I have a configuration on a Cisco C897VA-K9 router that has a built in DSL modem. It has a simple internet connection via VDSL. There is a VPN configured on the device, that connects back to our main office. In order to have a reliable QoS configuration, I have to make sure the WAN Link is not overutilized at any time. The VDSL2 link has asymetric speeds. I have 41'582 Kbit/s download and 7'719 Kbit/s upload. I have a script that reads the synchronized upload speed, takes 80% of the bandwidth and configured this on a service policy that is then applied to the Dialer interface.
policy-map QOS_OUT class class-default shape average 6175200 service-policy QOS_OUT_CHILD interface Dialer1 service-policy output QOS_OUT
So i can manage the upload well. Problem is the download. Best practice would be, to limit the output on the LAN interface to make sure, the WAN link is not overutilized. Problem here is, that there are two LAN interfaces that could draw bandwidth from the WAN. How do I do that?
policy-map QOS_OUT class class-default shape average 33265600 service-policy QOS_IN_CHILD interface Vlan5 description LAN Interface1 for VPN ip vrf forwarding VRFA ip address 172.16.1.1 255.255.255.0 service-policy output QOS_OUT end interface Vlan6 description LAN Interface2 for Internet ip vrf forwarding VRFB ip address 10.0.0.1 255.255.255.0 service-policy output QOS_OUT end
So in this configuration, both Vlan interfaces could take 33 Mbit/s, therefore overutilizing the WAN link. What i could do, is divide the bandwidth by two. Issue here is, if interface Vlan5 is not utilized, Vlan6 can only take 40% of the total WAN bandwidth. This is an ugly solution. Is there some other approach where I can solve this? I did not post the configuration of the child policies, as the question only concerns the bandwidth part.