Issue:

In VOS-uCPE environment where the Riverbed is running as a VM and Versa-SDWAN in baremetal, there were issues where Versa is dropping data traffic in the service-chain interface connected to the Riverbed-VM. This is because the Riverbed-VM is not capable of receiving the traffic at higher rate from Versa. Since the Riverbed is not receiving the traffic at the rate Versa receives at the LAN side, Versa will drop the traffic.

Below is the issue where the drop counters will get incremented in case of such issues.

vsh connect vsmd

vsm-vcsn0> show vsm statistics dropped

 

DPDK ERROR STATISTICS

~~~~~~~~~~~~~~~~~~~~~

Interface/Port  : vni-0/303

# Failed transmitted packets               : 65384

 

 

Resolution:

To resolve this issue, we can enable multi-queue settings in the VOS-guest vnfs config before creating the VM. This will enable multiple queues in the data interfaces between VOS and the Riverbed-VM. Versa supports this multi-queue capability from 21.x onwards. Riverbed later versions also supports this capability. Once enable this multi-queue, VOS will configure the number of queues same as the number of CPU allocated to the Riverbed-VM. For ex., If 4 CPU is allocated to the Riverbed-VM then VOS will set the queue to 4 in the VNF.xml file in the /etc/libvirt/qemu path.

Please see the below screenshot from the Director-Configuration template page. Once the service-chain template is created through the workflows, user can go the configuration page for that template and enable this multi-queue settings. This will take care of adding the queue-settings in the xml file generated for each interface. Remember this configuration should be enabled before doing ZTP/pushing first time this service-chain template config to the device. Because once the xml file generated then only option is to modify it manually to enable the multi-queue. That is why this setting must be enabled before doing ZTP in the template.

 

Graphical user interface, application Description automatically generated

 

Please note that only the recent versions of Riverbed models support this multi-queue capability. Before enabling this setting in the VOS device, please ensure to use the latest Riverbed VM version.