Complex sentence: Both PVST and PVST + protocols are Cisco proprietary protocols and they cannot be used on most 3rd party switches, although Brocade supports PVST and Force10 Networks, Extreme Networks, and Blade Network Technologies support PVST +.
Split into simpler sentences: Both PVST and PVST + protocols are Cisco proprietary protocols and they cannot be used on most 3rd party switches. Some equipment from Force10 Networks, Extreme Networks, and Blade Network Technologies support PVST +.