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DRE Cache Optimizations in 4.1.1.

What architectural changes were made to improve and optimize the DRE cache from 4.0.0 to 4.1.1? What problems were the improvements to the DRE cache addressing?


Re: DRE Cache Optimizations in 4.1.1.

HI Dear,

The DRE cache doesn't have a utility for defragmentation. The database has been improved and optimized over the life of the product to reduce the necessity for this. For catastrophic failures however, the database/cache can be deleted and repopulated with new traffic if needed.

The DRE cache will be preserved during a software upgrade.

TAC reports that for an upgrade from 4.0.17 to 4.1.1c the DRE cache is preserved.

Kindly let me know exactly which version you are looking for.

Hope that helps,



New Member

Re: DRE Cache Optimizations in 4.1.1.

What type of database does DRE use? Mysql or something like that?

Re: DRE Cache Optimizations in 4.1.1.

HI Dear,

DRE is an advanced form of network compression that allows Cisco WAAS to maintain a database of data that has been seen previously traversing the network. This information is used to remove redundant transmission patterns from the network. For repeated patterns, only instructions need to be sent, and the original message is rebuilt in its entirety by the distant Cisco WAE, providing significant levels of compression and ensuring message and application coherency because the original message is always rebuilt and verified by the distant Cisco WAE. Because DRE is application-independent and bidirectional, it is effective regardless of the application being used or direction of traffic flow. Therefore, data patterns that are identified for one application protocol can be used by other applications, and patterns that are identified for one direction of traffic flow can be used to remove redundancy for traffic flowing in a different direction. The Citrix ICA protocol does not eliminate redundant data, meaning that when a user requests previously viewed screen content the whole set of data is resent. With DRE, viewed screen content is stored as previously seen transmissions in an application-independent format, and if redundant segments are seen (that is, content or part of content that has been viewed before), significant levels of compression can be achieved. Data redundancy is especially beneficial when many Citrix ICA sessions are running concurrently over WAN links and when users are viewing content or parts of content that they have viewed before. DRE can eliminate up to 99% of redundant network traffic and provide up to 100:1 compression.



Re: DRE Cache Optimizations in 4.1.1.

HI Dear,

It is Cisco WAFS Central Manager database.

WAFS) stands for Wide Area File Services

Wide-area file services (WAFS) is a storage technology that makes it possible to access a remote data center across a wide area network (WAN) as though it were local. WAN optimization and file access acceleration are essential elements of WAFS. Caching is used to reduce WAN congestion and disruption.

WAFS enables businesses, academic institutions, and government agencies with numerous branch offices to centrally manage data backups in real time. Other benefits include immediate, round-the-clock read-write access to backed-up data for all end users in the network, low latency and rapid data transfer speed comparable to local area network (LAN) technologies, continuous real-time updating of backup content, enhanced data security and simple, rapid system recovery in the event the network is compromised or damaged. Backing up data on servers at different physical locations increases security.

Wide area file services (WAFS) products allow remote office users to access and share files globally at LAN speeds over the WAN. Distributed enterprises that deploy WAFS solutions are able to consolidate storage to corporate datacenters, eliminating the need to back up and manage data that previously resided in their remote offices. WAFS uses techniques such as CIFS and MAPI protocol optimization, data compression, and sometimes storing recurrent data patterns in a local cache.

WAFS is a subset of WAN optimization, which also caches SSL Intranet and ASP applications and elearning multimedia traffic as well, to accelerate a greater percentage of WAN traffic.

The term was coined by Brad O'Neill of the analyst firm Taneja Group in a May 2004 article for InfoStor magazine

The term WAFS is used generically. Vendors have different names for their technologies. Here's how Stephen J. Bigelow has broken it down:

Riverbed Technology Inc. uses the term wide-area data services (WDS or WADS) to include WAFS along with a richer set of WAN optimization and file access features. Cisco Systems Inc. uses wide-area application services (WAAS), which is also more comprehensive and feature rich than WAFS. Brocade Communications Systems Inc. uses the term file area network (FAN) to refer to a collection of remote file management and access technologies. The term wide-area data management (WADM) has also recently appeared.

WAN optimization appliances have traditionally limited IT when it comes to maintaining functions such as security, QoS, visibility, and monitoring end-to-end transactions because they tend to cause problems for most network monitoring devices and tools. By design, WAN Optimization “confuses” performance monitoring systems by changing packet header data

SOme Important links in htis regard:

1. Release Notes

2. Introduction

WAFS command reference:

Still your question is unanswered. I need some time to do a research for the exact type of the database. Kindly allocate me some time to give you appropriate answere. In betweeen you cna refer the above mentioned links if you like.

Kind Regards,


New Member

Re: DRE Cache Optimizations in 4.1.1.

Thanks. I am very familiar with WAFS and WAAS. I have deployed them since 4.0.1. I am just curious what technical changes have been made concerning DRE since the 4.1.1 upgrade.


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