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Meaning of fields #210

Open sebelk opened 4 years ago

sebelk commented 4 years ago

Hi,

What is the meaning of fields BE, BK, CS5 and FF that it ouputs in the graphs? I've searched a bit, but I didn't found anything. Thanks in advance!

tohojo commented 4 years ago

sebelk notifications@github.com writes:

Hi,

What is the meaning of fields BE, BK, CS5 and FF that it ouputs in the graphs? I've searched a bit, but I didn't found anything. Thanks in advance!

Those are diffserv markings: BE: Best Effort (marking 0x0) BK: Background (AKA CS1, marking 0x20) CS5: Class Selector 5 (marking 0xa0) EF: Expedited Forwarding (marking 0xb8)

The particular markings were chosen so that the four flows should be put into the four different hardware queues on Linux WiFi devices. Some ISPs also treat diffserv-marked traffic differently, while others just clear all markings. The RRUL test can also be used as a way to discover this...

flent-users commented 4 years ago

Hi Toke,

On Jun 18, 2020, at 15:21, Toke Høiland-Jørgensen notifications@github.com wrote:

sebelk notifications@github.com writes:

Hi,

What is the meaning of fields BE, BK, CS5 and FF that it ouputs in the graphs? I've searched a bit, but I didn't found anything. Thanks in advance!

Those are diffserv markings: BE: Best Effort (marking 0x0) BK: Background (AKA CS1, marking 0x20) CS5: Class Selector 5 (marking 0xa0) EF: Expedited Forwarding (marking 0xb8)

The particular markings were chosen so that the four flows should be put into the four different hardware queues on Linux WiFi devices.

Except they are not. The default DSCP to WMM AC mapping puts these into:

BE -> AC_BE BK -> AC_BK CS5 -> AC_VI EF -> AC_VI

AC_VO is not exercised by the rrul set. The rrul_cs8 test however will put two flows in each AC if the default mapping is used: CS0 -> BE -> AC_BE CS1 -> BE -> AC_BK CS2 -> BE -> AC_BK CS3 -> BE -> AC_BE CS4 -> BE -> AC_VI CS5 -> BE -> AC_VI CS6 -> BE -> AC_VO CS7 -> BE -> AC_VO

This comes as the default mapping basically just looks at the TOS precedence, or so.

Some ISPs also treat diffserv-marked traffic differently, while others just clear all markings. The RRUL test can also be used as a way to discover this...

Again I humbly propose the rrul_cs8 test for this, many ISPs also use the 3 TOS precedence bits (because some hardwware software only allows for 3 priority bits).

Best Regards Sebastian

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