Comprehensive and Detailed Explanation:
Key Factors Affecting FTP Performance:
Tail Drop and TCP Synchronization (A)✅
Tail Dropcauses TCPglobal synchronization, reducing FTP speeds drastically when congestion occurs.
Since FTP isTCP-based, packet loss due to tail drop forcesTCP retransmissions, further degrading performance.
Priority Preemption by Video Traffic (D)✅
UDP-based real-time video trafficis often prioritized overTCP-based trafficto avoid jitter and packet loss.
If video traffic hashigher QoS priority, FTP bandwidth may bepreempted, leading toslow speeds.
Incorrect Options:
❌Option B:PQ scheduling typically prioritizes latency-sensitive traffic (VoIP), but this scenario does not mention priority queuing for FTP.
❌Option C:No information about an explicitrate limiton FTP traffic.
????Reference:Huawei HCIE Datacom – QoS and Congestion Control
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