(This is a minimal demo; production code requires timeouts, retransmits, and error handling.) | Transfer size | 512-byte blocks | 1468-byte blocks (with option) | |---------------|----------------|--------------------------------| | 1 MB | ~2000 packets | ~700 packets | | 10 MB | ~20,000 packets | ~7,000 packets |
Overhead: Each DATA packet requires an ACK (lock-step). Large block sizes dramatically improve throughput, especially on high-latency links. tftp server
(e.g., satellite): Use timeout option to adjust retransmission timer. 10. Alternatives to TFTP (When to Not Use It) | Protocol | Advantage over TFTP | |----------|---------------------| | HTTP | Auth, encryption (HTTPS), resumable, caching | | FTP | Auth, directory listing, passive mode | | SFTP/SCP | Full security, SSH tunnel | | NFS | Filesystem semantics, locking | | iSCSI | Block-level access (boot from SAN) | (This is a minimal demo; production code requires
while True: data, addr = sock.recvfrom(1024) opcode = struct.unpack('!H', data[:2])[0] if opcode == 1: # RRQ filename = data[2:].split(b'\x00')[0].decode() mode = data[2+len(filename)+1:].split(b'\x00')[0].decode() print(f"RRQ: filename (mode) from addr") # Send file in 512-byte blocks (simplified) with open(f"directory/filename", 'rb') as f: block = 1 while True: chunk = f.read(512) packet = struct.pack('!HH', 3, block) + chunk sock.sendto(packet, addr) ack, _ = sock.recvfrom(4) if struct.unpack('!H', ack[:2])[0] != 4 or \ struct.unpack('!H', ack[2:4])[0] != block: break # error if len(chunk) < 512: break block += 1 caching | | FTP | Auth