One Voice VLAN and two data VLANs configuration issue

[Bodrul islam]

One Voice VLAN and two data VLANs issues

I've tried to minimize unnecessary details as much as possible, please see the details below:

VLANs info:

VOIP VLAN10; 172.25.3.0/24

Data VLAN1; 192.168.0.0/24 – Production network

Data VLAN101; 172.26.0.0/23 – new production Network

Current PBX configuration:

AVAYA PBX 500.

On switch port there is a trunk between the PBX interface LAN2, Voice VLAN10 as the member and Native VLAN is set as the Data VLAN1.

DHCP for the IP phones is on the PBX itself and DHCP options are defined as well.

The PBX is able to ping VLAN 10 and Data VLAN 1 without any issue.

Switch Configuration:

Switch is Juniper Ex4200 but the concept is same here if not please do correct me. 

Each ports on the switch are set as in “Access Mode” where Data VLAN1 and VOIP VLAN10 are included on the same port.

One of the port is configured as Trunk as mentioned above between the PBX and VLAN 10 for the voice is set as the member and VLAN Data1 is set as the trunk.

The above configuration works fine with the IP phones and there is no issue with it.

Issues

The problem arises when we assign the new ‘Production’ (VLAN101) rather than ‘data’ (VLAN1) on the switch port beside the Voice VLAN10 and plug the handset in it doesn’t seem to be able to talk to the IP Office at all. The issue I see is that here the phone doesn’t like any other Data VLANs other than Data VLAN1 beside the voice VLAN 10 on the switch port, this lead me to the trunk port that is setup between the PBX and the switch where Data VLAN1 is set as the Native VLAN to accept untagged traffic and therefore the native VLAN (Data VLAN1) needs to be changed to new Data VLAN 101 in order for the phone to work and this has worked when I have tested it but then the phones that are connected on the access port with data vlan 1 and vlan 10 will get disconnected.

Is there any configuration needs to be made on the switch and PBX to achieve the above?  Where one single voice vlan to work on regardless of what the data vlan is?

Please do let me know if you need further information.

Many thanks

[saif musa]

Budrul,

Could you upload switch configuration please, it will helps to identify your trunking issue.

Regards

[Bodrul islam]

Hi Saif,

The issue has been resolved by changing the trunk port between the PBX and the switch to an access port. After looking a the pcaps i can see the PBX is able receive the tag traffic 802.1q but upon its return it sends it as untagged which goes through the native vlan (data vlan1) and this way it is able to communicate with the phones. so in essence the pbx is rreceiving trtaffic as tagged from vlan 10 and retruning the traffic through vlan1 since the traffic is untagged it goes through the native vlan. this would have worked if the PBX had the capability to tag the traffic upon its leaving port through the trunk, since the PBX is expecting untagged traffic it should have set as an access port on the first place on the switch.

Bodrul