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Cisco AVVID Network Infrastructure Enterprise Quality of Service Design
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Chapter 1 Overview
Why is Quality of Service Required for AVVID?
Relative Priority vs. Over-Engineering Bandwidth Provisioning
Because bandwidth requirements vary greatly from application to application (and even between
versions of the same applications) it is not possible to provide a blanket rule for provisioning data
bandwidth. Traffic analysis and lab-testing are required to ascertain bandwidth requirements for data
applications.
shows a comparison of traffic patterns between two popular mission-critical ERP
applications, Oracle and SAP.
Figure 1-4
Oracle versus SAP R/3 Packet Distribution
In addition to the wide variation of traffic patterns and requirements between different data applications,
traffic patterns often vary greatly between two versions of the same application.
illustrates a
situation where the same transaction in one version of SAP requires 35 times more bytes than an earlier
version.
Figure 1-5
SAP Version Traffic Comparison for Identical Transactions
The following is an example of basic bandwidth provisioning for data.
An enterprise has as SAP R/3 as its mission-critical application. The task most typically performed by
users in the remote offices is the Create Sales Order transaction (VA01). This transaction entails 14 KB
of data, which translates to 112 kbps of required bandwidth to ensure a response time of less than 1
second. If SAP is provisioned as a mission-critical application receiving 25% of the link's capacity, then
a link size of approximately 512 kbps is required to provide this service-level.
Oracle
SAP
74639
0-64 Bytes
1024-1518 Bytes
512-1023 Bytes
253-511 Bytes
65-127 Bytes
128-252 Bytes
253-511 Bytes
512-1023 Bytes
1024-1518 Bytes
128-252 Bytes
65-127 Bytes
0-64 Bytes
74640
SAP GUI,
Release
3.0F
500,000
400,000
300,000
200,000
100,000
0
SAP GUI,
Release
4.6C,
with Cache
Bytes per Sales Order Entry (VA01)
Transaction
SAP GUI,
Release
4.6C,
no Cache
SAP GUI
(HTML),
Release
4.6C