Trivial File Transfer Protocol

As explained in Acing the CCNA Exam: Volume 2 Advanced Networking and Security

Trivial File Transfer Protocol is a lightweight application-layer protocol for transferring files, typically without authentication or encryption.

Trivial File Transfer Protocol (TFTP) transfers files between a client and server with a deliberately small feature set. Its common Cisco use is moving an IOS image from a file server to a router or switch during an upgrade. section 8.0 section 8.1

Use these facts to identify TFTP behavior and exam boundaries:

• Use a client read request to download a file or a write request to upload one. section 8.1.1
• Remember UDP port 69 for the initial request; TFTP supplies reliability through lock-step exchanges rather than TCP. section 8.1.1
• Expect ordered blocks, one acknowledgment per block, timers, and retransmissions when messages or replies are lost. section 8.1.1
• Avoid public-network transfers because TFTP provides neither authentication nor encryption; use it within a controlled environment such as a LAN. section 8.1

Cisco IOS represents storage locations as file systems. The opaque type supports internal functions such as system:, disk represents physical storage such as flash:, network provides access to remote systems such as tftp:, and nvram: stores startup-config. Use show file systems to identify types and defaults, dir to inspect a location, and more to display a file. section 8.1.2 section 8.4

Copy an IOS image from TFTP to flash

SW1# copy tftp: flash: Address or name of remote host []? 192.168.1.224 Source filename []? C2960c405-universalk9-mz.152-7.E7.bin Destination filename [c2960c405-universalk9-mz.152-7.E7.bin]? Accessing tftp://192.168.1.224/C2960c405-universalk9-mz.152-7.E7.bin... [OK – 18179072 bytes] 18179072 bytes copied in 200.831 secs (90519 bytes/sec) The first prompt identifies the TFTP server, the second names the remote file, and the third supplies its local filename. Verify the result with show flash:; the new image should appear alongside the currently used image. section 8.1.2

Figure 8.1 Transferring an IOS image to a network device with TFTP. (1) Download the IOS image from Cisco’s website via HTTPS. (2) Transfer the image to the network device via TFTP.

Follow the transfer path from a secure HTTPS download to the administrator’s PC, then from that PC to the network device through TFTP. section 8.1

How Acing the CCNA Exam: Volume 2 Advanced Networking and Security covers it

How deep it goes

Explains requests, UDP port 69, lock-step blocks, acknowledgments, retransmissions, IOS file systems, and transfer commands.

Examples

Demonstrates IOS-image copying with copy tftp: flash:, then verifies storage with show flash: and inspects file systems with show file systems.

What it assumes

Assumes basic file-transfer and TCP/UDP reliability concepts while defining TFTP, IOS file systems, and storage locations explicitly.

What you can do after

Operate TFTP through Cisco IOS copy, show file systems, dir, more, and show flash: commands.

How it connects

Connects TFTP with client-server architecture, UDP, Cisco IOS file systems, IOS images, LANs, and FTP.

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Also explained in

• 

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  Acing the CCNA Exam: Volume 1 Fundamentals and ProtocolsTrivial File Transfer Protocol is a simple file-transfer protocol that provides its own acknowledgment-based reliability while using UDP.

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Related concepts

• UDPuses · UDP (User Datagram Protocol) is a connectionless transport-layer protocol that sends datagrams without guaranteeing delivery, ordering, or duplicate suppression.
• FTPcontrasts with · FTP is an application-layer network protocol for transferring files between networked systems, typically using separate control and data connections.
• lock-step communicationuses · Lock-step communication is a sequential exchange in which each message is followed by a wait for the corresponding reply before the next message is sent.
• authenticationcontrasts with · Authentication is the process of establishing or verifying the identity of a user, service, device, or other communicating entity.
• client-server architectureuses · A distributed computing pattern in which clients request services or resources from servers, which process the requests and provide results.

This explainer was generated by Manning's knowledge graph from the text of Acing the CCNA Exam: Volume 2 Advanced Networking and Security. The section links point to the parts of the book it draws on.