haven't needed to. I believe I downloaded it a while back, but without an immediate use for it, the knowledge just sort of seeps away.

Hyperterminal came with XP - not available on Win7. Doesn't matter - I just had to get into the console and since I don't have a VT-100 laying around, it worked.

The switch is now configured to my liking and tested. Next step is to put it in place, remove the other switches, and try to neatly dress the wires.

Fat City, kiddo, and I owe a lot of it to you. Muchas gracias!!
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