An administrator must optimize the performance of real-time voice and video applications across a WAN link with high packet loss. Which combination of IPSec phase 1 parameters must the administrator…

Question

Options

• Afec-ingress and fsc-egrsss
• Bdpd and dpd-retryinterval
• Cfragmentation and fragmentation-mtu
• Dkeepalive and keylive

• A
  78% (18)
• B
  13% (3)
• C
  4% (1)
• D
  4% (1)

Explanation

Forward Error Correction (FEC) is specifically engineered for real-time traffic over lossy links - it adds redundant data to the stream so the receiver can reconstruct dropped packets without waiting for retransmission. On a high-packet-loss WAN, voice and video can't tolerate retransmission delays, making fec-ingress (correcting inbound loss) and fec-egress (correcting outbound loss) the correct phase 1 parameters. Note: option A contains a typo ("fsc-egrsss") - on a real FortiGate, the correct parameter is fec-egress.

Why the others are wrong:

• B (dpd / dpd-retryinterval): Dead Peer Detection monitors whether the remote IPSec peer is still reachable. It manages tunnel liveness, not packet loss or media quality.
• C (fragmentation / fragmentation-mtu): Fragmentation controls how oversized packets are split to fit MTU constraints. It can reduce drop-on-entry issues but does nothing to recover lost packets for real-time streams.
• D (keepalive / keylive): keepalive is another tunnel-health mechanism; "keylive" is not a real IPSec parameter - it's a pure distractor.

Memory tip: Think FEC = "Fix Every Cut" - it proactively patches packet loss before the application feels it, which is exactly what voice and video need on a wounded WAN link.

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