Abstract: Methods and server systems for computing fraud risk scores for various merchants associated with an acquirer described herein. The method performed by a server system includes accessing merchant-related transaction data including merchant-related transaction indicators associated with a merchant from a transaction database. Method includes generating a merchant-related transaction features based on the merchant-related indicators. Method includes generating via risk prediction models, for a payment transaction with the merchant, merchant health and compliance risk scores, merchant terminal risk scores, merchant chargeback risk scores, and merchant activity risk scores based on the merchant-related transaction features. Method includes facilitating transmission of a notification message to an acquirer server associated with the merchant.

Abstract: Keepalive packets are transmitted between a sender node and a receiver node at an interval that varies depending on the transit times of previously transmitted keepalive packets. The transit time is based on when a keepalive packet is transmitted to the receiver node and when a corresponding feedback packet is received from the receiver node. The transmission interval varies depending on the path conditions between the sender node and the receiver node, which may be reflected in the transit time.