A "trusted source at Comcast told "Broadband Reports" (http://www.dslreports.com/shownews/Comcast-Exploring-250-Mbps-Service-10...) that before the end of the year, we'll begin hearing "rumblings" of a 250 Mbps service.

Comcast has already pushed DOCSIS 3.0 past 90% of their footprint, delivering 50 Mbps speeds in the process. While the company only offers 100 Mbps service in one market, a source told "Broadband Reports" that Comcast will be pushing faster 100 Mbps service to around 20% of their market by year's end. 250 Mbps will take a bit longer.

"We'll get there, but for many practical reasons the early DOCSIS 3.0 systems are designed for 160 meg shared down, 100 meg shared up, using four channels in each direction," industry analyst Dave Burstein told "Broadband Reports."

The DOCSIS 3.0 specification was unveiled in August 2006 when CableLabs outlined the methodology for downstream and upstream channel bonding, along with other features such as IPv6, IP multicasting and AES encryption. DOCSIS 3.0 can purportedly achieve downstream speeds of up to 160 Mbps by bonding 6 MHz channels together . DOCSIS upstream channel bonding can provide up to 120 Mbps of shared throughput for cable operators.