[DISPATCH-10] Add link-cost for route computation

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.1
• Fix Version/s: 0.6.0
• Assignee: Ted Ross
• Reporter: Ted Ross
• Created: 30/Jan/14 18:26
• Updated: 20/Nov/17 18:40
• Resolved: 22/Apr/16 21:56

Description

The route computation algorithm has the ability to take link cost into consideration when choosing best paths. Inter-router links need to be configured with an optional cost metric that is fed into the routing algorithm.
Inter-router connection cost is specified in two places in the configuration: The inter-router listener and the inter-router connector using a new attribute called "cost". If the cost attribute is absent, the cost defaults to 1, the lowest possible cost for an inter-router jump.
When a connection is established between routers, the Open.properties map will contain an entry for a non-default cost. Each side of the connection compares it's cost to the cost provided by the peer and uses the higher value as the cost for the connection. There is no support currently for asymmetric cost (even though the internal routing engine can support it).
The cost can be configured to influence the routing algorithm to favor certain inter-router connections over others, or to identify long-haul connections as having higher cost to keep the message forwarding for "closest" in a region if there are any consumers in that region.

Issue Links

• is cloned by: DISPATCH-693 Dispatch - Add link-cost for route computation
• is depended upon by: DISPATCH-208 Closest semantics forwards improperly in multi-router network