Troubleshooting guide

1-22

Cisco Wide Area Application Services Configuration Guide

OL-26579-01

Chapter 1 Planning Your WAAS Network

Supported Methods of Traffic Redirection

Configuring WCCP or PBR Routing for WAAS Traffic

The primary function of WAAS is to accelerate WAN traffic. In general, WAAS accelerates TCP traffic.

WAAS uses a symmetric approach for application optimization. A WAE that has application-specific and

network-specific intelligence is placed on each side of the WAN. These WAEs are deployed out of the

data path in both the branch office and the data center.

Traffic between the clients in the branch offices and the servers at the data center is transparently

redirected through the WAEs based on a set of configured policies with no tunneling. The routers use

WCCP Version 2 or PBR to transparently intercept and redirect traffic to the local WAE for optimization,

redundancy elimination, and compression. For example, Edge-Router1 uses PBR or WCCP Version 2 to

transparently redirect traffic to Edge-WAE1, the local WAE in the branch office. Core-Router1 uses PBR

or WCCP Version 2 to transparently redirect traffic to the Core-WAE1, the local WAE in the data center.

Note In this sample deployment, the Edge-Router1 and Core-Router1 could be replaced with Layer 4 to Layer

7 switches, which are capable of redirecting traffic to the local WAE.

Figure 1-1 shows that the WAEs (Edge-WAE1 and Core-WAE1) must reside in an out-of-band network

that is separate from the traffic’s destination and source. For example, Edge-WAE1 is on a subnet

separate from the clients (the traffic source), and Core-WAE1 is on a subnet separate from the file servers

and application servers (the traffic destination). Additionally, you may need to use a tertiary interface (a

separate physical interface) or a subinterface to attach a WAE to the router, which redirects traffic to it,

to avoid an infinite routing loop between the WAE and the router. For more information on this topic,

see the “Using Tertiary Interfaces or Subinterfaces to Connect WAEs to Routers” section on page 1-24.

Figure 1-1 Example of Using PBR or WCCP Version 2 for Transparent Redirection of All TCP Traffic to WAEs

Table 1-1 provides a summary of the router interfaces that you must configure to use PBR or WCCP

Version 2 to transparently redirect traffic to a WAE.

Clients

159088

Edge-WAE1

1.1.1.100 2.2.2.100

PBR or

WCCP Version 2

WAN

Data center (10.10.11.0/24)

Branch office (10.10.10.0/24)

File servers

and application

servers

Core-WAE1

PBR or

WCCP Version 2

Edge-Router1

Core-Router1

WAAS Central

Manager