An engineer is investigating a network congestion issue with an eBGP peer. Which two metrics are impacted by high congestion in an external network? (Choose two.)

Question

Options

• ABGP reachability
• Bpacket loss
• Clatency
• DDNS availability
• EBGP convergence time

• A
  4% (2)
• B
  94% (46)
• D
  2% (1)

Explanation

High congestion in an external network directly causes packet loss (B) and latency (C) because congested links drop packets when buffers overflow and introduce queuing delays - these are the two fundamental, immediate symptoms of any network congestion event.

Why the distractors are wrong:

• A (BGP reachability): BGP sessions are highly resilient to transient congestion; a peer only becomes unreachable if the session drops entirely, which requires sustained, severe packet loss - not congestion itself.
• D (DNS availability): DNS is an application-layer service unrelated to BGP path congestion; a congested eBGP link doesn't inherently affect DNS resolution unless DNS traffic traverses that exact path.
• E (BGP convergence time): Convergence time is a control-plane metric affected by route flaps, timer configurations, and topology changes - not by data-plane congestion on an existing stable session.

Memory tip: Think "congestion = clogged pipe." A clogged pipe slows things down (latency) and causes overflow/drops (packet loss). Everything else - BGP sessions, DNS, convergence - lives above or outside the physical pipe and requires more than just congestion to fail.

No community discussion yet for this question.