ize to the maxi- mum transfer unit (MTU) of the local network. Fundamentals of EMS, NMS and OSS/BSS 27.3.7 Batching Batching allows a client to send a sequence of call messages to a server. It uses reliable byte stream protocols like TCP for transport. The client never waits for a reply from the server, and the server does not send replies to batch requests. A sequence of batch calls is usually terminated by a RPC to flush the pipeline. Since the server does not respond to every call, the client can generate new calls in parallel, with the server executing previous calls. In addition, the reliable connection oriented implementa- tion can buffer many calls and send them to the server in a single write system call. The RPC architecture is designed SO that a client sends a call to a server and waits for a reply that the call has succeeded. Clients do not compute while serv- ers are processing a call, which is inefficient if the client does not want or need an acknowledgment for every message sent. The RPC batch facilities make it possible for clients to continue computing while waiting for a response. 27.3.8 Authentication Identification is the means to present or assert an identity that is recognizable to the receiver. Authentication provides the actions to verify the truth of the asserted iden- tity. Once the client is identified and verified, access control can be implemented. Access control is the mechanism that provides permission to allow the requests made by the user to be granted, based upon the user's authentic identity. Access control is not provided in RPC and must be supplied by the application. Several different authentication protocols are supported in RPC. A field in the RPC header indicates what protocol is being used. The RPC protocol provides the fields neces- sary for a client to identify itself to a service and vice versa. The call message has two authentication fields, the credentials and verifier. The reply message has one authentication field, the response verifier. The RPC protocol specificat