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BCS-ISEB

ISEB-SWTINT1 · Question #56

Scenario 3 Data is transmitted over the internet as a series of packets. Each packet is sent to its destination via the best available route. The decision on the best available route is made by a…

The correct answer is D. An inspection of the code for this part of the functionality to try to localise the defective parts of the. Option D is correct because the symptoms - emails routed to wrong destinations, intermittently, under peak load - point to a defect in the code that handles destination address matching or routing table lookups, likely a race condition or logic error exposed under concurrent…

Reviews

Question

Scenario 3 Data is transmitted over the internet as a series of packets. Each packet is sent to its destination via the best available route. The decision on the best available route is made by a series of routers on the internet. In order to make the best decision on the route to take, the router: 1) Scans the destination address and matches it against rules set up in a configuration table. 2) Checks the performance of the primary connection to see if it is good enough to send the packet. If not, it seeks an alternative. Routers handle many millions of packets being sent at the same time. Packets can take the form of email messages, data files etc. A serious issue has arisen with emails arriving at the wrong destinations. This is an intermittent problem, and seems to occur only at peak loading times. Which of the following reviews would you recommend to address this issue?

Options

  • AA walkthrough of the requirement specification, to check for errors.
  • BA management review of defects logged and cleared to see if defects are being addressed
  • CA technical review of the industry standard routing protocols to see if they have inaccuracies in
  • DAn inspection of the code for this part of the functionality to try to localise the defective parts of the

How the community answered

(47 responses)
  • A
    36% (17)
  • B
    15% (7)
  • C
    6% (3)
  • D
    43% (20)

Explanation

Option D is correct because the symptoms - emails routed to wrong destinations, intermittently, under peak load - point to a defect in the code that handles destination address matching or routing table lookups, likely a race condition or logic error exposed under concurrent load. A code inspection directly examines the implementation to localise exactly where the faulty logic lives, which is the most targeted and effective action.

Why the distractors are wrong:

  • A is wrong because the requirements likely specify correct routing behaviour; the problem is in the implementation of those requirements, not the spec itself.
  • B is wrong because a management review of historical defect logs is a process-level activity that won't help find this specific bug - it only assesses whether defect tracking is healthy.
  • C is wrong because industry-standard routing protocols (e.g., OSPF, BGP) are well-established and not the source of the problem; the issue is in the code that implements routing, not the protocols themselves.

Memory tip: Match the review type to where the problem lives. Wrong behaviour at runtime = code defect = code inspection. Wrong requirements = walkthrough the spec. Wrong process = management review. "Peak load + wrong destination" screams a code-level concurrency or lookup bug, so go straight to the code.

Topics

#code inspection#defect localization#review types#static analysis

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