Explanation:
In a dial-in mode, the destination initiates a session to the router and subscribes to data to be streamed. Dialin mode is supported over gRPC in only 64-bit platforms In a dial-out mode, the router initiates a session to the destinations based on the subscription. All 64-bit IOS XR platforms (except for NCS 6000 series routers) support gRPC and TCP protocols. All 32-bit IOS XR platforms support only TCP.
Reference:
https://www.cisco.com/c/en/us/td/docs/iosxr/asr9000/telemetry/b-telemetry-cg-asr9000-61x/b-telemetry-cgasr9000-
61x_chapter_010.html#id_36445

Unequal cost load balancing is a feature that allows traffic to be distributed across unequal-cost paths to the same destination, which can increase network utilization and improve overall performance.
EIGRP (Enhanced Interior Gateway Routing Protocol) and OSPF (Open Shortest Path First) are two routing protocols that support unequal cost load balancing.
In EIGRP, unequal cost load balancing can be achieved by adjusting the "variance" parameter, which is a multiplier that determines the maximum metric of a feasible successor. The feasible successor is a backup route that meets the feasibility condition, which means its reported distance (the sum of the metric from the successor router and the advertised distance to the destination) is less than the current best path's metric. By default, EIGRP only considers successors with the same metric as the best path, but by increasing the variance, EIGRP can include feasible successors with higher metrics.
In OSPF, unequal cost load balancing can be achieved by enabling the "variance" command, which allows OSPF to use paths with metrics that are up to a certain multiple of the best path's metric. For example, if the variance is set to 2, OSPF can use paths with a metric that is up to twice the metric of the best path.
IS-IS (Intermediate System to Intermediate System) and BGP (Border Gateway Protocol) do not support unequal cost load balancing.
RIPng (Routing Information Protocol next generation) is a distance-vector routing protocol that does not support unequal cost load balancing.

A redundant triangle topology enables equal-cost multipath (ECMP) routing, ensuring that traffic (including VoIP calls) is instantly rerouted over another path without waiting for EIGRP convergence, thus achieving the fastest possible convergence and no call disruption.

Explanation:

https://xrdocs.io/telemetry/blogs/2017-01-20-model-driven-telemetry-dial-in-or-dial-out/

There are 4 methods how you can prevent becoming a transit AS:
- Filter-list with AS PATH access-list.
- No-Export Community.
- Prefix-list Filtering
- Distribute-list Filtering
https://networklessons.com/bgp/bgp-prevent-transit-as