In this chapter, the fundamentals of communication protocols are presented, and then a special application area, the telecommunications management is introduced. The main part of this chapter deals with the telecommunications management protocols. First, the model for Telecommunication Management Network is explained, and then the most widely used protocol, the Simple Network Management Protocol (SNMP), is introduced. This is followed by a discussion on the open system management protocols and the mobile Internet management protocols for Authentication, Authorization and Accounting (AAA), their comparison and evaluation. Subsequently, the expected trends are presented. The conclusion part summarizes the content of this chapter emphasizing the main ideas.
This section provides an overview of the basics of communication protocols and the telecommunications management. The communication protocols can be compared to dialogues. A simple protocol specifies the rules of a message exchange between the network nodes fulfilling some communication task. The rules are applicable to three areas: the message format, the message exchange and the time assumptions. The message is similar to a word in a human dialogue, where the message format is the correctly spelled word. The message exchange means the phrase or sentences told to each other. The correct message exchange has some goal, e.g. inquiring some information. In a network this could be the task of monitoring a network resource. Monitoring needs a request to read a parameter value and a response with the value of that. The response time is limited. It is similar to a human dialogue, i.e. asking a question and waiting for the answer.
The communication protocols are standardized. This worldwide standardization enables the extension of the network. The network nodes have a layered structure, either the five layer of TCP/IP net, or the seven layer architecture according to the Open System Interconnection (OSI) standards. A protocol specifies the message exchange between peer layers of two different nodes. The telecommunications management protocols are generally application layer protocols. A protocol message has typically two parts, a header part and a data part (see Figure 1). Figure 1 shows the general message structure composed of the header and the data. The header contains the message identifier, the identifier of the source and destination nodes. Sometimes an indication of priority is also included. The presence of other fields in the header depends on the function of the message. Some fields contain values that are constant, others values are variable.
Key Terms in this Chapter
Authentication: Authentication means that a user who is requesting services is a valid user of the network services requested.
Quality of Services (QoS): Quality of Services refers to an ability to deliver network services according to the parameters specified in a service level. Quality of Services is also an agreement containing service availability, delay, throughput and packet loss ratio, and the ability to provide different priority to different applications, users or data flows.
Provisioned Policy: Provisioned policy is a model where network elements are pre-configured, based on policy, prior to processing event. Provisional policy is contrasted with outsourced policy.
Outsourced Policy: Outsourced policy is a model where a policy enforcement device issues queries to delegate a decision for a specific policy event to another component external to it.
Accounting: Accounting means the tracking of network resources by users. The typical information gathered in the accounting process is the identity of the user, the level of the services delivered, and the time interval in which the services were being used.
Policy: Policy is the ability to define conditions for accepting, rejecting and notifying routes according to the actual information.
Authorization: Authorization means that a user can access some services based on its authentication, but the access in only provided for a given amount of time. Therefore authorization is a kind of limitation of the authentication rights.