One word - money. Ethernet gear is cheaper to buy and cheaper to run.So what's the problem? Reliability and availability. The installed base of traditional SONET is huge and SONET technology has been engineered for excellent reliability and fault...
Unfortunately, Cisco does not have an true implementation of multicast-enabled MPLS available today, other than that idea where you run tunnels between various CE routers (which is basically a hack). The Internet draft standard of draft-rosen-vpn-mc...
The best literature by far that I have found to understand inter-AS and CoC topologies are papers from, uh, another vendor who is a competitor of Cisco and who therefore shall remain unnamed. The problem with stuff in Ciscopress books and even on CC...
The above answers are fine answers.But I have an even better answer - who cares? While xxxFast are not quite obsolete yet, they are now considered to be legacy, and Cisco (and the rest of the industry )has moved on to new and improved STP algorithms...
Depends on what you're doing. But in general, the extended communities and the RD will usually have to be compatible, and the address-scheme may need to be compatible also.But the real question is - why do you care? If you're just asking out of aca...