Mahesh

Strictly speaking all switches are chassis based switches. They come in two types

1) Fixed chassis switches. These are switches such as the 2950/60, 3560, 3750 where you buy the switch as a whole unit.

2) Modular switches. These are switches such as the 4500/6500. Here you buy the chassis and then you populate the chassis with separate line cards/modules. These type of switches need at least one supervisor module which is the "brains" of the switch.

Modular switches, especially the 6500, give you greater flexibility and scalability in general than fixed chassis switches but at a price.

Jon