Question 16-Port Switch Only Allows 7 Connections

[ajaz1986]

Hi Guys

I will try to list as much information as possible about my network setup and the problem I am facing.

Devices:
Modem/Router/Hub = Virgin Media Hub 3.0 w/100Mb fibre connection
Switch = TP-Link SF1016D (16-Port Switch)
Wireless Repeater = TP-Link TL-WA860RE
Wireless Repeater = TP-Link RE305
Wired Devices = 2 Connected to Hub + 8 Connected to Switch
Wireless Devices = 11 Connected To Hub (including the 2 repeaters)

Setup Description:
My modem/hub is in my living room and I've setup a little workshop in my shed at the back of the garden. My workshop devices are not wireless compatible and so, I purchased a wireless repeater with an RJ45 wired connector slot but the signal was weak, so I purchased a second wireless repeater to sit in my kitchen (which is between the living room and my shed). So, the repeater is setup to extend the signal of the Hub from the living room and using the second repeater in the shed, I can now catch a good signal. I have an ethernet cable going from the second repeater (in the shed) to a switch mounted on the shed wall.

The switch is 16-port and I was occupying 6 ports for my machines with no issues (just reboot the switch each time you connect a new device), plus the connection from the repeater to the switch, so effectively, I was occupying 7 ports with no issues.

The Problem:
I added another machine to my shed and occupied an 8th port and it worked fine but at that time, another machine was offline for several weeks because of upgrades so I didn't think anything of it. Now I've switched 8th machine back on, it's not connected to the internet. I've troubled shooted by swapping ethernet cables, swapping OS images, swapping hardware and buying a USB-NIC but still no joy and I thought. I pulled another device out from the switch and behold, the 8th device came online!

I've tried it a few times to confirm and basically, although it is a 16-port switch, it is only allowing 7 connections to go online at any one time.

Please, can someone assist me with this problem?

I have attached a quick sketch of my layout so you can visualise it. I hope it helps.

 

[bill001g]

That must run slow with 8 devices behind a single wifi connection.

Its hard to say but I know it is not the switch causing it. These devices are really stupid, they pretty much just keep a table of what mac address they see on what port. The table can contain 1000 entries on that switch. That means you could connect a total of 1000 devices by hooking up many switches or other methods. It can also run all ports at full speed up and down all simultaneously. for a total bandwidth of 3.2gbit. Not a huge accomplishment since gigabit switches can pass 2gbit/port.

My guess would be it is a limitation in the repeater. Repeaters use a function called WDS to allow multiple mac address to pass over a encrypted wifi connection. This is because the mac address normally is part of the encryption keys and you can't have multiple keys. In any case WDS is not part of the official standard and companies pretty much implemented it any way they wanted. It has been around so long it is mostly compatible between brands but there maybe setting or restrictions on the number of mac addresses in this particular implementation.

I would check the setting on both your repeater devices and see if there is a setting or a documented limitation.

I know if you used a point to point bridge system like the ubiquti nanosttion loco ac devices I have seen people claim to have over 100 devices running over it. Likely not real fast but this is closer to commercial equipment. They are not expensive a pair is just over $100.

 

[jsmithepa]

That is totally odd, re-check your DHCP lease range.

 

[ajaz1986]

That must run slow with 8 devices behind a single wifi connection.

Its hard to say but I know it is not the switch causing it. These devices are really stupid, they pretty much just keep a table of what mac address they see on what port. The table can contain 1000 entries on that switch. That means you could connect a total of 1000 devices by hooking up many switches or other methods. It can also run all ports at full speed up and down all simultaneously. for a total bandwidth of 3.2gbit. Not a huge accomplishment since gigabit switches can pass 2gbit/port.

My guess would be it is a limitation in the repeater. Repeaters use a function called WDS to allow multiple mac address to pass over a encrypted wifi connection. This is because the mac address normally is part of the encryption keys and you can't have multiple keys. In any case WDS is not part of the official standard and companies pretty much implemented it any way they wanted. It has been around so long it is mostly compatible between brands but there maybe setting or restrictions on the number of mac addresses in this particular implementation.

