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ACE Upgrade to A5(2.2) and Higher Causes URL-based Load Balancing

Document ID: 116328

Updated: Aug 22, 2013

Contributed by Alex Rickard, Cisco TAC Engineer.

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Introduction

This document describes how to identify and resolve a problem that occurs when the Application Control Engine (ACE) has been upgraded to release version A5(2.2) or later and URL-based load balancing fails.

Problem

The ACE has been upgraded to release version A5(2.2) from an earlier software version. After the upgrade to version A5(2.2), the ACE resets the connection for URLs that contain RFC2396 non-compliant characters, when configured for URL match based load balancing. ACE reports "Static parse errors" in the "show stats http" output.

Solution

In software version A5(2.2) as a result of the Cisco Bug ID CSCud39381, the default behavior of the ACE is to conform to RFC2396 for URL match based load balancing.

In order to allow the ACE HTTP parser to accommodate non-compliant RFC2396 characters, configure a parameter map of type HTTP which allows non-strict parsing. Next, apply this parameter map to the appropriate policy/class-map.

The format of HTTP parameter map is:

parameter-map type http <NAME>
  parsing non-strict

Note: In software release versions A5(2.0) and later, with the exclusion of release A5(2.2), the ACE HTTP parser accepted ASCII characters in the range of 32 - 126 and 128 - 255.

Note: In software release versions earlier than release A5(2.0), the ACE HTTP parser accepted ASCII characters only in the range 32 - 126.

Updated: Aug 22, 2013
Document ID: 116328