It's not a requirement. It's important to consider what systems your suppliers or potential suppliers already use. You have to make sure you have access to the suppliers you need access to. In a lot of cases, vendors are responding to this by developing their own supplier enablement initiative. Enablement encompasses different types of support, such as providing a wide range of prepackaged adapters to link various manufacturers' systems to the integration application or providing services that make it easier for suppliers to support a particular integration framework.
Suppliers can choose to integrate via flat-file catalog sharing or via XML or another standard.
It also provides suppliers with services such as transaction routing and transaction integration with standard financial applications, and reporting and analytical tools. It's of no use having the buyers if there aren't enough suppliers enabled and ready to transact electronically, and if the buyers cannot locate them easily. Ariba also recently released Ariba Ready, a new initiative to help buyers quickly identify trading partners that are already accessing the Ariba Commerce Services Network. It's common business wisdom to look for suppliers that are experienced at serving companies similar to your own. This is also good advice when searching for an e-procurement vendor.