Fritz!Box 7390 and QoS Tagging

Forums › 2degrees (including Slingshot, Orcon, Flip, Stuff Fibre, MyRepublic, 2talk and Vocus) › Fritz!Box 7390 and QoS Tagging

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Paul1977

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#1492410 15-Feb-2016 08:57

fe31nz:

I now have my EdgeRouter Lite sending my VOIP packets with VLAN PRI set to 5, which seems to be what Chorus want for traffic to use the committed bandwidth and have priority over other traffic on the fibre. This is the command I had to add to my config:

set interfaces ethernet eth0 vif 10 egress-qos "1:5 2:5 3:5 4:5 5:5 6:5 7:5"

It seems like that command will make all packets with a non-zero DSCP value have a VLAN PRI of 5, but I am still not sure how the settings work. I have no way of verifying that the packets are actually using my CIR bandwidth either - I will only find out when there is bad congestion happening sometime in the future.

I also noticed that the 2D/Snap VOIP packets I am receiving do not have the VLAN PRI field set. I really think they need to fix that, so that when everyone is on fibre, the VOIP traffic will have priority. They do have the DSCP field set - the SIP packets are set to CS3, and the RTP packets to EF.

Are you sure it shouldn't be:

set interfaces ethernet eth0 vif 10 pppoe 0 egress-qos "1:5 2:5 3:5 4:5 5:5 6:5 7:5"

Also, if the command is doing what you suggest, wouldn't this only work if all your VoIP traffic is already tagged with a value of 1-7?

Paul1977

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#1492412 15-Feb-2016 09:01

Paul1977:

fe31nz:

I now have my EdgeRouter Lite sending my VOIP packets with VLAN PRI set to 5, which seems to be what Chorus want for traffic to use the committed bandwidth and have priority over other traffic on the fibre. This is the command I had to add to my config:

set interfaces ethernet eth0 vif 10 egress-qos "1:5 2:5 3:5 4:5 5:5 6:5 7:5"

It seems like that command will make all packets with a non-zero DSCP value have a VLAN PRI of 5, but I am still not sure how the settings work. I have no way of verifying that the packets are actually using my CIR bandwidth either - I will only find out when there is bad congestion happening sometime in the future.

I also noticed that the 2D/Snap VOIP packets I am receiving do not have the VLAN PRI field set. I really think they need to fix that, so that when everyone is on fibre, the VOIP traffic will have priority. They do have the DSCP field set - the SIP packets are set to CS3, and the RTP packets to EF.

Are you sure it shouldn't be:

set interfaces ethernet eth0 vif 10 pppoe 0 egress-qos "1:5 2:5 3:5 4:5 5:5 6:5 7:5"

Also, if the command is doing what you suggest, wouldn't this only work if all your VoIP traffic is already tagged with a value of 1-7?

Oh wait, is this the EdgeRouter you have connected to the Internet, or the second one?

fe31nz

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#1492718 15-Feb-2016 16:18

Paul1977:

fe31nz:

I now have my EdgeRouter Lite sending my VOIP packets with VLAN PRI set to 5, which seems to be what Chorus want for traffic to use the committed bandwidth and have priority over other traffic on the fibre. This is the command I had to add to my config:

set interfaces ethernet eth0 vif 10 egress-qos "1:5 2:5 3:5 4:5 5:5 6:5 7:5"

It seems like that command will make all packets with a non-zero DSCP value have a VLAN PRI of 5, but I am still not sure how the settings work. I have no way of verifying that the packets are actually using my CIR bandwidth either - I will only find out when there is bad congestion happening sometime in the future.

I also noticed that the 2D/Snap VOIP packets I am receiving do not have the VLAN PRI field set. I really think they need to fix that, so that when everyone is on fibre, the VOIP traffic will have priority. They do have the DSCP field set - the SIP packets are set to CS3, and the RTP packets to EF.

