Free Cisco 400-007 Actual Exam Questions - Question 11 Discussion

Question No. 11
When designing a WAN that will be carrying real-time traffic, what are two important reasons to
consider serialization delay? (Choose two )
Select all that apply, then reveal solution.
US
CE
Carlos E.
2026-02-21

E (only packet size and line rate affect serialization delay, so B/D are off)

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BO
Brian O.
2026-02-16

E, C. E makes sense since serialization delay depends on both packet size and link speed, which lines up with what I know. C says serialization delay is the time to transmit the packet on the media, which seems accurate if you think of serialization as the actual bit-by-bit transmission time. Even if it’s a bit ambiguous, propagation delay is a separate concept from serialization delay, so I’m okay with including C here. A and B don’t quite work because serialization delay isn’t fixed—it varies with packet size, so those options feel off.

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OJ
Osama J.
2026-02-14

E imo, serialization delay varies with both line rate and packet size, so that part’s clear. A is wrong because serialization delay isn’t invariable—it depends on packet size too, not just line rate.

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SH
Sohail H.
2026-02-05

C/E? C describes serialization delay as the time to transmit the packet on the physical media, which aligns with it being the bit-by-bit output time. Meanwhile, E adds that it depends on both the interface line rate and packet size, which matches the basic formula for serialization delay. A and D don’t fit because the delay isn’t invariable—it changes with packet size and line rate. B is off since the type of packet doesn’t directly affect serialization delay, just its size does. So C and E together cover both what serialization delay is and what it depends on.

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SH
Sohail H.
2026-02-01

E, C. Serialization delay definitely depends on both the line rate and packet size, so E makes sense. I also think C tries to capture the essence of serialization delay—it's basically the time to push all packet bits onto the wire. Even if the wording is a bit off or vague, it’s describing what serialization delay really is, unlike some options that add unrelated variables like packet type. So I’d pick E and C here.

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LH
Luke H.
2026-01-27

Not B, serialization delay isn't variable based on packet type, just size and line rate.

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LH
Luke H.
2026-01-19

C/E? Serialization delay is definitely about how long it takes to push the packet bits onto the wire, so C fits. And E covers the two main factors: line rate and packet size. Makes sense.

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SR
Sohail R.
2026-01-17

C and E seem right here, serialization depends on packet size and line rate.

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