The Raspberry Pi Zero does not come with an ethernet port. For my experimental router project, I need to connect the Pi Zero to a wired network where the Pi Zero will act as a router for many computers. I can use a USB to RJ45 adapter for this task, but I may need something faster. What is the cheapest way to achieve high speed ethernet connections?
To summarize the comments in an answer: if you want real gigabit throughput you cannot use any Raspberry Pi. The RPi Zero is the worst candidate. 10Mb would be more realistic. Raspberry Pi USB's are USB2.0. USB2.0 has an absolute theoretical maximum speed of 480Mbit - though, in reality you'd be lucky to get 300Mbit - and I dare say that would be half duplex - about one sixth of what you would want for gigabit ethernet. You may look at using the new Pi 3B+ which comes with Gigabit Ethernet over USB 2.0 (maximum throughput 300 Mbps).
Cited from the comments of @Milliways, @Jaromanda X, @HeatfanJohn, thanks.
An old post but being that I am working on throughput on our network at the moment and found this, I thought I would toss in my real world experience. Been running a Raspberry pi zero for about 4 years now as a NAS/Backup NAS. The unit had actually run for over 3 years without rebooting before the main shop was rebuilt. The pi zero real world, using a gigabit USB adapter and powered USB HDD;
- iperf3 (send and receive) ~130mbit (~16.25MB)
- rsync transfer from Main NAS 4.8 - 5.5MB per second (38.4 - 44mbit)
- PC to PC iperf3 is ~940bit - 980mbit (~117.5MB - ~122.5MB)
Previously we used a RPI 3B+ as a router firewall. It worked good but was not able to keep up with the throughput required once we went above 500mbit internet. We've been using a Ubiquiti EdgeRouter X for a few years now with probably a dozen or two installed at client sites (we're a security company with it background). For ~$100CND (a lot cheaper in the US), these are probably the best routers for the $$ we have found. They are Linux based with a CLI so you can do a ton of back end programming. We were able to move our configurations over from the rpi to our unit with little issues. In all honesty, an edgerouter x would be more cost effective than going with a new pi 4 with all the accessories.