Yang, Lily L wrote:
I thought this has been the case. The callout protocol is going to transport
and transform the encapsulated application protocol data stream, and hence
has to understand the interaction with that application protocol.
The callout protocol does transport the application messages, but the
callout protocol itself does *not* transform them. As such, it is not
required to understand the application protocol - indeed, protocol
layering rather suggests that the (underlying) callout protocol does
not make any assumptions about the (above) application protocol (just
as it is assumed that TCP does not understand the higher-layer payload
it transports).
There might be good reasons for us to consider characteristics of the
encapsulated application protocol, I'm just wondering where to draw
the line...
-Markus