in its simpliest form, a virtual chassis is two or more (depening of if your talking about firewalls or switches) devices that are connected togeather and act as one logical unit.
If you're familar with Cisco its similar to a stack of switches.
Virtual Chassis is a method to make individual switches behave as if they are blades in a chassis switch matrix. The group of switches in the chassis join together into a single device (up to ten switches). They are considered a single device and you configure all of them as if they were one large switch.
The chassis fabric is created by cabling them together in a loop using the back side ports or specially configuring the uplink ports if you want them farther apart.
This fabric allows all ports in all switches to directly connect traffic without any other connections or trunking between members
Only one switch of the group runs the master routing engine.
A second switch in the group is a hot standby for the routing functions in case the first one fails.
All other switches are line card ports for use.
See these pages for a longer description of the components and configuration.
Steve Puluka BSEET Juniper Ambassador Senior Network Engineer JNCIA-ER JNCIA-EX JNCIS-SEC JNCIP-SEC JNCIS-FWV JNCIS-SSL MCP - Managing Server 2003 MCP - Windows XP Professional MCTS Windows 7 http://puluka.com/home
