Parallel NFS (pNFS) extends Network File System version 4 (NFSv4) to allow clients to directly access file data on the storage used by the NFSv4 server. This ability to bypass the server for data access can increase both performance and parallelism@ but requires additional client functionality for data access@ some of which is dependent on the class of storage used@ a.k.a. the Layout Type. The main pNFS operations and data types in NFSv4 Minor version 1 specify a layouttype- independent layer; layout-type-specific information is conveyed using opaque data structures whose internal structure is further defined by the particular layout type specification. This document specifies the NFSv4.1 Object-Based pNFS Layout Type as a companion to the main NFSv4 Minor version 1 specification.