I would check the setting on both your repeater devices and see if there is a setting or a documented limitation.

I know if you used a point to point bridge system like the ubiquti nanosttion loco ac devices I have seen people claim to have over 100 devices running over it. Likely not real fast but this is closer to commercial equipment. They are not expensive a pair is just over $100.

Hi Bill

Thanks for the reply,

After posting, I found a lot of posts online about the Virgin Media Super Hub 3.0 (SH3) which is what I've got and how it struggles when running 12+ connections simultaneously, so I was starting to think maybe that's the issue?

Sorry, I'm not as tech-savvy as I would like to be... I have logged into the repeaters admin panels but I can't see anything obvious that would be limiting the connections. However, not sure if this is something to look into but it is showing 8 devices in my shed (1 switch + 7 machines) as being connected by wireless even though it's all wired up.

 

[ajaz1986]

That is totally odd, re-check your DHCP lease range.

Sorry, I got no idea how to do that. I'm using an Apple Macbook Pro so I have Terminal. Do you know how I could check through that? I've found instructions online but it's only about renewing the lease for the machine I'm using, which I don't think is what you're saying.

 

[jsmithepa]

Somewhere in your network, there is a DHCP server, this is usually next to the modem, or the modem itself if it's one of those all-in-one boxes, AND THERE SHOULD ONLY BE ONE, very important. This DHCP server job is to lease out IP addresses to every device you plug into the network. Whoever set this up could have potentially only allowed a limited number of IP addresses to be used, intentional or not.

Your diagram shows no hardware firewall, but I used to have a semi-pro SonicWall firewall that limited my LAN devices to ~10 'cuz that was what was purchased with the license.

 

[ajaz1986]

Somewhere in your network, there is a DHCP server, this is usually next to the modem, or the modem itself if it's one of those all-in-one boxes, AND THERE SHOULD ONLY BE ONE, very important. This DHCP server job is to lease out IP addresses to every device you plug into the network. Whoever set this up could have potentially only allowed a limited number of IP addresses to be used, intentional or not.

Your diagram shows no hardware firewall, but I used to have a semi-pro SonicWall firewall that limited my LAN devices to ~10 'cuz that was what was purchased with the license.

Yeah, the DHCP is managed by the Super Hub 3.0 which is a modem/router in one. When I go to DHCP section of the admin panel I see 'Number of CPEs = 245' I believe that is the limit right?

 

[jsmithepa]

I see 'Number of CPEs = 245' I believe that is the limit right?

If u can post a screen shot I will confirm it for you.

U should also be aware of statics IP used. Some recent poster didn't know one has to exclude static IP used from the lease range, and that certainly will confuse the network possibly preventing you from plug in more devices.

 

[ajaz1986]

If u can post a screen shot I will confirm it for you.

U should also be aware of statics IP used. Some recent poster didn't know one has to exclude static IP used from the lease range, and that certainly will confuse the network possibly preventing you from plug in more devices.

See screenshot. Scrolling down it then shows me a list of reserved IP's which does include the device + associated IP for the device which is currently offline.

 

[peters43gone]

Hi Guys

I will try to list as much information as possible about my network setup and the problem I am facing.

Devices:
Modem/Router/Hub = Virgin Media Hub 3.0 w/100Mb fibre connection
Switch = TP-Link SF1016D (16-Port Switch)
Wireless Repeater = TP-Link TL-WA860RE
Wireless Repeater = TP-Link RE305
Wired Devices = 2 Connected to Hub + 8 Connected to Switch
Wireless Devices = 11 Connected To Hub (including the 2 repeaters)

Setup Description:
My modem/hub is in my living room and I've setup a little workshop in my shed at the back of the garden. My workshop devices are not wireless compatible and so, I purchased a wireless repeater with an RJ45 wired connector slot but the signal was weak, so I purchased a second wireless repeater to sit in my kitchen (which is between the living room and my shed). So, the repeater is setup to extend the signal of the Hub from the living room and using the second repeater in the shed, I can now catch a good signal. I have an ethernet cable going from the second repeater (in the shed) to a switch mounted on the shed wall.

