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SF300-24P VLAN Confusion - autosmartport not being too smart?

Hi Everyone, first question i've posted, i'll try and give as much information as possible, i'm an extremely quick learner as well and have been around networking for nearly 20 years but this is my first outing into the medium sized VoIP deployment with prioritised LAN traffic and a client that is itching to say "told you so" about using IP phones.

I have 4 x SF300-24P switches in a network i'm deploying, 1 will be adjacent to the router (a draytek Vigor 3200 - 4xWAN Gigabit) and the other 3 will be trunked using the GE/01-GE/03 ports to the main switch and will then distribute through a patch panel to give me 96 network ports with PoE capability where required.  There will be 30+ IP Phones on the network, all of which are Yealink T38G SIP handsets.

I want to have two VLAN's - one for regular workstations, and one for IP Phones with the IP Phone VLAN getting high prority for its traffic on the LAN - all documentation makes it sound simple but it doesn't seem to be working the way I think I expect it to.  I don't mind the two VLAN's sharing the same IP address space at this time and currently all occupy internally.

So, I have 2 questions and a problem.

First, from the factory, the switches are configured that VLAN1 is the default VLAN and that auto-voice VLAN is also VLAN1?  Is this right?

Second, i'm having trouble determining the difference in terminology for port types between general, access, trunk etc - obviously trunk is between switches and carries VLAN information through to the next segment of the network.

My main problem seems to be with auto-voice VLAN and smartport.  If I enable smartport, the switch figures out through LLDP that the port is used by an IP Phone + Desktop (excellent, this is what I want it to do) so then puts the handsets in VLAN1 but then the handsets start to become invisible on the network after 2-3 minutes, the handsets then reboot because they've detected a network drop out and then reconnect, re-register at the voice server and are visible and contactable for 2-3 minutes then the loop begins again.

If I disable smartport, the problem goes away.

Am I unreasonably expecting that any user can unpack an IP phone and (subject to provisioning on the server), plug it into any port on the network and it will figure out that it's a phone, not a PC and then prioritise its traffic?

What I want to avoid is the possibility of internal bandwidth lag if someone copies a large file over the network and people are using the phones that the phone users don't get packet loss or audio instability because of the file copy.  The internet side will be fine, the Vigor3200 has QoS facilities built in and i've had good success on smaller networks with these routers.

Ideally I need a semi-planned network setup where people with WiFi SIP clients will also get some priority.

I have set QoS on the handsets to match DSCP46 from the switches - can the traffic be manipulated this way or does it already do that in the DSCP to Queue setup which automatically puts anything above 40 in Queue 4 (high priority).

All help very greatfully received.


Everyone's tags (2)

SF300-24P VLAN Confusion - autosmartport not being too smart?

Hello James,

Welcome to the forums!

About the default settings. The switch comes with vlan1 as the default vlan for all traffic.

Here is a quick overview of the port settings

access - one vlan

trunk - multiple vlans

general - multiple vlans (had additional options)

When using the auto voice-vlan, you can have your port set as access for vlan 1 and when the switch see a phone connected, it will join the voice vlan also. This allow the ports to be dynamic. It is not necessary to do this. You can create all ports as trunk ports that are part of both your default vlan and your voice vlan.

The benifits of auto-voice vlan

-phones are discovered and joined to the vlan dynamically

-predetermined QoS settings

-security in that you can have your port set to access

This is a relatively basic overview.

As for the problem you are seeing. I would recommend that you check the firmware of the switch and upgrade if needed. While it may not have anything to do with the problem at hand, it will help prevent any future issues.

I would suggest disabling the Green Ethernet, which can be found under the port management section. If you continue to see the problem after that, I would recommend giving us a call at the support center. We will be able to look a little closer to what is happening.