The following versions are recommended because they have scalability enhancements and better debug/syslogs messages:
- IOS-XE 3.9 or 3.10 (long live)
- IOS 15.3(2)T latest build
IOS 15.2(3)T and IOS-XE 3.6
The simplification initiative starting from IOS 15.2(3)T and XE 3.6 brings a lot of improvements. The current code does not have utilization and range resolvers. PfR is doing first qualification of the links based on utilization, followed by any other resolver, followed by range at the end.
Table below summarizes the changes for load-balancing and resolvers.
|Current Solution||After 15.2(3)T / XE 3.6|
|Support utilization and range resolvers||Remove utilization and range resolvers|
|Automatic learning disabled||Automatic learning enabled by default (reports every minute, forever)|
|Mode route control disabled||Mode route control on by default|
|Delay, range, utilization resolvers are the default resolvers||Load-balancing is used as the last resolver and cannot be disabled. Resolver range and utilization removed.|
|Do random resolver for all qualified exits that satisfy the configured criteria||Do load balancing for all qualified exits that satisfy the configured criteria then random selection|
|Cost resolver can be configured with a higher priority than performance resolver in a policy||No priority option for resolver cost-min. It is always handled after any performance resolver|
|Trigger range OOP by comparing the load of an exit to all other exits.||Trigger range OOP by comparing the load of an exit to all other exits in the same group.|
|Check the soft limit before calling the resolver||Check soft limit of all exits before entering the resolver. If none of exits are below the limit, make selection by ignoring the soft limit.|