IPv6 is used internally a lot more than externally, so I would expect to see a LOT of commonality in the network ID fraction of the addresses- essentially all the bits of representing your IPv6 network ID get reduced to the number of bits in a compression token, in the worst case. In the moderate case, you get a few chatty machines (DNS servers and the like) where the whole address is converted to a single compression token. In the best case, you get that AND a lot of repetition in the rest of the message, and you reduce most of each message to a single compression token.
It's hard to explain if you haven't actually experimented with it, but modern variants of LZ compression are miraculous. It's like compilers- your intuition tells you hand tuned assembly is better, but compilers know crazy tricks and that intuition is almost always wrong. Same with compressors- they don't look at data the same way you do, and they work way better than your intuition thinks they would.
IPv6 is used internally a lot more than externally, so I would expect to see a LOT of commonality in the network ID fraction of the addresses- essentially all the bits of representing your IPv6 network ID get reduced to the number of bits in a compression token, in the worst case. In the moderate case, you get a few chatty machines (DNS servers and the like) where the whole address is converted to a single compression token. In the best case, you get that AND a lot of repetition in the rest of the message, and you reduce most of each message to a single compression token.
It's hard to explain if you haven't actually experimented with it, but modern variants of LZ compression are miraculous. It's like compilers- your intuition tells you hand tuned assembly is better, but compilers know crazy tricks and that intuition is almost always wrong. Same with compressors- they don't look at data the same way you do, and they work way better than your intuition thinks they would.