[hono-dev] Downstream traffic shaping

["Hudalla Kai (INST/ECS4)" <kai.hudalla@xxxxxxxxxxxx>]

Hi list,

at the moment the protocol adapters use a single AMQP session for forwarding
telemetry data and events downstream to the AMQP Messaging Network.

This means that all tenants share the same session window which is used to limit
the number of messages that can be "in flight", i.e. forwarded downstream already
but not settled by the consumer yet. This is an important mechanism for keeping
the system stable and preventing running out of memory if devices send more
messages than we can handle.

However, with the current configuration, i.e. using a single session for all
tenants, we also allow a single tenant to use up all of the available session
window while other tenants' devices get no chance to send their messages
downstream.

FMPOV it would make more sense to use a separate session per tenant, having a
dedicated session window for each tenant. This should help in preventing that a
single tenant uses up all of the system's resources alone.

This, of course, requires that the downstream AMQP Messaging Network supports the
usage and configuration of multiple sessions per connection (which for example
Qpid Dispatch Router does).

WDYT?

-- 
Mit freundlichen Grüßen / Best regards

Kai Hudalla
Chief Software Architect

Bosch Software Innovations GmbH
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