The proxy uses the OtherInformation definition to carry information about the target address and cookie.

  OtherInformation   ::= [201] IMPLICIT SEQUENCE OF SEQUENCE{
    category           [1]   IMPLICIT InfoCategory OPTIONAL, 
    information        CHOICE{
      characterInfo            [2]  IMPLICIT InternationalString,
      binaryInfo               [3]  IMPLICIT OCTET STRING,
      externallyDefinedInfo    [4]  IMPLICIT EXTERNAL,
      oid                      [5]  IMPLICIT OBJECT IDENTIFIER}}
--
  InfoCategory ::= SEQUENCE{
      categoryTypeId   [1]   IMPLICIT OBJECT IDENTIFIER OPTIONAL,
      categoryValue    [2]   IMPLICIT INTEGER}
  

The categoryTypeId is either OID 1.2.840.10003.10.1000.81.1, 1.2.840.10003.10.1000.81.2 for proxy target and proxy cookie respectively. The categoryValue is set to 1. The value proxy and cookie is stored in element characterInfo of the information choice.