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TFTP and FTP Operations for System Images and Configuration Management

10 questions

All types10Multiple choice4Multiple select4Ordering2
Question 1Question →

During a network maintenance window, a network engineer attempts to transfer a software image to a Cisco IOS XE switch located across an enterprise WAN link with mild latency and occasional packet loss. When using Trivial File Transfer Protocol (TFTP), the transfer repeatedly stalls and experiences severe throughput degradation whenever a single packet is dropped. However, when switching to File Transfer Protocol (FTP) over the same link, the transfer completes smoothly despite identical network conditions. Which underlying transport protocol characteristic explains why FTP recovers from packet loss far more efficiently than TFTP during file transfers?

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Answer: FTP operates over TCP using dynamic sliding window mechanisms and selective acknowledgments, whereas TFTP operates over UDP using a lock-step stop-and-wait acknowledgment mechanism where each individual block must be acknowledged before the next block is transmitted.

Answer

FTP operates over TCP using sliding window mechanisms, whereas TFTP operates over UDP using a lock-step stop-and-wait acknowledgment mechanism where each block must be acknowledged prior to sending the next.
The correct answer highlights the foundational difference in flow control and reliability mechanics. FTP utilizes TCP, which features sliding window mechanisms that allow continuous stream transmission and selective retransmission of missing segments. TFTP uses UDP and requires an explicit ACK for every single data block before transmitting the next block (stop-and-wait), creating massive throughput bottlenecks when packets are dropped over WAN links.

Step-by-Step Solution

1
Analyze transport protocols utilized by TFTP and FTP.
TFTP runs over UDP on port 69, while FTP runs over TCP on ports 20 and 21.
Understanding the transport layer foundation determines reliability mechanics.
2
Examine TFTP application-layer behavior during file transfer.
TFTP uses a lock-step (stop-and-wait) protocol design where block NN must be explicitly acknowledged by the receiver before block N+1N+1 can be sent.
Because UDP does not provide native sequence numbers or windowing, TFTP enforces retransmission at the application layer per block.
3
Examine FTP transport-layer behavior during file transfer.
FTP relies on TCP's connection-oriented sliding window flow control, sequence numbers, and cumulative/selective ACKs.
TCP allows multiple segments to be transmitted concurrently without waiting for individual acknowledgments, drastically diminishing loss recovery overhead over WAN links.

Key Concept

TFTP (UDP 69, lock-step stop-and-wait per block) vs FTP (TCP 20/21, sliding windows, reliable streaming)
Question 2Question →

A network engineer is selecting file transfer protocols to manage system images and configuration backups for enterprise edge routers. Which two statements accurately describe how TFTP and FTP differ in their underlying transport and operational characteristics?

Select all that apply

Show answer & explanation

Answer: TFTP relies on connectionless UDP transport using port 69 without native user authentication, whereas FTP uses connection-oriented TCP transport and requires authentication credentials.; FTP establishes separate TCP connections for session control commands and data transfer, whereas TFTP uses a single UDP channel for both data transmission and acknowledgements.

Answer

The correct statements are that TFTP relies on connectionless UDP transport on port 69 without authentication while FTP uses TCP with authentication credentials, and that FTP establishes separate control and data connections whereas TFTP uses a single UDP channel.
TFTP uses connectionless UDP on port 69 without native authentication and handles control and data over a single stream. In contrast, FTP uses connection-oriented TCP, requires user authentication, and separates control signals (TCP 21) from data transfers (TCP 20).

Step-by-Step Solution

1
Analyze transport protocols and authentication requirements of TFTP vs FTP
TFTP runs over connectionless UDP port 69 with no built-in user authentication. FTP runs over TCP (control port 21, data port 20) and requires user authentication credentials.
Identify core protocol layer definitions.
2
Evaluate channel structure and flow control mechanics for both protocols
FTP uses dynamic multi-channel TCP sessions (control channel on TCP 21, data channel on TCP 20) with TCP windowing. TFTP uses a simple lockstep stop-and-wait UDP session.
Distinguish control and data plane separation and windowing characteristics.

Key Concept

TFTP vs FTP Transport Protocols and Operational Differences
Question 3Question →

A network administrator needs to back up a Cisco IOS router's running configuration to a remote FTP server that requires user authentication. Arrange the Cisco IOS CLI operational and configuration steps in the correct chronological sequence to perform this transfer.

