ltm rule namespace MR

iRule(1)		      BIG-IP TMSH Manual		      iRule(1)



MR
       Namespace MR

DESCRIPTION
       The MR namespace contains iRule commands that work with the message
       routing framework (MRF).

       MRF routes messages between two endpoints via a message routing proxy
       (MR proxy) associated with each endpoint.  Certain application layer
       protocols use the MRF to route protocol-specific messages.  A received
       message is said to "ingress" from one protocol-specific endpoint to the
       MR proxy.  A sent message is said to "egress" from the MR proxy to the
       protocol-specific endpoint.

       Associated Events:
	   MR_INGRESS  - Triggered when an incoming message reaches the MR
       proxy after the protocol filter.
	   MR_EGRESS   - Triggered when an outgoing message is ready to be
       sent to the protocol filter.
	   MR_FAIL     - Triggered when an outgoing message is unable to be
       routed.
	   MR_DATA     - Triggered when an incoming message has a streaming
       payload.

       MR iRule commands operate within a Tcl context associated with the
       connection flow between the endpoint and the MR proxy.  The ingress and
       egress parts of a message's journey therefore operate in separate Tcl
       contexts.  The Tcl context contains the Tcl variables and execution
       state of the currently executing iRule event.  Only one iRule event can
       execute at a time on a connection flow, therefore messages queue to
       execute their iRule events.

       In many MR protocols, messages belong to independent transactions that
       are carried over the same network connection flow.  It is highly
       desirable for messages sharing a connection flow to execute their
       iRules independently of other messages.	This provides the following
       advantages and behavior changes:
	   * A message does not need to wait for an unrelated message to
       complete an event in order to execute its own event.
	   * Messages sharing a connection flow may exit the flow in a
       different order than they entered.
	   * Tcl variables cannot be overwritten between events by another
       message.  This capability may be enabled in the protocol-specific
       router profile via the irule-scope-message attribute, only for
       protocols that currently support it.  Before enabling irule-scope-
       message for a protocol, the user's iRules should be examined and if
       necessary adjusted and tested, to ensure they do not rely on sharing a
       Tcl context between messages on a connection flow.

HINTS
SEE ALSO
BIG-IP				  2019-05-10			      iRule(1)