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| 8.2 |  | Quality of Service Mechanisms |
| 8.2.2 |  | Best-effort service |

Best-effort is a single service model in which an application sends data whenever it must, in any quantity, without requesting permission or first informing the network. For best-effort service, the network delivers data if it can, without any assurance of reliability, delay bounds, or throughput. The Cisco IOS QoS feature that implements best-effort service is FIFO queuing. FIFO is the default method of queuing for LAN and high speed WAN interfaces on switches and routers. Best-effort service is suitable for a wide range of networked applications such as general file transfers, e-mail and Web browsing.