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| 8.1 |  | Quality of Service Requirements |
| 8.1.2 |  | Loss |

Loss refers to the percentage of packets that fail to reach their destination. Loss can result from errors in the network, corrupted frames and congested networks. With modern switched and optically based networks, corrupted frames and packet losses due to network noise, interference and collisions are becoming rare. Many of the packets lost in an optimized network are deliberately dropped by networking devices to avoid congestion. For many TCP/IP based traffic flows, such as those associated with file and print services, small numbers of lost packets are of little concern as TCP/IP’s retransmission mechanism will ensure their eventual arrival. However, for UDP traffic associated with real-time applications such as streaming media and voice, retransmission is not feasible and losses are less tolerable. As a guideline, a highly available network should suffer less than one percent loss and for voice traffic the loss should approach zero percent.