Brian E Carpenter wrote:
I have to agree that e2e cannot create network level QoS that isn't
available -
if the best path available can't offer the desired QoS, no end system
magic can
achieve that QoS. But it can at least make the best use of the QoS
available,
e.g. by reducing a streaming data rate to avoid random loss.
The problem is that the meaning of "end" varies. For example,
with mobility, a home agent is an end and with multicast, some
entity which manages a group is an end (which is why dense
mode multicast with no such entity does not scale).
As for QoS, it can be said that all the intermediate routers are
ends.
In a sense, systems on a path between a source and a destination
may be ends, as long as the path is determined dynamically and
the systems hold dynamic state only, because the systems have
proper knowledge on the ongoing communication.
In a sense, "end" means a system with proper knowledge and control
on the ongoing communication.
For example, as for QoS, PDP, which definitely is not "end" with
limited knowledge and control, destroyed E2E property.
Masataka Ohta
_______________________________________________
Ietf mailing list
Ietf(_at_)ietf(_dot_)org
https://www1.ietf.org/mailman/listinfo/ietf