flent icon indicating copy to clipboard operation
flent copied to clipboard

Meaning of fields

Open sebelk opened this issue 4 years ago • 2 comments

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!

sebelk avatar Jun 18 '20 11:06 sebelk

sebelk [email protected] 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...

tohojo avatar Jun 18 '20 13:06 tohojo

Hi Toke,

On Jun 18, 2020, at 15:21, Toke Høiland-Jørgensen [email protected] wrote:

sebelk [email protected] 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

— You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or unsubscribe.


Flent-users mailing list [email protected] http://flent.org/mailman/listinfo/flent-users_flent.org

flent-users avatar Jun 18 '20 13:06 flent-users