This article describes how to configure separate inter-switch trunks for Audio Video Bridging (AVB) traffic and Video traffic on NETGEAR fully managed (ProAV) switches. The article explains profile creation order, MTU requirements, VLAN participation, and Spanning Tree configuration that is necessary to allow AVB and jumbo-frame video traffic to operate simultaneously between switches.
This article applies to all NETGEAR fully managed (ProAV) switches, including the M4250 series, M4300 series, and M4350 series.
Before you configure separate AVB and Video trunks:
- Ensure that two NETGEAR fully managed (ProAV) switches are present in your network.
- Ensure that two physical ports are available on each switch for inter-switch connectivity
- Ensure that administrative access is secured to the device UI and CLI
- Disable Auto-LAG
- Disable Auto-Trunk
- Identify VLAN IDs for Video VLAN and AVB VLAN (dynamic VLAN 2)
Background
In some deployments, AVB and video traffic traverse the same pair of switches. AVB profiles require a 1500‑byte MTU on trunk ports, while many video transports rely on jumbo frames (typically an MTU of 9198). Because the switch applies MTU at the physical port level, a single trunk cannot meet both requirements reliably. Using separate physical trunks lets each link run with the correct MTU and maintains stable operation for both AVB and video traffic
MTU clarification (Layer 2 vs Layer 3)
The MTU limitation described in this article applies at Layer 2 (Ethernet frame size), not at the IP layer.
Unlike IP MTU, which can rely on fragmentation or MSS adjustment at Layer 3, Layer-2 MTU does not support fragmentation. Ethernet frames larger than the configured Layer-2 MTU cannot be fragmented and are not guaranteed to be forwarded deterministically.
Depending on hardware behavior, buffering, and traffic conditions, oversized frames might drop, be forwarded intermittently, and introduce buffering and timing instability.
In mixed AVB and jumbo‑frame environments, non‑deterministic forwarding can disrupt AVB traffic, which depends on predictable delivery and tight latency bounds. To maintain reliable operation, route AVB and jumbo‑frame video traffic over separate physical trunks.
To configure separate trunks for AVB and Video VLANs:
1. Connect the AVB trunk.
Connect the two switches together using one cable on the ports that you want to use for the AVB trunk.
2. In the AV UI or the Engage Controller, create the Video and AVB profiles.
a. Create the Video profile on both switches
b. Create the AVB profile.
Note: Create the AVB profile last. If the AVB profile is created first, MVRP might cause issues when you create additional VLANs.
3. Confirm Auto-LAG and Auto-Trunk are disabled
a. Confirm that Auto-LAG has is disabled by the AVB profile.
b. Manually disable Auto-Trunk on both switches.
4. Configure the Video uplink ports
Configure the ports used for the Video uplink as one of the following:
- Access ports in the Video VLAN
- Tagged ports for the Video VLAN
5. Confirm that the MTU of the ports is set to 9198.
Go to Port Configuration, scroll to the right, beside the port that you are going to use for the Video VLAN, and set the frame size to 9198.
Note: The MTU configured on switch ports is a Layer-2 MTU. Frames exceeding this size cannot be fragmented and are not guaranteed to be forwarded reliably.
6. Configure the AVB uplink ports
a. Configure the ports used for the AVB uplink as tagged members of the AVB VLAN
b. The dynamic VLAN 2 is added automatically.
c. Confirm that the MTU of the ports is set to 1500.
Go to Port Configuration, scroll to the right, besides the port that you are going to use for the AVB VLAN, and Frame Size should be set to 1500.
Note: AVB requires an MTU of 1500 bytes at Layer 2 and assumes predictable, low-latency forwarding. Jumbo-frame traffic must not traverse AVB uplink ports.
7. Exclude the Video VLAN from the AVB uplink ports.
To exclude the Video VLAN, we have to use the command-line interface to manually exclude the Video VLAN from the AVB uplink ports.
a. Enter enable and configuration mode:
(Netgear Switch)> enable
(Netgear Switch)# configure
b. Apply the following commands:
(config)# interface 0/5
(interface)# vlan participation exclude 10
Note: In this example, we use interface 5, adjust according to your requirements
Note: In this example, we use VLAN10, replace with the VLAN ID of the Video VLAN.
c. Exit configuration mode and save the configuration.
(interface)# end
# save
8. Configure Spanning Tree Protocol.
On both switches:
a. Login into the device UI, and go to Switching > STP > Basic > STP Configuration.
b. Set Protocol Version to RPVST. The default setting is IEEE 802.1w.
9. Connect the Video trunk, by connecting the second cable between the switches using the ports configured for the Video uplink.
10. Verify STP port roles:
a. In the device UI, go to Switching > STP > Advanced > PVST Interface.
b. Select the VLAN IDs from the drop-down list.
c. Verify that the STP port roles for the uplink ports are correct, you should see Forwarding and Root on the port that is setup for the VLANs.
Conclusion
Using separate physical trunks for AVB and Video VLANs allows AVB traffic to operate with the required MTU of 1500 bytes while enabling video traffic to use jumbo frames.
Because Layer-2 MTU does not support fragmentation and forwarding behavior becomes non-deterministic when exceeded, separate trunks are necessary to ensure predictable latency, stable timing, and reliable operation for both AVB and video traffic in mixed ProAV deployments.