Drag items to arrange them in the correct order

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Answer

The correct operational sequence begins with defining global FTP credentials ('ip ftp username' / 'ip ftp password'), testing reachability via 'ping', issuing 'copy running-config ftp:', supplying the destination address and file details at the CLI prompts, and finally verifying the completed transfer output.
FTP file management in Cisco IOS relies on control connection authentication and valid network routing. Pre-defining FTP credentials via global configuration ensures seamless connection establishment. Verifying IP reachability with ping confirms path availability before starting data transfer. The interactive 'copy running-config ftp:' command guides the user through target address and filename parameters, culminating in confirmation of the completed transfer.

Step-by-Step Solution

1
Set the global FTP authentication credentials in global configuration mode.
The IOS device is pre-configured to automatically supply credentials when opening FTP control connections.
FTP requires authentication; configuring 'ip ftp username' and 'ip ftp password' prevents connection drops during transfer.
2
Perform a ping to the FTP server IP address.
ICMP reply confirms Layer 3 IP routing and connectivity to the remote server.
Attempting a file transfer without basic connectivity verification leads to timeout failures.
3
Issue the copy running-config ftp: command in privileged EXEC mode.
Cisco IOS starts the interactive copy wizard for FTP.
This command specifies the running configuration as the source data stream.
4
Provide the remote IP address, destination filename, and confirm prompts.
IOS opens TCP port 21 control connection to the FTP server and streams the file over TCP port 20.
Interactive prompts ensure the file is routed to the exact server path designated by the administrator.
5
Examine the CLI summary output indicating bytes copied and elapsed time.
Confirmation that the configuration file was written cleanly to the remote storage directory.
Verifying transfer statistics ensures early detection of incomplete or corrupted transfers.

Key Concept

FTP requires pre-configuration of authentication credentials or URL-formatted inline credentials in Cisco IOS prior to initiating copy operations.
Question 4Question →

A network administrator must transfer multi-gigabyte Cisco IOS XE system software images across an enterprise WAN link to remote routers. The administrator is evaluating file transfer protocols for reliability, session management, and access control. Which two characteristics or operational behaviors distinguish FTP from TFTP, making FTP more appropriate for this large image transfer scenario? (Select TWO.)

Select all that apply

Show answer & explanation

Answer: FTP utilizes TCP as its transport protocol, establishing connection-oriented sessions with sequence acknowledgment and windowing to ensure reliable delivery of large files.; FTP supports authentication using credentials and operates separate control (TCP port 21) and data (TCP port 20) channels for session management.

Answer

FTP is distinguished by its use of TCP for reliable, connection-oriented transfers with windowing and sequence tracking, as well as its support for user authentication and dual-channel operation over TCP ports 20 and 21.
FTP uses TCP as its underlying transport protocol, providing reliable end-to-end flow control, sequencing, and error recovery vital for large file transfers over WANs. Additionally, FTP supports user authentication and separates control management (TCP port 21) from data transmission (TCP port 20).

Step-by-Step Solution

1
Analyze transport protocol characteristics for TFTP and FTP.
TFTP uses UDP (port 69) which is connectionless and unauthenticated, while FTP uses TCP (ports 20 and 21) which is connection-oriented, reliable, and authenticated.
Large Cisco IOS image transfers over WAN links require connection reliability, flow control, and access control.
2
Evaluate features that support multi-gigabyte WAN file transfers.
TCP windowing, sequencing, and error recovery in FTP prevent corruption or transfer aborts upon minor packet drops, unlike basic lock-step TFTP mechanisms.
FTP's separate control (port 21) and data (port 20) channels combined with credential checking enable controlled, robust file transfers.

Key Concept

FTP vs TFTP protocol mechanics, transport ports, and reliability features for system image transfers
Question 5Question →

A network administrator is transferring a Cisco IOS software image from a router to a central backup server using Trivial File Transfer Protocol (TFTP). Which transport-layer protocol and default destination port are used by TFTP for this operation?

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Answer: UDP port 69

Answer

TFTP uses UDP as its transport-layer protocol and listens on default destination port 69.
Trivial File Transfer Protocol (TFTP) is designed to operate over UDP using destination port 69 for basic, low-overhead file management operations.

