Overview of eMDI
Definition
IP networks transmit an increasing number of services, of which voice and video services are particularly sensitive to packet loss and jitter. It is therefore critical that network faults are quickly detected and located. Enhanced Media Delivery Index (eMDI) is able to meet such needs. eMDI is a network quality monitoring and fault demarcation solution designed for video and audio services. It can monitor specified service packets on each node of an IP network in real time, and quickly demarcate the faulty network segment based on the monitoring results provided by one or more nodes.
Packet Conservation Algorithm for Internet (iPCA) is another commonly used network quality monitoring technology. However, eMDI is more suitable for monitoring the quality of audio and video services. This is because eMDI provides more monitoring indicators, such as the jitter and out-of-order packet rate, and can be deployed on a single node.
Deployment
- Single-node deployment: As shown in Figure 1, eMDI is deployed on a single node (known as the monitoring point) to locate faults on the upstream and downstream network segments of this node.
- Two-node deployment: As shown in Figure 2, eMDI is deployed on two edge nodes, which are the access switch and core switch. In this case, eMDI can demarcate faults on the downstream network segment of the access switch, the network segment between the access switch and core switch, and the upstream network segment of the core switch.
Multi-node deployment: As shown in Figure 3, eMDI is deployed on three or more nodes. In this case, eMDI can demarcate faults on the downstream network segment of the access switch, the network segment between the access switch and aggregation switch, the network segment between the aggregation switch and core switch, and the upstream network segment of the core switch. For example, if eMDI detects packet loss on the aggregation switch and core switch but not on the access switch, it determines that the fault occurs on the network segment between the access switch and aggregation switch.
