Riverbed® Steelhead® RiOS® Application Installation and Getting Started Guide 2010-10

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Overview
Accelerating WAN Connections
Deployment
The Riverbed Steelhead appliance and the Extended Services zl Module with
Steelhead Application are deployed differently. The Steelhead appliance is
deployed inline, while the Extended Services zl Module with Steelhead Appli-
cation is deployed in an HP 5400zl or 8200zl Switch Series.
Inline Deployment
In Figure 1-1, the Steelhead appliance at the main office has been deployed in-
line between a switch and a firewall. The Steelhead appliance has two ports,
port-1 and port-2. Port-1 is connected to the switch, and port-2 is connected
to the firewall. The appliance will receive all the traffic that is sent from the
switch to the firewall as well as any traffic sent from the firewall to the switch.
Steelhead appliances rely on the Riverbed Optimization System (RiOS) to
intercept client-server connections without interfering with normal client-
server operations, file semantics, or protocols. All client requests are passed
through to their destination (such as a network server) normally, while
relevant traffic is optimized to improve performance.
Switch-Based Deployment
Rather than being deployed inline, the Extended Services zl Module with
Steelhead Application provides WAN acceleration inside a network switch.
Because the Steelhead application integrates seamlessly with the HP 5400zl
or 8200zl switch and the Extended Services zl Module, it relies on the HP
switch to identify and redirect the traffic that you want to accelerate.
The HP switches use a technology called Transparent Mode to intercept
packets that match certain criteria and redirect them to the Steelhead Appli-
cation that is running on the Extended Services zl Module. For the selected
traffic, Transparent Mode allows the Steelhead Application to be in the path
of packet flow.
It is important to differentiate in-path packet interception from port mirror-
ing. With port mirroring, the switch copies the packets being sent from a
specified source port to a specified destination port and then sends these
copied packets to a mirror port. The original packets continue to be sent from
the source port to the destination port, without interruption.
With packet interception, on the other hand, the HP 5400zl or 8200zl switch
does not copy packets to another port. Instead the switch actually intercepts
the packets and sends them to the Steelhead Application, which then acceler-
ates the delivery of the packets to their final destination. After intercepting