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author | Stephen Hemminger <stephen@networkplumber.org> | 2024-01-11 09:39:23 -0800 |
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committer | Stephen Hemminger <stephen@networkplumber.org> | 2024-01-17 09:20:07 -0800 |
commit | 9071483dd20789e14fcea850cf06ff1216f1a64c (patch) | |
tree | ee24457cce74971cb5f69bf2076cd251fe5abd4f | |
parent | 4e3a6bc12072f964e42888350bf6d416788ce254 (diff) | |
download | iproute2-9071483dd20789e14fcea850cf06ff1216f1a64c.tar.gz |
doc: remove ifb README
Most of this document goes back to when IFB was first integrated
and covers the motivation. Only of historical interest.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
-rw-r--r-- | doc/actions/ifb-README | 125 |
1 files changed, 0 insertions, 125 deletions
diff --git a/doc/actions/ifb-README b/doc/actions/ifb-README deleted file mode 100644 index 5fe917146..000000000 --- a/doc/actions/ifb-README +++ /dev/null @@ -1,125 +0,0 @@ - -IFB is intended to replace IMQ. -Advantage over current IMQ; cleaner in particular in in SMP; -with a _lot_ less code. - -Known IMQ/IFB USES ------------------- - -As far as i know the reasons listed below is why people use IMQ. -It would be nice to know of anything else that i missed. - -1) qdiscs/policies that are per device as opposed to system wide. -IFB allows for sharing. - -2) Allows for queueing incoming traffic for shaping instead of -dropping. I am not aware of any study that shows policing is -worse than shaping in achieving the end goal of rate control. -I would be interested if anyone is experimenting. - -3) Very interesting use: if you are serving p2p you may want to give -preference to your own locally originated traffic (when responses come back) -vs someone using your system to do bittorent. So QoSing based on state -comes in as the solution. What people did to achieve this was stick -the IMQ somewhere prelocal hook. -I think this is a pretty neat feature to have in Linux in general. -(i.e not just for IMQ). -But i won't go back to putting netfilter hooks in the device to satisfy -this. I also don't think its worth it hacking ifb some more to be -aware of say L3 info and play ip rule tricks to achieve this. ---> Instead the plan is to have a conntrack related action. This action will -selectively either query/create conntrack state on incoming packets. -Packets could then be redirected to ifb based on what happens -> eg -on incoming packets; if we find they are of known state we could send to -a different queue than one which didn't have existing state. This -all however is dependent on whatever rules the admin enters. - -At the moment this 3rd function does not exist yet. I have decided that -instead of sitting on the patch for another year, to release it and then -if there is pressure i will add this feature. - -An example, to provide functionality that most people use IMQ for below: - --------- -export TC="/sbin/tc" - -$TC qdisc add dev ifb0 root handle 1: prio -$TC qdisc add dev ifb0 parent 1:1 handle 10: sfq -$TC qdisc add dev ifb0 parent 1:2 handle 20: tbf rate 20kbit buffer 1600 limit 3000 -$TC qdisc add dev ifb0 parent 1:3 handle 30: sfq -$TC filter add dev ifb0 protocol ip pref 1 parent 1: handle 1 fw classid 1:1 -$TC filter add dev ifb0 protocol ip pref 2 parent 1: handle 2 fw classid 1:2 - -ifconfig ifb0 up - -$TC qdisc add dev eth0 ingress - -# redirect all IP packets arriving in eth0 to ifb0 -# use mark 1 --> puts them onto class 1:1 -$TC filter add dev eth0 parent ffff: protocol ip prio 10 u32 \ -match u32 0 0 flowid 1:1 \ -action ipt -j MARK --set-mark 1 \ -action mirred egress redirect dev ifb0 - --------- - - -Run A Little test: - -from another machine ping so that you have packets going into the box: ------ -[root@jzny action-tests]# ping 10.22 -PING 10.22 (10.0.0.22): 56 data bytes -64 bytes from 10.0.0.22: icmp_seq=0 ttl=64 time=2.8 ms -64 bytes from 10.0.0.22: icmp_seq=1 ttl=64 time=0.6 ms -64 bytes from 10.0.0.22: icmp_seq=2 ttl=64 time=0.6 ms - ---- 10.22 ping statistics --- -3 packets transmitted, 3 packets received, 0% packet loss -round-trip min/avg/max = 0.6/1.3/2.8 ms -[root@jzny action-tests]# ------ -Now look at some stats: - ---- -[root@jmandrake]:~# $TC -s filter show parent ffff: dev eth0 -filter protocol ip pref 10 u32 -filter protocol ip pref 10 u32 fh 800: ht divisor 1 -filter protocol ip pref 10 u32 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1:1 - match 00000000/00000000 at 0 - action order 1: tablename: mangle hook: NF_IP_PRE_ROUTING - target MARK set 0x1 - index 1 ref 1 bind 1 installed 4195sec used 27sec - Sent 252 bytes 3 pkts (dropped 0, overlimits 0) - - action order 2: mirred (Egress Redirect to device ifb0) stolen - index 1 ref 1 bind 1 installed 165 sec used 27 sec - Sent 252 bytes 3 pkts (dropped 0, overlimits 0) - -[root@jmandrake]:~# $TC -s qdisc -qdisc sfq 30: dev ifb0 limit 128p quantum 1514b - Sent 0 bytes 0 pkts (dropped 0, overlimits 0) -qdisc tbf 20: dev ifb0 rate 20Kbit burst 1575b lat 2147.5s - Sent 210 bytes 3 pkts (dropped 0, overlimits 0) -qdisc sfq 10: dev ifb0 limit 128p quantum 1514b - Sent 294 bytes 3 pkts (dropped 0, overlimits 0) -qdisc prio 1: dev ifb0 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 - Sent 504 bytes 6 pkts (dropped 0, overlimits 0) -qdisc ingress ffff: dev eth0 ---------------- - Sent 308 bytes 5 pkts (dropped 0, overlimits 0) - -[root@jmandrake]:~# ifconfig ifb0 -ifb0 Link encap:Ethernet HWaddr 00:00:00:00:00:00 - inet6 addr: fe80::200:ff:fe00:0/64 Scope:Link - UP BROADCAST RUNNING NOARP MTU:1500 Metric:1 - RX packets:6 errors:0 dropped:3 overruns:0 frame:0 - TX packets:3 errors:0 dropped:0 overruns:0 carrier:0 - collisions:0 txqueuelen:32 - RX bytes:504 (504.0 b) TX bytes:252 (252.0 b) ------ - -You send it any packet not originating from the actions it will drop them. -[In this case the three dropped packets were ipv6 ndisc]. - -cheers, -jamal |