Garlic routing is a variant of onion routing that encrypts multiple messages together to make it more difficult for attackers to perform traffic analysis.
Garlic routing is one of the key factors that distinguishes I2P from Tor and other privacy or encryption networks. The name comes from actual garlic, whose structure this protocol resembles. "Garlic routing" was first coined by Michael J. Freedman in Roger Dingledine's Free Haven Master's thesis Section 8.1.1 (June 2000), as derived from Onion Routing.
List of P2P applications that use garlic routing
I2P - an anonymizing overlay network which allows applications to run on top of it (open source, written in Java)