Troubleshooting guide

REVIEW DRAFT—CISCO CONFIDENTIAL
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Cisco Wide Area Application Services Configuration Guide
OL-26579-01
Chapter 1 Introduction to Cisco WAAS
Benefits of Cisco WAAS
• Prepositioning—Allows system administrators to proactively “push” frequently used files from the
central file server into the cache of selected WAEs, which provides users with faster first-time file
access, and makes more efficient use of available bandwidth. Prepositioning is supported only by
the CIFS application accelerator.
Role of the Edge WAE
The Edge WAE is a client-side, file-caching device that serves client requests at remote sites and branch
offices. The device is deployed at each branch office or remote campus, replacing file and print servers
and giving local clients fast, near-LAN read and write access to a cached view of the centralized storage.
By caching the data most likely to be used at these sites, Edge WAEs greatly reduce the number of
requests and the volume of data that must be transferred over the WAN between the data center and the
edge.
When requests for data that is not located in the cache are received, the Edge WAE encapsulates the
original CIFS request using a TCP/IP-based protocol, compresses it, and sends it over the WAN to the
Core WAE. Data returned from the data center is distributed by the Edge WAE to the end user who
requested it.
Role of the Core WAE
The Core WAE is a server-side component that resides at the data center and connects directly to one or
more file servers or network-attached storage (NAS). Core WAEs are placed between the file servers at
the data center and the WAN connecting the data center to the enterprise’s remote sites and branch
offices. Requests received from Edge WAEs over the WAN are translated by the Core WAE into its
original file server protocol and forwarded to the appropriate file server. The data center Core WAEs can
provide load balancing and failover support.
When the data is received from the file server, the Core WAE encapsulates and compresses it before
sending it over the WAN back to the Edge WAE that requested it. Core WAEs can be arranged in logical
clusters to provide scalability and automatic failover capabilities for high-availability environments.
WAAS Print Services
The WAAS software includes the following print services options:
• Windows print accelerator—Use this option when you have a print server in a data center and branch
clients are printing to local or remote printers. This service accelerates print traffic between clients
and a Windows print server located in the data center. This option requires no configuration but does
require that both the CIFS application accelerator and Windows print acceleration be enabled. For
more information, see the “Enabling and Disabling the Global Optimization Features” section on
page 1-3.
• Virtual blade based print server—Use this option when you want to deploy a local print server in the
branch office but without installing separate print server hardware. You can install a Windows print
server in a virtual blade on the branch WAE, which allows you to manage printing by using standard
Windows print server functionality. For more information, see Chapter 1, “Configuring Virtual
Blades.”
Note The legacy print services feature is no longer supported. Legacy print services users must
migrate to another print services option.