Kalle Valo wrote:
Hello, me and Patrik have been pondering what's the proper way for user space applications to do packet classification to get the benefits from WMM. VoIP application is a good example here. For the time being we have identified three different methods: 1. SO_PRIORITY with values 0-7 (we used this in nokia n810) 2. SO_PRIORITY with values 256-263 (used by mac80211) 3. IPv4 DSCP field with values 0-7 (used by mac80211) Method 1 is easy, applications need to just use setsockopt() and be done with it. I don't know how widely supported values 0-7 are, but at least they make sense. The problem is that priority is used only in the first link, rest of the route is not able to benefit from the classification. Method 2 (priorities 256-263) doesn't sound very portable. I doubt if any other stack or driver (even non-wifi ones) use these values. Otherwise this is similar with Method 1. Method 3 (IPv4 DSCP field) feels most portable to us, at least most, if not all, wifi drivers should use it. And, in theory, the receiver should also benefit from the classification, unless ISPs modify it of course. But the standardisation for IPv4 QoS bits is a mess and I don't really understand where the use of DSCP bits (as used in WMM implementations) is specified. Also I was told that root privileges are needed to set this and that's somewhat cumbersome from application developer's point of view.
What do think of also supporting a method 4, VLAN priority field (0-7)? -ack -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
