IP Office VoIP phones Subnet and VLAN question

[ccctech]

I am about to try to link two IP500V2 systems together with VoIP Phones across a MPLS circuit
Site 1:
Data VLAN 1 for PC's using 10.1.1.x network and Voice VLAN100 using 10.1.100.x with both using subnet 255.255.0.0 and default gateway 10.1.1.1

Site 2:
Data VLAN 1 for PC's using 10.2.1.x network and Voice VLAN100 using 10.2.100.x with both using subnet 255.255.0.0 and default gateway 10.2.1.1

My question is; I realize each location has its own network domain, but each location's voice and data traffic is technically using the same broadcast domain, however the VoIP traffic will be on a separate VLAN will there be any voice quality issues? I have only set this scenario up before when both data and voice vlan's are on the different subnets and default gateways and works great. Also if this is acceptable, would the Ethernet Switch port connected to the router be setup as a Trunk to carry both VLAN 1 and 100 even though both VLAN's devices are using the same default gateway?

Thank you in advance for any guidance.

 

[madwok]

I don't see much advantage in this setting instead of using one native VLAN for both voice and data . The reasons that we would want VLAN are security, broadcast domain and ease of administration . I always think that each VLAN should be in its own subnet with a layer 3 device at the edge to control the broadcasting traffic.
If we have plenty of bandwidth and small # of IP sets & hots , voice quality is pretty decent in most case, at least within the LAN . In reality at the router/WAN side is where we usually have to deal with voice quality . MPLS might help in speed up some but if we don't have QOS/COS service from your LEC vendor , we still more likely would have voice quality issue as there is no control over congestion/priorization for site 2 site traffic.
There are lot of smart folks in this board , please chime in as I am still very novice at this QOS/COS black art.

 

[Albus2]

In this setup VLAN is not working as expected. Because all 10.1.x.x is in the same subnet. I.e. you cannot separate anything by putting it in VLAN 1 or 100.

Use a netmask of 255.255.255.0 and a routing device to handle traffic between VLAN's.

 

[TheodisButler]

Rule for VLANS is nothing goes on VLAN 1. The minute you start creating VLANS everything should get off of VLAN 1.

In regards to CoS/QoS, the subnet that your phones are on is irrelevant. What is important is the QoS settings in both IP offices at each site. I recommend using DiffServ instead of IntServ but it depends on what routers you have, what type of switches you have, and if your MPLS provider will tag your voice packets using what particular QoS specification (some support multiple).

Remember this number: 46

Theodis Butler
President

http://www.megalithtechnologies.com

 

[Bas1234]

46= Valentino Rossi

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