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Cisco L3 switches 4506, 3560 - Panasonic VOIP - help needed in QoS


Hello Guys,


I am having infrastructure with these switches and I configure all VOIP phones in voice vlans and its working.


Can anybody instruct me how to do QoS for my VOIP phones.




1 Accepted Solution

Accepted Solutions



have a look at the thread below, it lists various options for QoS on IPSec VPN tunnels on the Fortigate...

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9 Replies 9



QoS is a huge serious topic.

You need to understand what you want to achieve.


You need to gather the info from your VoiP kit vendor
like what DSCP or COS values are they going to use for signalling and RTP.


How much is the Voip predicted to use.
How much of your banndwidth are you willing to give to you Voip traffic.


You then need to set your network up using the guideline in this document

Each model of switch configures differenty so make sure you use the right model templates


Also as this is not a CIsco VOIP vendor solution I would stay away from AUTO-QOS as it is geared to an all Cisco solution.


Hope this helps


Regards, Alex. Please rate useful posts.

Hello Alex,

Thanks alot for your reply.


My company has office1 where Our Panasonic PBX box is sitting and we buy another office2 and it is connected to office1 by site to site VPN tunnel.


Office 2 have 6504 core and all remaining 4506 series. 4506 switches are connected with 10 gigabit SFP uplinks towards 6504.  So far I just Hard reset everything and everything is in default vlan.


thats why I get some times choppy voice on some phones.


I already plan to segregate vlans for VOIP and PCs.


Why we need to know the DSCP , COS values from vendor we just have to prioritize VOIP traffic towards the PBX box.


The regular users have no issues but service people who are always on phones have a lot issues.  I even try hooking that phones on new switch which is directly connected to Firewall but it doesn't help. We have 1gbps Internet connection.


I have no idea how much VOIP use bandwidth, I will go with standard numbers. I can give any bandwidth because we can tolerate bit slow internet but we need optimized VOIP.






do you have Panasonic phones (KX-HDV) ?

Just for my understanding, do the voice issues occur  when communicating between the two offices, that is, when voice traffic goes over the VPN ? We need to find out first if you are experiencing congestion, or if it might simply be an MTU issue. Can you post the configs of both sides ? And also the output of 'show interfaces x' where x is the physical outgoing interface on both sides ?

Hello George,


yeah, it never happen internally, and even i connect only one phone with new gigabit switch and connect straight to firewall and it still happens with that phone too.


we have separate tunnel for VOIP and general traffic.


So that means congestion is happening on site to site VPN firewalls ? 


How to verify the congestion on Firewalls?


How to Find an MTU issue ?


Do you need configs of Firewalls or Switches where phone is connected



". . .we can tolerate bit slow internet but we need optimized VOIP."

Is your VPN, that's carrying VoIP, sharing a link for general Internet access? If so, you really want to avoid doing that.

 Hello Joseph,


We are using Fortigate 100 D firewalls and we have separate tunnel for VOIP and general traffic.


Whats the optimize way to make it work perfect?



Across VPN, insure you don't overrun available bandwidth. You also insure VoIP bearer traffic goes first.

For example, if HQ had 100 Mbps bandwidth, but branches only had 10 Mbps, you would insure each branch was shaped for 10 Mbps, with VoIP bearer prioritized.

Conversely, if you had as above, but with 20 branches, you would might need to shape each branch such that all of them together, i.e. their aggregate, does not exceed 100 Mbps (e.g. shape each for 5 Mbps). Again, VoIP bearer prioritized.

Understand the Internet, itself, won't provide priority for your VoIP traffic, but generally the bottlenecks are your connections to the Internet. You manage them correctly, and often VoIP will work fine.

I assume the Fortigates are the tunnel endpoints ?



have a look at the thread below, it lists various options for QoS on IPSec VPN tunnels on the Fortigate...

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