Step-by-Step Solution

1
Identify the file transfer protocol specified in the question.
The scenario specifies Trivial File Transfer Protocol (TFTP).
Distinguishing between TFTP and standard FTP determines the underlying transport protocol and port number.
2
Determine the transport-layer protocol used by TFTP.
TFTP operates over UDP (User Datagram Protocol).
TFTP uses UDP to avoid the connection establishment overhead of TCP, implementing simple error recovery at the application layer.
3
Identify the standard well-known port number for TFTP.
TFTP uses port 69 as its standard UDP server port.
Port 69 is assigned by IANA for TFTP daemon communication.

Key Concept

TFTP Transport Layer Mechanics and Port Numbers
Question 6Question →

When comparing operational characteristics between TFTP and FTP for managing Cisco IOS device configurations and system images, which two statements accurately describe their key protocol differences? (Select two.)

Select all that apply

Show answer & explanation

Answer: FTP requires session authentication using explicit user credentials, whereas standard TFTP transfers operate without user authentication.; TFTP uses connectionless UDP at the transport layer, whereas FTP uses connection-oriented TCP to guarantee packet delivery.

Answer

The statements highlighting that FTP requires session authentication whereas TFTP operates without authentication, and that TFTP uses connectionless UDP whereas FTP uses connection-oriented TCP, are correct.
FTP uses TCP as its transport protocol (ports 20 and 21) providing connection-oriented reliability and requires user authentication credentials. TFTP uses UDP (port 69) as a simple, unauthenticated file transfer protocol.

Step-by-Step Solution

1
Analyze transport layer protocol assignment for TFTP and FTP.
TFTP uses UDP port 69 as its transport protocol. FTP uses TCP port 21 for control connections and TCP port 20 for data connections.
Understanding transport protocol mappings determines reliability mechanics and port requirements.
2
Analyze authentication features for both file transfer protocols.
FTP supports and mandates user authentication (username/password), whereas TFTP is a simplified protocol without native user authentication capabilities.
Distinguishing authentication capabilities helps identify secure vs simple file transfer operations.

Key Concept

TFTP vs FTP Protocol Operations and Features
Question 7Question →

A network administrator needs to upgrade the Cisco IOS XE system image on a core router from a remote secured FTP server. Arrange the CLI operational steps in the correct chronological sequence required to configure authentication, transfer the image, verify file integrity, and ensure the router boots from the new image upon restart.

Drag items to arrange them in the correct order

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Answer

The correct sequence is: 1) Configure global FTP credentials, 2) Initiate the FTP transfer via copy command, 3) Verify image MD5 hash integrity in flash, 4) Set the boot system variable to the new image and save the configuration.
FTP file operations in Cisco IOS require establishing user credentials first via 'ip ftp username' and 'ip ftp password'. Once configured, the file can be downloaded using the 'copy ftp:' CLI syntax. Before scheduling the system reboot, verifying MD5 hash integrity ensures file completeness. Finally, defining the 'boot system flash' parameter and saving configuration ensures the router loads the validated software image on reboot.

Step-by-Step Solution

1
Set FTP client authentication credentials in Cisco IOS global configuration.
The router specifies the username and password required by the FTP server.
FTP requires authentication before initiating control and data connections.
2
Issue the copy ftp: flash: command to download the file.
The IOS image binary file is written to local flash memory.
File transfer relies on established network reachability and active FTP authentication.
3
Run the verify /md5 CLI command on the downloaded flash file.
The computed MD5 hash string is displayed for comparison against the release hash.
Verifying checksum integrity prevents attempting to boot from a corrupt or truncated image.
4
Configure the 'boot system flash' directive and write the running config to startup config.
The startup-config contains the instruction for ROMMON/IOS to boot the new image.
Specifying the boot target and saving configuration ensures seamless upgrade upon the next device reload.

Key Concept

FTP file transfer operation sequence for Cisco IOS system image management and boot procedure configuration.
Question 8Question →

A network engineer is transferring a 450 MB Cisco IOS XE system image across a high-latency WAN connection to a branch router. Initial transfer attempts using TFTP fail due to frequent timeouts and poor throughput over the lossy link. The engineer switches the process to use FTP, and the image file transfers completely without error. Which operational characteristic of FTP explains why it succeeds over high-latency, lossy connections where TFTP fails?

Show answer & explanation

Answer: FTP operates over TCP, leveraging sliding windows and sliding sequence acknowledgments for reliable flow control and packet loss recovery.

