Troubleshooting guide

REVIEW DRAFT—CISCO CONFIDENTIAL
1-7
Cisco Wide Area Application Services Configuration Guide
OL-26579-01
Chapter 1 Introduction to Cisco WAAS
Benefits of Cisco WAAS
contains application proxies that can respond to messages locally so that the client does not have to
wait for a response from the remote server. The application proxies use a variety of techniques
including caching, command batching, prediction, and resource prefetch to decrease the response
time of remote applications.
• CIFS caching—Allows a WAAS device to reply to client requests using locally cached data instead
of retrieving this data from remote file and application servers.
• Preposition—Allows a WAAS device to prefetch resource data and metadata in anticipation of a
future client request. (Only the CIFS accelerator supports prepositioning.)
Cisco WAAS uses application-intelligent software modules to apply these acceleration features.
In a typical Common Internet File System (CIFS) application use case, the client sends a large number
of synchronous requests that require the client to wait for a response before sending the next request.
Compressing the data over the WAN is not sufficient for acceptable response time.
For example, when you open a 5 MB Word document, about 700 CIFS requests (550 read requests plus
150 other requests) are produced. If all these requests are sent over a 100 ms round-trip WAN, the
response time is at least 70 seconds (700 x 0.1 seconds).
WAAS application acceleration minimizes the synchronous effect of the CIFS protocol, which reduces
application response time. Each WAAS device uses optimization policies to match specific types of the
traffic to an application and to determine whether that application traffic should be optimized and
accelerated.
The following WAAS application accelerators are available:
• SMB—Accelerates CIFS traffic exchanged with a remote file server. Supports the SMB 1.0, 2.0, and
2.1 protocols for CIFS traffic and signed SMB traffic. For more information, see the “File Services
for Desktop Applications” section on page 1-8.
• CIFS—Accelerates CIFS traffic exchanged with a remote file server. Supports the SMB 1.0 protocol
for CIFS traffic. For more information, see the “File Services for Desktop Applications” section on
page 1-8.
Note The SMB and CIFS application accelerators both handle CIFS traffic but have slightly different
features. You must choose one or the other to operate on WAAS peer devices because they
cannot operate simultaneously on the same device and both peers must use the same accelerator.
• NFS—Accelerates Network File System (NFS) version 3 traffic exchanged with a remote file server.
Secure NFS traffic is not accelerated.
• ICA—Accelerates Independent Computing Architecture (ICA) traffic that is used to access a virtual
desktop infrastructure (VDI).
• HTTP—Accelerates HTTP and HTTPS traffic.
• SSL—Accelerates encrypted Secure Sockets Layer (SSL) and Transport Layer Security (TLS)
traffic. The SSL accelerator provides traffic encryption and decryption within WAAS to enable
end-to-end traffic optimization. The SSL accelerator also provides secure management of the
encryption certificates and keys.
• MAPI—Accelerates Microsoft Outlook Exchange traffic that uses the Messaging Application
Programming Interface (MAPI) protocol. Microsoft Outlook 2000–2010 clients are supported.
Secure connections that use message authentication (signing) or encryption are accelerated. MAPI
over HTTP is not accelerated.