Fundamental Information Technology Engineer Examination (FE) | Subject A Network and Database Questions 01

The destination matches the /8, /16, /24, and default routes. Of these, 10.20.30.0/24 has the longest prefix and is the most specific, so Exit C is selected. Route-table order and the broader /8 route do not take priority.

The effective transfer rate is 100 Mbps × 0.8 = 80 Mbps. The 200 MB file contains 1,600 Mbit, so transfer time is 1,600 Mbit ÷ 80 Mbps = 20 seconds. Sixteen seconds ignores utilization, while 25 seconds divides the resulting 20 seconds by 0.8 again and applies utilization twice.

An ARP request broadcasts a question on the local LAN asking which host owns the specified IPv4 address. Q, the owner, returns an ARP reply containing its MAC address. P cannot initially unicast to Q because that destination MAC address is unknown, and traffic to a host on the same subnet does not need the gateway's MAC address.

These conditions prioritize low delay over complete recovery from loss, so UDP is suitable because it does not guarantee delivery or order and does not retransmit at the transport layer. TCP provides reliable, ordered delivery and retransmits after loss, which can delay the arrival of older audio data.

An MX record identifies the mail exchange server that accepts email for a domain. An A record maps a host name to an IPv4 address, CNAME maps an alias to its canonical name, and PTR is mainly used to map an address back to a name.

The non-null foreign-key value 30 must exist among the referenced Departments.dept_id values. Because department 30 is absent, referential integrity is violated and the insertion is rejected. A foreign key does not create the referenced row automatically, and multiple employees may ordinarily reference the same department.

Grouping by department gives averages of 80 for D01, 90 for D02, and 75 for D03. HAVING applies AVG(score) ≥ 80 after aggregation, so two rows for D01 and D02 are returned in department order. It is not a WHERE condition that selects individual rows whose score is at least 80.

Both updates form one transaction, so either all must succeed or all must be undone. Because the failure occurs before crediting B, atomicity requires rolling back the debit from A and leaving no partial result. Durability preserves committed results after a failure; it does not permit a partial transaction to be committed.

T1 waits for Y held by T2, while T2 waits for X held by T1. This circular wait prevents either transaction from progressing and is a deadlock. A DBMS commonly detects it and aborts one transaction to release its locks. The decisive condition is the wait cycle, not merely a long wait.

A B-tree index can use key ordering for timestamp comparisons and range conditions. Inserts, deletes, and updates to indexed values also require index maintenance. Whether the optimizer actually uses the index depends on factors such as table size, selectivity, and statistics, so it is not guaranteed to be fastest for every query.