All networks are “lossy” because any cable can be cut, etc. A “lossy” protocol is one that doesn’t attempt to compensate for that. In most cases, but not all,

All networks are “lossy” because any cable can be cut, etc. A “lossy” protocol is one that doesn’t attempt to compensate for that. In most cases, but not all, that means a higher level protocol will need to ensure that every bit of data has made it through. (An example protocol that might not care is one for watching broadcast TV on the Internet… if you miss a few seconds it’s not a big deal).