Introduction

Deploying WAN optimization in an enterprise network is similar to deploying other enterprise networking technologies (for example, firewalls). There are, however, a few tenets to keep in mind:

1	Silver Peak appliances need to have visibility into any traffic that requires optimization.

As such, all traffic to be optimized must flow though the appliances. There are three ways to accomplish this:

Server mode [default]	In this default configuration, the management path and the datapath both use the same interface and the same IP address.
Bridge mode [in-line]	Silver Peak appliances are deployed as a “bump in a wire” in between the LAN infrastructure and the WAN router.
Router mode [out-of-path]	Silver Peak appliances are deployed in “one-armed” (or “lollipop”) fashion with a single connection to the WAN router. A redirection method (such as PBR or WCCP) is used to redirect traffic to the appliance.

2	Silver Peak WAN acceleration is a “symmetric” solution. That is, to optimize the traffic on the link, Silver Peak appliances are required on both ends of the WAN link.

3

Silver Peak’s Network Acceleration functions require that the appliances have visibility into both the transmit and receive directions of a flow. If not, the flow is considered “asymmetric” and Network Acceleration will be defeated although Network Integrity and Network Memory will continue to provide benefit.

Definition of Terms

Following are the definitions for common terms used throughout the guide, listed alphabetically:

Term	Definition
Acceleration	Refers to techniques used to improve transmission of TCP protocols across a WAN.  a TCP Proxy session is created to reduce the impact of latency on a TCP flow. Techniques such as local acknowledgements and window sizing are used to accelerate TCP traffic.
Auto Optimized Traffic	IP traffic that is automatically recognized by the Silver Peak appliances and optimized accordingly, without the need for manually created Route Policies. This is the default entry for the Route Policy if no entries are made, or for the last line in the route map.
Bypass	Bypass refers to hardware bypass. If there is a major problem with the appliance hardware, software, or power, all traffic goes through the appliance without any processing. Bypass mode can be enabled manually. Silver Peak appliances can be installed in the data path (in-line) between an L2/L3 switch and the edge WAN router, with fail-to-wire in case of failure.   Bypass mode and Hardware Bypass both refer to the failover method, which is Fail-to-Wire for copper interfaces, and Fail-to-Glass for fiber interfaces.
Data Path IP Address	Generally, an IP address of an interface through which end-device traffic flows or to which it is redirected. • If the device is out-of-path in Server mode, the data path and management path IPs are the same. • In Router mode, with an out-of-band management interface, the management IP and Data Path address are different. • In Bridge mode, the Data Path IP is separate from the management IP. In some deployments—like DHRM (Dual Home Router Mode) or multiple VLANS — there could be multiple data path IP addresses.
Failover or Fail-Safe Behavior	Actions taken to minimize exposure when a network element fails. Fails-to-Wire / Fails-to-Glass: Fail-to-wire network interfaces [for copper] and fail-to-glass interfaces [for 1GB fiber only] mechanically isolate the appliances from the network in the event of a hardware, software, or power failure. This ensures that all traffic bypasses the failed appliance and maximizes up-time. Fails-Open: When configured to “fail open”, a failed appliance presents no link-level carrier to the network. Routers and other network elements will route around the failed appliance by using a routing protocol (i.e., RIP, OSPF, BGP, EIGRP).
Network MemoryTM	Silver Peak's innovative approach to data reduction that leverages advanced pattern recognition and local information
Optimization	A collection of techniques that accelerate, compress, and improve the efficiency of transmission of data across a WAN. Optimization includes acceleration techniques, data reduction, forward error correction, packet order correction, QoS, and other techniques.
Pass-through Traffic	By default, traffic that is not directed to a tunnel by the Route Policy passes transparently through the Silver Peak appliance. Pass-through traffic can be either shaped or unshaped.
Route Policy	Uses MATCH criteria to delineate flows and SET actions to specify how to handle that flow. For example, a Route Policy entry would direct a specific flow to a designated tunnel.
Tunnel	Provide virtual point-to-point links between two application acceleration devices. They work by wrapping original packets of data inside an outer IP header, which is used to specify the address of the device on the far end of the WAN link.
Tunnelized Traffic	Data that is inside of a tunnel

 

Please send comments or suggestions regarding user documentation to techpubs@silver-peak.com.