CORRECTION Re: [EFM] EFM Requirements
Harry/Matt
At 08:09 PM 8/20/01 -0400, Matt Squire wrote:
Harry Hvostov wrote:
>
> Matt,
>
> For the record, the actual stream transport for VoIP is done via
RTP/RTCP -
> application
> layer protocols. Needless to say, these protocols would rely on the
QoS
> mechanisms supported at L2/L3. For an example of mapping the MGCP
session
> descriptions into L2 QoS parameter
> sets please see PacketCable 1.0 Dynamic QoS specification at
>
www.packetcable.com.
The spec is publicly available.
>
So what. At the Ethernet level a packet has
priority.
For the record: At the Ethernet level, a packet has NO priority.
There is no mechanism to manipulate or order Priorities anywhere in
802.3
There is a field allocated in the 802.1Q VLAN TAG that allows "user
priority" information to be transported across Ethernet in an agreed
upon location within a packet within a particular Ethernet protocol
(802.1QTagType: 0x81-00)
This information location of not normative in 802.3
This information acted upon anywhere in 802.3
This priority information is a feature of 802.1Q, not 802.3
There are many other Ethernet protocols,each with their own identifying
Type number. More than a few of them have a field for priority
information. We (802.3) treat those protocols in exactly the same way
that we treat packets of the 802.1Q protocol type, that is, we send them
and receive them between the MAC Client and the medium on a first-in,
first-out basis. That's all.
Geoff