Network Path and Quality Validation in the Evolved Packet Core

The Internet nowadays plays an imperative role in critical domains such as finance, health, security, entertainment and military where real-time services with guaranteed resources become necessary. Services residing within the application layer in today’s fixed and mobile network environments are abstracting from the underlying network layer, and therefore, assuming pure IP connectivity without taking into consideration the in-network services as Quality-of-Service (QoS) guarantees, security and mobility, and routing decisions. These services assuming best-effort data transport without demanding specific QoS, routing schemes (e.g. shortest, most reliable path, etc.). In comparison to the best-effort data transport, real-time services require reliable transport of packet data flows starting at the device going through the access and core networks into autonomous networks towards a service. End-to-end monitoring provides QoS information along the entire data path. Analyzing all or most parts of a specific packet data flow through fragmented heterogeneous network domains is more complex and requires distributed monitoring techniques. Furthermore, end-to-end monitoring provides only an overall performance measurement, but doesn’t expose QoS information on a per-hop basis through the network. However, these measurements are required to optimize individual network parts through the identification of loops, significant delays or packet loss due to overload situations. This article focuses on the validation of data flows in fixed and mobile networks through the individual network parts, i.e. QoS per hop validation. In particular, the focus is only on the core network part of the Evolved Packet System (EPS) and not on the radio network part (LTE), because the latter one utilizes the shared medium radio and negatively effects the measurement due to packet loss and additional delays. The Packet-Tracking monitoring tool [4] developed within the G-Lab DEEP project1, is presented as a software solution for network path and quality monitoring. It utilizes distributed hash based sampling technique to keep up with increasing data rates.