QoS Ingress shaping based on IP


Hi Gents,

I’m redirecting the downstream traffic through the IFB interface in order to do an IP-based shaping on the ingress.

I couldn’t get it to work and then I noticed that it seems like I can’t do IP matching on the IFB (when debugging with tcpdump I saw the traffic still encapsulated). Could you please confirm this? As if this is the case, I don’t see many reasons why IFB would be useful…



Problem identified.

Seems like redirecting from VLAN interface to ifb0 and combined with an ifb0 out shaping into classes by IP rules doesn’t work due to the following:

tc -s filter show interface ifb0
filter parent 1: protocol all pref 138 u32 fh 889::800 order 2048 key ht 889 bkt 0 flowid 1:8b  (rule hit 251339 success 0)
  match <ip_in_hex_format>/ffffffff at 16 (success 0)

However using 802.1Q the destination IP doesn’t start at offset 16 (as 802.1Q tagging adds extra 4 octets to the Ethernet frame), it starts with offset 20.

After I realized the above I decided to test it and I did eth0 (no vlan) redirect to ifb0 with IP-based out shaping and it worked.

Could you please guys confirm my theory before I submit a bug report?

Kind regards,