Cisco is an US company which provide knowledge about networking devices such as router and switches and it is also a good vendor for routers and switches. Cisco.com is the website of cisco where deep knowledge about networking is available.
Service and support is very good because if anyone buy cisco routers and switches, and any problem comes on that device then they provide a good service and support.
At this website very very deep knowledge is available related to networking.
Cisco organise certification program for certified network engineer and programs are CCNA, CCNP, CCIE. All the content of this exams are available at this website.
Design of this website is very good.
Website load time is very shot and response is very good.