Could someone explain to me simply what is the difference between SONET and T-Carrier?
I know that the ISP generally uses SONET on their infrastructure (Ciscopress 2017, 1.2.1.2 section, http://www.ciscopress.com/articles/article.asp?p=2832405&seqNum=5), but we could often see that the leased lines offered by the ISP mentioning E1 or T1 are referred to as T-Carrier. So I'm a little bit confused.
Also, as the E1 and T1 line provides a dedicated bandwidth, does the ISP guarantee, like the E1 and T1 lines, a minimum bandwidth with IP/MPLS or VPLS?