Sorcerer's Apprentice syndrome

Sorcerer's Apprentice syndrome (SAS) is a network protocol flaw in the original versions of TFTP.

It was named after Goethe's 1797 poem "Der Zauberlehrling" (popularized in the US by the "Sorcerer's Apprentice" segment of the 1940 animated film Fantasia), because the details of its operation closely resemble the disaster that befalls the sorcerer's apprentice: the problem resulted in an ever-growing replication of every packet in the transfer.

If the timer expires with no reply received, it takes some action; typically re-sending the original packet.

A typical scenario was as follows: It will be seen that at this point the situation is now stable, and repeats; every packet from then on is duplicated (that is, two identical copies are sent across the internetwork).

If the file were large, however, congestive collapse would result, and only when the transfer failed would the mass of packets drain from the internetwork.