Let's see, these Ethernet switches support 100/1000 Base-T gigabit, which means the signal travels point-to-point over twisted pairs at speeds of either 100 million bits per second, or 1000 million bits per second. This is much faster than Redbook Compact Disk needs which is about 1.4 million bits per second.
Please note carefully that Ethernet is not slowed down to match the audio rate! Instead the audio stream is chopped into packets up to 12,000 bits long (Gigabit can have non-standard longer packets if both ends agree!). This means there is much more silence on an Ethernet Link than signal, punctuated by very short bursts of signal.
Each packet starts with a preamble, then the address of the sender and intended receiver (these are the Media Access Code or MAC addresses and are globally unique). Finally, there is a cyclic redundancy check which allows corrupted packets to be detected.
The preamble is 56 bits alternating between 0 and 1 which allows the receiver to match the clock rate of the sender.
When the receiver has to turn the packets into an audio signal, it has to assemble the incoming packets into a memory buffer, and then clock them out at a much slower rate which has nothing to do with the clock rate of the Ethernet!
Ethernet is essentially a broadcast technology, so all a connection box needs to do is listen to any transmission and broadcast it on all other connections. This is what an Ethernet Repeater does. An Ethernet Switch is slightly smarter - it looks at the MAC addresses in each packet and works out which physical cable connects to each address. Then it only has to forward a packet down one cable (OK there is an exception for a broadcast message where the receiving address stands for all addresses).
My conclusion: jitter in an Ethernet switch is inconsequential because the audio stream has to be re-clocked from a memory buffer anyway. Errors in the digital payload are always detectable. If you can hear a difference between switches, be suspicious of the EMI they are generating which affects your other components.