The switch is 16-port and I was occupying 6 ports for my machines with no issues (just reboot the switch each time you connect a new device), plus the connection from the repeater to the switch, so effectively, I was occupying 7 ports with no issues.

The Problem:
I added another machine to my shed and occupied an 8th port and it worked fine but at that time, another machine was offline for several weeks because of upgrades so I didn't think anything of it. Now I've switched 8th machine back on, it's not connected to the internet. Destination net unreachable error can be fixed by visiting the link. I've troubled shooted by swapping ethernet cables, swapping OS images, swapping hardware and buying a USB-NIC but still no joy and I thought. For destination host error, click here. I pulled another device out from the switch and behold, the 8th device came online! I've tried it a few times to confirm and basically, although it is a 16-port switch, it is only allowing 7 connections to go online at any one time.

Please, can someone assist me with this problem?

I have attached a quick sketch of my layout so you can visualise it. I hope it helps.

In my first analysis, I think the nod distance(two wireless repeaters are used) between the Virgin Media Hub 3.0 w and your TP-Link SF1016D switch is seriously affecting the Internet sharing quality. But it is not sure yet, just a through only.

If I were in your position, I would ensure that the TP-Link SF1016D switch works properly with more than 8 devices. A difficult job but if you can connect the TP-Link SF1016D switch directly to the modem, you can check whether it supports more than 8 devices at a time with proper Internet sharing.

 

[jsmithepa]

DHCP reservation looks good. Screenshot doesn't show static reservations but at this point am going to take your word for it.

If u want to test whether WIFI repeaters are at fault, temporarily move switch to living room and attempt to hook up extra devices there.

 

[ajaz1986]

In my first analysis, I think the nod distance(two wireless repeaters are used) between the Virgin Media Hub 3.0 w and your TP-Link SF1016D switch is seriously affecting the Internet sharing quality. But it is not sure yet, just a through only.

If I were in your position, I would ensure that the TP-Link SF1016D switch works properly with more than 8 devices. A difficult job but if you can connect the TP-Link SF1016D switch directly to the modem, you can check whether it supports more than 8 devices at a time with proper Internet sharing.

Yes, the repeaters will significantly reduce the internet connection quality but the devices I'm connecting only require speeds of like 100~150kbps each. Not streaming nothing heavy, they are mining rigs and to be sure, I recorded the upload/download speeds when they were operating.

 

[ajaz1986]

DHCP reservation looks good. Screenshot doesn't show static reservations but at this point am going to take your word for it.

If u want to test whether WIFI repeaters are at fault, temporarily move switch to living room and attempt to hook up extra devices there.

I can't move the rigs (devices) from the shed, they are huge and in the house I only have 5 wired devices I can hook up to the switch.

Can anyone recommend a repeater that will allow 10+ devices to connect simultaneously? It would probably easier for me to simply replace mine than to try test them.

 

[bill001g]

I have had good luck with the ubiquiti nano loco. I have not used the newer AC ones but I suspect they work just as good as the older 802.11n ones. They have them priced the same so no sense buying the old models. About $100/pair.

Depends on the distance but you could just string a ethernet cable over the top of the ground just to test

 

[mark1776]

Another point I have seen problems similar to this is with the connection tracking functions in the NAT, which is necessary to map multiple local addresses to your single internet IP. The symptoms are that only a limited number of devices can get to the internet at one time, but internally, the network seems fine.

That is, the DHCP function is just fine, with all system getting their IP address from the DHCP server, but the NAT to the internet limits connectivity. I got rid of the TPLink router and replaced it with a linksys 1600AC, and the problem was solved. Most, but not all, devices used wired network connections to the switch/router.

If the problem is DHCP, then the internal network will not work as well as having a lack of internet connection.