Not sure what redundancy you are talking about with GE/AS number. However 2821 has two integrated 10/100/1000 ethernet port, definately you can have two ethernet connection to 2821, and you can configure dynamic routing protocol to support routing redundancy. you can also configure HSRP with another router to provide redundancy. there is a built in external power-supply connector that eases the addition of external redundant power supply that can be shared with other Cisco products to decrease network downtime by protecting the network components from downtime due to power failures
