QoS on VoIP (SIP Calls)

[SilviuBiden]

Hey!

I have a strange problem between 2 VLAN which are passing thru Checkpoint.

In VLAN1 I have a SIP Server. This is forwarding calls to Remote Access Agents and to another 2 SIP Servers located remotely via VPN site-to-site. Source of the calls is located on VLAN2. There is no problem for incoming calls. For outgoing calls, the connection is established, but the sound quality is very poor.

Flow of outgoing calls:

Agent (remote VPN to Checkpoint) -> SIP Server 1 (VLAN1) -> SIP Server 2(VLAN2) -> Provider 

For incoming calls, flow is follwoing the same way back.

No Qos in place, no bottlenecks, rules are ok...  no nothing but still I have this issue.

Can you help me please with some hints?

[Chris_Atkinson]

For context could you please share the model appliance used and the version & jumbo installed on the system?

Fragmentation or MTU issues via the VPN?