No, as I understand it, the network does not need to be transmitted. The decoder learns on the same stream as the encoder, so you do not need to transmit network parameters.
https://news.ycombinator.com/item?id=27244810
it's a very clever use of symmetry.
LZ78 used it "just" to build a dictionary, but the general idea of using symmetry is there.
(A fascinating variant on this is Semantic Dictionary Encoding, by Dr Michael Franz in his doctoral dissertation (1994), that used this symmetry to compress partial ASTs to cache partially generated code for runtime code generation)
As I understand it, when starting up (beginning of stream) - the network does not compress, then guesses the next byte at every turn determininstically from input so far.
Decoding can "read" the fist byte, then proceed to learn and guess the second byte and so on.