SixXS::Sunset 2017-06-06

[us] Shadow Hawkins on Monday, 26 October 2015 15:03:54
I'm using AICCU to provide a tunnel and I use QoS tags for VoIP on my edge router, my QoS tags are reaching my server that has AICCU on it, but when they get encapsulated the IPv4 packet drops the DSCP tags so my router can't QoS them properly. Looking at a packet capture I still see the DSCP tags in the IPv6 portion of the packet, but they are missing in the IPv4 portion.
[ch] Jeroen Massar SixXS Staff on Monday, 26 October 2015 15:10:35
As QoS is useless outside of administrative network boundaries, most of the Internet ignores them. The moment your packets go into the tunnel, they are traveling over an unknown network that will thus ignore those QoS fields. Hence, adding them won't make much of a difference. If your own gear needs to know about those fields you should terminate the tunnel at the edge of your administrative domain instead of somewhere in the middle of your network. Note: if you have a Linux kernel and a proto-41 based tunnel one can set the copying behavior using: ip tunnel change <interface> tos 1 That only works for proto-41 aka 'sit' tunnels. That trick does not work for AYIYA as AICCU does not implement it, as noted above, it is mostly useless as networks ignore it. The bigger question you should have is why you are having to use QoS in the first place. Because if you have a full pipe, it is better to fix the usage there or get a bigger pipe. See also BufferBloat

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