2 POE switches

[Monka]

Good day every one,

I just want to find out if it is possible to connect from one POE switch to another without any intermittent connectivity on the VOIP phones.

There is a client who has applied for business fibre and has 1meg of the bandwidth allocated to the VOIP and i want to know that if i need to connect all the phones to 1 switch and the PC'S to another or can every I run everything on one switch and the switch will route the traffic?

 

[bdt]

Good day every one,

I just want to find out if it is possible to connect from one POE switch to another without any intermittent connectivity on the VOIP phones.

There is a client who has applied for business fibre and has 1meg of the bandwidth allocated to the VOIP and i want to know that if i need to connect all the phones to 1 switch and the PC'S to another or can every I run everything on one switch and the switch will route the traffic?

Sure, knock yourself out (the equipment will be fine).

Longer answer: assuming (and no reason not to) standard, and more than likely 802.3af switches and phones, power gets activated only after a successful handshake between a source device (the switch), and a client - in this case a phone. The two switches connected to each other will not handshake for power delivery but will quite happily pass network packets being as that's what switches do. So jack all the phones into the one switch - say, for the sake of neatness*, and the PCs into the other.

* only do that for another reason too: VoIP traffic is in the kB/s range, and your switches are at the very least 100MB/s capable so, even at max chat, all the phones going will amount to a functionally trivial amount of traffic on that one port of the upstream switch, and its remaining ports would then service PC traffic.

Also, simplifying somewhat, switches don't route traffic, that's what routers do - it's in the names. And pay attention to setting up the router to get your VoIP traffic prioritised because your bottleneck potential is on the WAN side, not the LAN.

 

[SauRoNZA]

Good day every one,

I just want to find out if it is possible to connect from one POE switch to another without any intermittent connectivity on the VOIP phones.

There is a client who has applied for business fibre and has 1meg of the bandwidth allocated to the VOIP and i want to know that if i need to connect all the phones to 1 switch and the PC'S to another or can every I run everything on one switch and the switch will route the traffic?

There is no routing on a LAN as you are not passing a router.

You can run it all on one switch if you have enough ports for it or a couple of switches if you need to expand.

Depending on how many ports you need just for simplicity of management it’s usually a good idea to generally put devices of a similar type in the same block of ports.

Assuming this is a small Business in a perfect world you would want a second switch and separate it so that you have at least as many ports free as you have in use so that should one switch fail you can move all your stuff across with minimal down time.

 

[Monka]

Sure, knock yourself out (the equipment will be fine).

Longer answer: assuming (and no reason not to) standard, and more than likely 802.3af switches and phones, power gets activated only after a successful handshake between a source device (the switch), and a client - in this case a phone. The two switches connected to each other will not handshake for power delivery but will quite happily pass network packets being as that's what switches do. So jack all the phones into the one switch - say, for the sake of neatness*, and the PCs into the other.

* only do that for another reason too: VoIP traffic is in the kB/s range, and your switches are at the very least 100MB/s capable so, even at max chat, all the phones going will amount to a functionally trivial amount of traffic on that one port of the upstream switch, and its remaining ports would then service PC traffic.

Also, simplifying somewhat, switches don't route traffic, that's what routers do - it's in the names. And pay attention to setting up the router to get your VoIP traffic prioritised because your bottleneck potential is on the WAN side, not the LAN.

Mmmm ok well said, actually the I want to deploy two switches it's because the client a 2 storey building/warehouse and i am trying to avoid running too many cables from one floor to another, as the only way we can route the cabling is outside inside trunking but client had his share of fun with those cables being fried every time there is light.

 

[SauRoNZA]

Are you doing to use a separate router for this 1MB dedicated to VOIP?

Then you’ll need to plan carefully with either multiple switches for simplicity, or managed switch where specific ports only talk to each other on the same physically separate network or a VLAN setup.

 

[Monka]

Are you doing to use a separate router for this 1MB dedicated to VOIP?

Then you’ll need to plan carefully with either multiple switches for simplicity, or managed switch where specific ports only talk to each other on the same physically separate network or a VLAN setup.

Reason for deploying two switches is just for futur purposes as the area is very bad with lightning and i just wanted to minimize the cost of replacing cables with only one length of cable and with regards to the 1MB decicated voip I wanted to know if I should run separate network points for phones and another for PC'S in order to ensure the 1MB will be used on the VOIP as the current setup up there is only one point that connects to the phone and from the phone to PC

 

[SauRoNZA]

Reason for deploying two switches is just for futur purposes as the area is very bad with lightning and i just wanted to minimize the cost of replacing cables with only one length of cable and with regards to the 1MB decicated voip I wanted to know if I should run separate network points for phones and another for PC'S in order to ensure the 1MB will be used on the VOIP as the current setup up there is only one point that connects to the phone and from the phone to PC

Will all depend on exactly how this 1MB is being provided to the VOIP system.

Presumably the VOIP gateway is talking directly to it and the VOIP clients are on the same LAN simply pointing to that gateway.

If it’s a separate setup with its own DHCP server or there is UTM splitting and managing traffic or some such or might get more complicated.

But good idea to run two cables between the switches maybe along different paths if you can.

 

[Monka]

Will all depend on exactly how this 1MB is being provided to the VOIP system.

Presumably the VOIP gateway is talking directly to it and the VOIP clients are on the same LAN simply pointing to that gateway.

If it’s a separate setup with its own DHCP server or there is UTM splitting and managing traffic or some such or might get more complicated.

But good idea to run two cables between the switches maybe along different paths if you can.

Noted with thanks for the information

 

[websquadza]

But good idea to run two cables between the switches maybe along different paths if you can

Be careful with this. This is when we, as ISPs, get that call that says “our internet is broken“.

