Thanks Ted, this is very helpful. cheers Noel
On Wed, Jun 3, 2015 at 12:52 AM Ted Ross <[email protected]> wrote: > On 06/02/2015 07:09 AM, Noel OConnor wrote: > > Hi, > > I'm going through the docs for the dispatch router and I've a few basic > > questions around entries the qdrouterd.conf file > > > > [1] In the router sections a router can have a mode of endpoint but this > > mode isn't explained. > > The "endpoint" mode is not relevant to the actual router. It is there > to support another project that uses the dispatch library as a > dependency. This should be removed from the docs/config-spec. > > > > > [2] In the listener and connector sections, they both can have roles > which > > are on-demand. Does this mean these listeners and connectors are > > started/stopped arbitrarily and is there some sort of config for this ? > > The on-demand role is only meaningful for connectors. It means that the > outgoing connection is only established when it is needed. On demand > connectors are indexed by a name and the name can be used in either a > waypoint or a linkRoutePattern. Both waypoints and linkRoutePatterns > can have an external container (e.g. a broker) associated with them. > > LinkRoutePatterns establish the on-demand connection at startup. > Waypoints are supposed to establish the connection only when there are > subscriptions from or messages sent to the connected container. > > > > > [3] The waypoints and fixed addresses have a phase element. Is the phase > > concept explained somewhere ? > > These are probably not sufficiently explained. Also, waypoints are > somewhat experimental. We plan to improve them and make them easier to > configure/provision. > > The phase concept is key to waypoints because waypoints define a > multi-segment path for an address. For example, a waypoint can > represent a queue on a broker. There are two routing paths for this > queue: messages flowing _to_ the queue, and messages flowing _from_ the > queue. Messages to the queue are phase 0 and messages from the queue > are phase 1. > > Please note that the address phases are not visible to endpoints using > the router network. They are only used internally to route messages > from endpoint to waypoint (to other waypoints) and to consumers. > > > > > [4] The differences between linkRoutePattern and Waypoint seem subtle (at > > least to me). When would you use one over the other ? > > Both of these features are used to provide remote (cross-network) access > to things like brokers, but they do it in fundamentally different ways. > > Link routing does the routing at the time the link is attached (like a > virtual circuit to a remote queue). Waypoints do the routing on each > individual message. > > Link routing provides the full link protocol across the network (i.e. > flow control, message settlement, etc.). Waypoints provide a way to > implement distributed queues (i.e. messages sent to the nearest waypoint > or spread across multiple waypoints with the same address). > > If the link protocol is important (high-resolution flow control, > reliable messaging/exactly-once, transactions, strictly in-order > delivery), then link-routing is the appropriate choice. If these are > less important, waypoints can provide a more flexible way to provide > scale and elasticity. > > > > > thanks for your help > > regards > > Noel > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [email protected] > For additional commands, e-mail: [email protected] > >
