AMQP Specification Transport

AMQP Specification.
Transport
by the Connection endpoint. Note that because each Connection endpoint independently chooses its alias,
incoming and outgoing frames for a given session may use different channel numbers.
A key difference between a Command transport and a datagram transport is that unlike data delivery,
Command execution can fail. The Session protocol is designed to handle this possibility.
Command execution failure is handled as similarly as possible to network failure. This ensures there is only
one recovery procedure for many distinct failure modes. When command execution fails, the Session is
detached just as if a network failure had occurred. The key difference is that when a Command execution
fails, an explicit detach Control is sent. The detach Control communicates precise information about which
Command failed and why. The Sender of the Command can then choose to terminate the Session or recover
from the last successfully executed Command as if from a network failure.
• Messages are proxied through the Session via the transfer Command. Likewise Message
acknowledgements are proxied as acknowledgements to the transfer Command.
• Each link can be configured with independent flow control of message transfers, or if desired the
link flow control can be disabled. Links with flow control disabled are still subject to flow control
of Commands by the Session.
+------------+
| Link | Message Transport (Node to Node)
+------------+
/|\ 0..*
|
|
|
\|/ 0..1
+------------+
| Session | Command Transport (Host to Host)
+------------+
/|\ 0..*
|
|
|
\|/ 0..1
+------------+
| Connection | Frame Transport (Host to Host)
+------------+
AMQP Transport v. 1-0 Page 2 of 83