Dispatch Router is an AMQP router and as such, it provides extensions, code-points, and semantics for routing over AMQP. This page documents the details of Dispatch Router’s use of AMQP.
The following Message Annotation fields are defined by Dispatch Router:
Field | Type | Description |
---|---|---|
x-opt-qd.ingress | string | The identity of the ingress router for a message-routed message. The ingress router is the first router encountered by a transiting message. The router will, if this field is present, leave it unaltered. If the field is not present, the router shall insert the field with its own identity. |
x-opt-qd.trace | list of string | The list of routers through which this message-routed message has transited. If this field is not present, the router shall do nothing. If the field is present, the router shall append its own identity to the end of the list. |
x-opt-qd.to | string | To-Override for message-routed messages. If this field is present, the address in this field shall be used for routing in lieu of the to field in the message properties. A router may append, remove, or modify this annotation field depending on the policy in place for routing the message. |
x-opt-qd.phase | integer | The address-phase, if not zero, for messages flowing between routers. |
The following Capability values are used in Sources and Targets.
Capability | Description |
---|---|
qd.router | This capability is added to sources and targets that are used for inter-router message exchange. This capability denotes a link used for router-control messages flowing between routers. |
qd.router-data | This capability is added to sources and targets that are used for inter-router message exchange. This capability denotes a link used for user messages being message-routed across an inter-router connection. |
The following dynamic-node-properties are used by Dispatch in Sources.
Property | Description |
---|---|
x-opt-qd.address | The node address describing the destination desired for a dynamic source. If this is absent, the router will terminate any dynamic receivers. If this address is present, the router will use the address to route the dynamic link attach to the proper destination container. |
The following AMQP addresses and address patterns are used within Dispatch Router.
Pattern | Description |
---|---|
_local/<addr> | An address that references a locally attached endpoint. Messages using this address pattern shall not be routed over more than one link. |
_topo/0/<router>/<addr> | An address that references an endpoint attached to a specific router node in the network topology. Messages with addresses that follow this pattern shall be routed along the shortest path to the specified router. Note that addresses of this form are a-priori routable in that the address itself contains enough information to route the message to its destination. The ‘0’ component immediately preceding the router-id is a placeholder for an _area_ which may be used in the future if area routing is implemented. |
<addr> | A mobile address. An address of this format represents an endpoint or a set of distinct endpoints that are attached to the network in arbitrary locations. It is the responsibility of the router network to determine which router nodes are valid destinations for mobile addresses. |
Address | Description |
---|---|
$management | The management agent on the attached router/container. This address would be used by an endpoint that is a management client/console/tool wishing to access management data from the attached container. |
_topo/0/Router.E/$management | The management agent at Router.E in area 0. This address would be used by a management client wishing to access management data from a specific container that is reachable within the network. |
_local/qdhello | The router entity in each of the connected routers. This address is used to communicate with neighbor routers and is exclusively for the HELLO discovery protocol. |
_local/qdrouter | The router entity in each of the connected routers. This address is used by a router to communicate with other routers in the network. |
_topo/0/Router.E/qdrouter | The router entity at the specifically indicated router. This address form is used by a router to communicate with a specific router that may or may not be a neighbor. |
Qpid Dispatch is manageable remotely via AMQP. It is compliant with the emerging AMQP Management specification (draft 9).
Differences from the specification: