Internet was developed for text-oriented network applications when line transmission rate was very low while Bit Error Rate (BER) was very high.

• Internet是在线路传输速率低、误码率高的通信条件下,以文本数据传输为主的应用背景下诞生的网络,历史证明它所提供的“尽力而为”服务完全能够满足文本数据传输服务质量的需要。