said by wayjac:
The 2wire can allow access to 253 devices
To be more precise, the 2wire can allocate 253 IP addresses, but that does NOT mean that 253 devices may concurrently browse the web. 2wire devices have a small Network Address Translation table of only 1024 sessions. Whenever a device talks to the internet, several of the NAT sessions will be tied up for some seconds or minutes, depending on the type of traffic.
1024 NAT sessions was fine 5-7 years ago, but these days a single web page request may touch a dozen servers (images, videos, tracking cookies, ads, DNS, etc.), and each server connection requires its own NAT session. Multiply that with dozens of concurrent users, and everything grinds to a halt because the 2wire is unable to keep track of all the simultaneous connections.
There is not much you can do about this 2wire limitation. Even placing another router in DMZ may not not help much, because the 2wire's DMZ implementation still tracks NAT sessions.