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Objective 1.13200-301

1.13 Describe switching concepts.

Objective 1.13 sits in Network Fundamentals, which carries 20% of the CCNA exam. The questions below are original, written from the official objective title above, and each explanation cites the Cisco page it rests on.

Objective title verbatim from the official objectives. Cisco exam page ↗

A worked example

Shown solved, with the whole explanation open: this is what every question here carries.

1-13Network FundamentalsModerate

A workstation is unplugged at lunchtime. Ten minutes later its address is gone from the switch's forwarding database, although nothing else changed. What removed the entry?

The ageing timer expired for that hostCorrect · your answerCorrect. Nothing was heard from the address inside the holding period, so the entry lapsed.
The port was placed in a blocking stateA blocked port stops forwarding, which is a spanning tree state rather than a reason to forget an address.
A topology change flushed the databaseA topology change shortens the holding period, and the question states nothing else changed.
The address was learned on another portRelearning on a second port moves an entry rather than deleting it, and the host was unplugged.

Correct.

Concept

A learned forwarding entry is a cache of where a source was last heard, so it has to expire. Without expiry the table would fill with stations that have left and would keep sending frames toward ports where nothing answers.

Why A

Each learned entry is held for a fixed period after the last frame from that address, five minutes by default. Silence past that window removes it, and the next frame for the address is flooded until the station speaks again.

Source

#switching#mac address table#ageing

Now you: objective 1.13 questions

No account needed. The explanation opens when you answer.

Sample question 1 of 3

1-13Network FundamentalsModerate

A traceroute between two hosts on different floors returns one hop, even though four switches sit in the path. Why do the switches not appear?

Sample question 2 of 3

1-13Network FundamentalsModerate

A patch cable is accidentally run between two access ports on the same switch, with loop protection turned off. Within seconds every port on the switch saturates. What is happening?

Sample question 3 of 3

1-13Network FundamentalsModerate

A capture host is cabled to a switch and has to see every frame entering and leaving a server port. Which switch feature delivers that?

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Read the sources

These are the official pages the questions above cite. Reading them is studying the objective from the primary source, which is what the explanations point you toward anyway.

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