A CloudBridge appliance acts as a virtual gateway. It is neither a TCP endpoint nor a router. Like any gateway, its job is to buffer incoming packets and put them onto the outgoing link at the right speed. This packet forwarding can be done in different ways, such as inline mode, virtual inline mode, and WCCP mode. Although these methods are called modes, you do not have to disable one forwarding mode to enable another. If your deployment supports more than one mode, the mode that the appliance uses is determined automatically by the Ethernet and IP format of each packet.
Because the appliance supports different forwarding modes and different kinds of non-forwarded connections, it needs a way of distinguishing one kind of traffic from another. It does so by examining the destination IP address and destination Ethernet address (MAC address), as shown in table below. For example, in inline mode, the appliance is acting as a bridge. Unlike other traffic, bridged packets are addressed to a system beyond the appliance, not to the appliance itself. The address fields contain neither the appliance's IP address nor the appliance's Ethernet MAC address.
In addition to pure forwarding modes, the appliance has to account for additional types of connections, including management connections to the GUI and the heartbeat signal that passes between members of a high-availability pair. For completeness, these additional traffic modes are also listed in table below.
|Destination IP Address||Destination Ethernet Address||Mode|
|Not appliance||Not appliance||Inline or Pass-through|
|Not appliance||Appliance||Virtual Inline or L2 WCCP|
|Appliance||Appliance||Direct (UI access)|
|Appliance (VIP)||Appliance||High-Availability. Proxy mode|
|Appliance (WCCP GRE Packet)||Appliance||WCCP GRE Mode|
|Appliance (Signaling IP)||Appliance||Signaling Connection (CloudBridge plugin Signaling Connection (CloudBridge plugin, Secure Peer) or Redirector Mode Connection (CloudBridge plugin)|
|All modes can be active simultaneously. The mode used for a given packet is determined by the Ethernet and IP headers.|