The E4219A ATM Network Impairment Emulator module provides the capability to insert five impairment typesCell loss, cell error, cell misinsertion, and cell delay into an ATM cell stream at rates up to 155 Mb/s. You can emulate noisy transmission lines, bufferring delays, satellite hops, traffic policing, switch malfunctions, etc. The E4219A helps you stress test ATM services by realistically emulating an imperfect network. Voice, data, and video services may run smoothly on uncongested trial networks, but real networks usually exhibit some degree of impairment, especially when operating under adverse conditions.