The Carlson SAN mixes equipment from a number of vendors.What problems does this raise and what are some management options for dealing with them?

Carlson Companies is one of the largest privately held companies in the United States, with more than 180,000 employees in more than 140 countries. Carlson enterprises include a presence in marketing, business and leisure travel, and hospitality industries.
Its Information Technology (IT) division, Carlson Shared Services, acts as a service provider to its internal clients and consequently must support a spectrum of user applications and services. The IT division uses a centralized data processing model to meet business operational requirements. The central computing environment includes an IBM mainframe and over 50 networked Hewlett-Packard and Sun servers [KRAN04, CLAR02, HIGG02]. The mainframe supports a wide range of applications, including Oracle financial database, e-mail, Microsoft Exchange,Web, PeopleSoft, and a data warehouse application.