[ovs-dev] [post-8024 1/5] Prepend "nw_" to "frag" and "tos" elements.

Justin Pettit jpettit at nicira.com
Fri Nov 11 01:46:26 UTC 2011


On Nov 10, 2011, at 8:51 AM, Ben Pfaff wrote:

> On Wed, Nov 09, 2011 at 11:59:08PM -0800, Justin Pettit wrote:
>> Most of the members in structures referring to network elements indicate
>> the layer (e.g., "tl_", "nw_", "tp_").  The "frag" and "tos" members
>> didn't, so this commit add them.
> 
> The nw_tos members of struct flow and struct ofp_match have different
> meanings, but the comment in struct flow doesn't really hint at that.
> It would be good to be more explicit, e.g. change the comment to "IP
> ToS (including DSCP and ECN)"

Good point.  I've updated it.

> and maybe we should even change the
> member name in struct ofp_match to nw_dscp (or whatever you like).


As you know, the interplay of TOS and DSCP in OpenFlow are a passion of mine.  I've kept that field name "nw_tos", since it's using the bit positions of TOS but only the DSCP portion is matchable.  Assuming OpenFlow 1.2 moves the DSCP match over by two bits, then true DSCP matches (ie, a range of 0-63) will have a name with "dscp" in them.  (I just realized that I broke this convention in cls_rule_set_nw_dscp(), so I'll send out a follow-up patch for that.  Oh joy!)

--Justin





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