Troubleshooting guide

1-24
Cisco Wide Area Application Services Configuration Guide
OL-26579-01
Chapter 1 Planning Your WAAS Network
Supported Methods of Traffic Redirection
By default, the IP Protocol 6 is specified for the TCP promiscuous mode service. Consequently, the
routers that have been configured to the TCP promiscuous mode service will intercept and redirect all
TCP traffic destined for any TCP port to the local WAE. Because the TCP promiscuous mode service is
configured on the WAE, the WAE will accept all of the TCP traffic that is transparently redirected to it
by specified WCCP routers (for example, Edge-WAE1 will accept all TCP traffic that Edge-Router1
redirects to it). In the branch office, you can intercept packets at the edge LAN and WAN interfaces on
the edge routers and redirect the TCP traffic to the local WAE (the branch WAE). In the data center, you
can intercept packets at the core LAN and WAN interfaces on the core routers and redirect the TCP
traffic to the local WAE (the data center WAE). For more information, see the “Configuring WAEs as
Promiscuous TCP Devices in a WAAS Network” section on page 1-24.
Configure packet redirection on inbound interfaces of branch software routers whenever possible.
Inbound traffic can be configured to use Cisco Express Forwarding (CEF), distributed Cisco Express
Forwarding (dCEF), fast forwarding, or process forwarding.
Note CEF is required for WCCP and must be enabled on the router.
To enable packet redirection on a router’s outbound or inbound interface using WCCP, use the ip wccp
redirect interface configuration command.
Caution The ip wccp redirect interface command has the potential to affect the ip wccp redirect exclude in
command. If you have ip wccp redirect exclude in set on an interface and you subsequently configure
the ip wccp redirect in command, the exclude in command is overridden. If you configure the exclude
in command, the redirect in command is overridden.
This section contains the following topics:
• Configuring WAEs as Promiscuous TCP Devices in a WAAS Network, page 1-24
• Using Tertiary Interfaces or Subinterfaces to Connect WAEs to Routers, page 1-24
Configuring WAEs as Promiscuous TCP Devices in a WAAS Network
In order for the WAE to function as a promiscuous TCP device for the TCP traffic that is transparently
redirected to it by the specified WCCP Version 2 routers, the WAE uses WCCP Version 2 services 61
and 62 by default, though the service IDs are configurable. The WCCP services are represented by the
canonical name tcp-promiscuous on the WAE CLI and TCP Promiscuous in the WAAS Central Manager
GUI. (See Figure 1-3.)
For instructions on how to perform a basic WCCP configuration for a WAAS network, see the Cisco
Wide Area Application Services Quick Configuration Guide. For instructions about how to use the
WAAS Central Manager GUI to modify the basic WCCP configuration for a WAE, see the “Configuring
WCCP on WAEs” section on page 1-11.
Using Tertiary Interfaces or Subinterfaces to Connect WAEs to Routers
If you plan to use WCCP Version 2 or PBR to transparently redirect TCP traffic to a WAE, make sure
that the WAE is not attached to the same segment as the router interface on which the traffic redirection
is to occur. Otherwise, an infinite routing loop between the router and the WAE will occur. These infinite
routing loops occur because there is no way to notify the router to bypass the interception and redirection
after it has redirected the traffic to the WAE the first time; the router will continuously redirect the same
intercepted traffic to the local WAE, creating the infinite routing loop.