Are you sure it shouldn't be:

set interfaces ethernet eth0 vif 10 pppoe 0 egress-qos "1:5 2:5 3:5 4:5 5:5 6:5 7:5"

Also, if the command is doing what you suggest, wouldn't this only work if all your VoIP traffic is already tagged with a value of 1-7?

No, the VLAN tagging is done on the VLAN, not the PPPoE interface. The VLAN header is where the PRI field is - not in any of the PPPoE headers or packets. The egress-qos option is not valid on the pppoe settings - it must be on the VLAN (vif 10) settings.

As I said, I do not understand where the SO_PRIORITY socket field referenced by the left hand side of those settings comes from. Somehow, it seems to come from the DSCP field in the IP header, but that is not what it is documented as. If it were, the documentation would be referencing the IP_TOS field for a socket. While writing this reply, I did finally come across this page:

https://www.rationali.st/blog/dscp-vs-linux-socket-priorities.html

which explains how it seems to work, but it is not official documenation.

Paul1977

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#1493035 16-Feb-2016 09:22

fe31nz:

No, the VLAN tagging is done on the VLAN, not the PPPoE interface. The VLAN header is where the PRI field is - not in any of the PPPoE headers or packets. The egress-qos option is not valid on the pppoe settings - it must be on the VLAN (vif 10) settings.

As I said, I do not understand where the SO_PRIORITY socket field referenced by the left hand side of those settings comes from. Somehow, it seems to come from the DSCP field in the IP header, but that is not what it is documented as. If it were, the documentation would be referencing the IP_TOS field for a socket. While writing this reply, I did finally come across this page:

https://www.rationali.st/blog/dscp-vs-linux-socket-priorities.html

which explains how it seems to work, but it is not official documenation.

Thanks for that, just to make sure I understand:

The left field in the command is the Linux Prio field from the referenced table, and the EdgeRouter automatically knows this value for each packet based on the DSCP field that the Fritz is now assigning the VoIP traffic?

So this command would work just as well (since DSCP 46 and 24 correspond to Linux Prio 2 and 4 respectively)?:

set interfaces ethernet eth0 vif 10 egress-qos "2:5 4:5"

Am I correct that this isn't actually performing any QoS, but rather just tagging the traffic so that QoS is perform on subsequent hops? So therefore not disabling hardware offloading on the EdgeRouter?

hio77

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#1493267 16-Feb-2016 14:42

Paul1977:

Am I correct that this isn't actually performing any QoS, but rather just tagging the traffic so that QoS is perform on subsequent hops? So therefore not disabling hardware offloading on the EdgeRouter?

the idea is to use the CIR on the ufb, where its handled as high probity traffic past your router.

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Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

fe31nz

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+1 received by user: 423

#1493430 16-Feb-2016 20:34

Paul1977:

Thanks for that, just to make sure I understand:

The left field in the command is the Linux Prio field from the referenced table, and the EdgeRouter automatically knows this value for each packet based on the DSCP field that the Fritz is now assigning the VoIP traffic?

So this command would work just as well (since DSCP 46 and 24 correspond to Linux Prio 2 and 4 respectively)?:

set interfaces ethernet eth0 vif 10 egress-qos "2:5 4:5"

Am I correct that this isn't actually performing any QoS, but rather just tagging the traffic so that QoS is perform on subsequent hops? So therefore not disabling hardware offloading on the EdgeRouter?

That is pretty much correct, except that the Linux kernel is a bit behind the times and is referencing the TOS bits rather than the DSCP bits.

I have other DSCP tagged traffic, and I want all the other non-zero tags to be mapped to CIR bandwidth, hence my setting of egress-qos "1:5 2:5 3:5 4:5 5:5 6:5 7:5".

I am not doing any QoS inside my EdgeRouter Lite as that would cut the speed it routes packets to well below my 200 Mbit/s fibre speed by disabling offloading. In any case, there is no need as I do not have any congestion problems on my internal network that would affect the VOIP traffic.

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