Answer

FTP operates over TCP, leveraging sliding windows and sliding sequence acknowledgments for reliable flow control and packet loss recovery.
The option identifying FTP's use of TCP sliding windows and acknowledgments is correct. FTP uses TCP as its transport protocol, which provides full reliability mechanisms including sequence numbering, windowing, and selective/cumulative retransmissions. This allows FTP to efficiently handle packet drops and latency over WAN links without timing out the overall session.

Step-by-Step Solution

1
Analyze transport protocol mechanics for TFTP and FTP.
TFTP operates over UDP port 69 and uses lockstep acknowledgment (each block must be individually acknowledged before the next is sent). FTP operates over TCP (ports 20 and 21) and uses connection-oriented dynamics.
Transport layer mechanisms dictate file transfer behavior over lossy or delayed networks.
2
Evaluate impact of high latency and packet loss on lockstep vs windowed transfers.
On high-latency links with loss, TFTP lockstep acknowledgments experience severe throughput degradation and frequent timeouts. FTP's TCP windowing and dynamic retransmissions recover lost segments seamlessly.
TCP sliding windows allow multiple unacknowledged packets in transit, maximizing bandwidth utilization.

Key Concept

Operational characteristics and transport mechanics of TFTP vs FTP file transfers
Question 9Question →

A network administrator needs to back up a Cisco IOS router's running configuration to a remote FTP server at IP address 10.1.1.50 using the username 'admin' and password 'Cisco123'. Which command correctly completes this file transfer in a single step?

Show answer & explanation

Answer: copy running-config ftp://admin:[email protected]/running-config.cfg

Answer

The command 'copy running-config ftp://admin:[email protected]/running-config.cfg' correctly backs up the running configuration using FTP with inline credentials.
The correct command follows the Cisco IOS convention 'copy source destination' and properly formats the FTP URL with inline authentication credentials as 'ftp://username:password@ip_address/filename'.

Step-by-Step Solution

1
Identify the source and destination for the Cisco IOS copy operation.
Source is 'running-config' and destination is the remote FTP server.
Cisco IOS uses the syntax 'copy <source> <destination>'.
2
Format the FTP URL protocol string with authentication credentials.
URL string structured as 'ftp://admin:[email protected]/running-config.cfg'.
FTP requires user authentication; Cisco IOS supports inline URL authentication using the 'ftp://username:password@host/filepath' format.

Key Concept

Cisco IOS copy command syntax and FTP URL format with authentication
Question 10Question →

A network administrator is evaluating network file transfer protocols to manage router software images and configuration backups across an enterprise network. Which TWO statements correctly describe operational differences between TFTP and FTP in a Cisco IOS environment?

Select all that apply

Show answer & explanation

Answer: TFTP operates over UDP port 69 without user authentication, whereas FTP uses TCP ports 20 and 21 and supports username/password authentication.; FTP leverages TCP windowing and sequencing for reliable transfer over variable-latency links, whereas TFTP uses a lock-step stop-and-wait acknowledgment mechanism over UDP.

Answer

The two correct statements are that TFTP operates over UDP port 69 without authentication while FTP uses TCP ports 20 and 21 with authentication support, and that FTP leverages TCP windowing for reliable transfer while TFTP relies on a stop-and-wait acknowledgment mechanism over UDP.
The statements highlighting that TFTP operates unauthenticated over UDP port 69 while FTP uses TCP ports 20/21 with authentication, and that FTP employs TCP windowing while TFTP employs lock-step stop-and-wait acknowledgments, correctly identify the fundamental transport, security, and flow control differences between the two protocols.

Step-by-Step Solution

1
Analyze transport layer protocol and port usage for both TFTP and FTP
TFTP uses UDP port 69. FTP uses TCP port 21 for control connection setup and TCP port 20 for active data connection transfer.
Understanding transport protocol assignment is fundamental to network file management.
2
Evaluate authentication mechanisms for both protocols
TFTP lacks authentication features completely. FTP requires or explicitly negotiates user credentials (username and password).
Security and access control capabilities differentiate basic file transfer protocols from authenticated management protocols.
3
Evaluate data delivery mechanics and windowing behavior
TFTP uses a lock-step (stop-and-wait) block acknowledgment scheme over UDP. FTP uses TCP flow control and windowing for dynamic bandwidth utilization.
Flow control mechanics dictate protocol performance and reliability characteristics over WAN connections.

Key Concept

Operational differences between TFTP (UDP 69, unauthenticated, lock-step) and FTP (TCP 20/21, authenticated, windowed flow control) in network management.