If you run two cables between two switches, you will get a loop. simple as that. Now in you implement LACP/Port Grouping, you will have 2 links acting as one- but you need to configure this properly. And don’t go near STP (before my fellow network guys say I’m crazy- please show me one campus STP solution that hasn’t given you a headache). STP goes on the fritz and you’re left hunting “bad call quality.”

Yes, you can run as many switches in series as you like (remember, a break in the series affects all subsequent switches). But you’re running two, so you’re fine. If you can- order a preterminated fibre and run that between the switches (assuming they have SFP ports). This helps make sure your lightning problem doesn’t take out both switches at once.

Run a VLAN for voice. It’s easy and lets you manage your voice traffic and eliminate broadcast issues. Don’t use your switch’s built in voip Vlan tool- they usually don’t work. Just tag every port (lag included) on the switches with a Vlan (eg. 10) and configure the phones to use the same. Make sure the separate VoIP gateway is configured on an access port or can use VLANS.

 

[SauRoNZA]

Be careful with this. This is when we, as ISPs, get that call that says “our internet is broken“.

If you run two cables between two switches, you will get a loop. simple as that. Now in you implement LACP/Port Grouping, you will have 2 links acting as one- but you need to configure this properly. And don’t go near STP (before my fellow network guys say I’m crazy- please show me one campus STP solution that hasn’t given you a headache). STP goes on the fritz and you’re left hunting “bad call quality.”

Yes, you can run as many switches in series as you like (remember, a break in the series affects all subsequent switches). But you’re running two, so you’re fine. If you can- order a preterminated fibre and run that between the switches (assuming they have SFP ports). This helps make sure your lightning problem doesn’t take out both switches at once.

Run a VLAN for voice. It’s easy and lets you manage your voice traffic and eliminate broadcast issues. Don’t use your switch’s built in voip Vlan tool- they usually don’t work. Just tag every port (lag included) on the switches with a Vlan (eg. 10) and configure the phones to use the same. Make sure the separate VoIP gateway is configured on an access port or can use VLANS.

Very good warning.

I meant run the cables and have them in place not actually have them both connected, but probably should have made that clearer.

As you rightly say HA is a special configuration and also requires the correct hardware to make it happen and work correctly, which is unlikely in this case.

 

[Monka]

Be careful with this. This is when we, as ISPs, get that call that says “our internet is broken“.

If you run two cables between two switches, you will get a loop. simple as that. Now in you implement LACP/Port Grouping, you will have 2 links acting as one- but you need to configure this properly. And don’t go near STP (before my fellow network guys say I’m crazy- please show me one campus STP solution that hasn’t given you a headache). STP goes on the fritz and you’re left hunting “bad call quality.”

Yes, you can run as many switches in series as you like (remember, a break in the series affects all subsequent switches). But you’re running two, so you’re fine. If you can- order a preterminated fibre and run that between the switches (assuming they have SFP ports). This helps make sure your lightning problem doesn’t take out both switches at once.

Run a VLAN for voice. It’s easy and lets you manage your voice traffic and eliminate broadcast issues. Don’t use your switch’s built in voip Vlan tool- they usually don’t work. Just tag every port (lag included) on the switches with a Vlan (eg. 10) and configure the phones to use the same. Make sure the separate VoIP gateway is configured on an access port or can use VLANS.

ADDITION:Just to add the router is sitting downstairs and the cable going upstairs was to uplink the switch upstairs and there are clients connected downstairs and others are upstairs

 

[Monka]

Very good warning.

I meant run the cables and have them in place not actually have them both connected, but probably should have made that clearer.

As you rightly say HA is a special configuration and also requires the correct hardware to make it happen and work correctly, which is unlikely in this case.

Yep, I had to squeeze the client to get them to switch over to POE

 

[syntax]

Be careful with this. This is when we, as ISPs, get that call that says “our internet is broken“.

If you run two cables between two switches, you will get a loop. simple as that. Now in you implement LACP/Port Grouping, you will have 2 links acting as one- but you need to configure this properly. And don’t go near STP (before my fellow network guys say I’m crazy- please show me one campus STP solution that hasn’t given you a headache). STP goes on the fritz and you’re left hunting “bad call quality.”

Yes, you can run as many switches in series as you like (remember, a break in the series affects all subsequent switches). But you’re running two, so you’re fine. If you can- order a preterminated fibre and run that between the switches (assuming they have SFP ports). This helps make sure your lightning problem doesn’t take out both switches at once.

Run a VLAN for voice. It’s easy and lets you manage your voice traffic and eliminate broadcast issues. Don’t use your switch’s built in voip Vlan tool- they usually don’t work. Just tag every port (lag included) on the switches with a Vlan (eg. 10) and configure the phones to use the same. Make sure the separate VoIP gateway is configured on an access port or can use VLANS.

I've had issues with STP, but I've also had issues with BGP, OSPF, MPLS, LDP, Link aggregation and the list goes on.
Just because you have had an issue with something does not mean you should disregard it.
Other alternatives can bring their own challenges and in some cases require higher end switches.
Link aggregation works in this scenario and I would agree STP is not necessary here, adding a 3rd switch would probably require it.

What I am interested in is how the voice is going to be split once it reaches the router unless all they have purchased is just a voice service.

With regards to cabling, its fairly common to run just a single cable that goes to the phone which then goes to the PC. Configure the ports with voice and access VLANs if the switch supports this. Adding QoS is probably a good idea and might help for traffic prioritization and identification of that traffic when you hit the router.

 

[Monka]

Last paragh give me a piece of mind and what would be your take with regards to up linking one switch with another.

 

[syntax]

If you are just connecting 2 switches then the suggestion of link aggregation is a good one.