1.8 Network Management Architecture

For an operational network, to have a network management architecture the various functions can be divided into "planes." there are three different planes specifically. The management plane addresses router configuration and collection of various statistics, such as packet throughput, on a link. Router configuration refers to configuration of a router in a network by assigning an IP address, identifying links to its adjacent routers, invoking one or more routing protocols for operational usage, and so on.

The control plane exchanges control information between routers for management of a variety of functions, such as setting up a virtual link. The control plane is also involved in identifying the path to be taken between the endpoints of this virtual link, which relies on the routing information exchange. The routing-related functions are in the control plane, and the data transfers, such as the web or email, are in the data plane. These two planes, as well as the management plane, use IP for communication, so at the IP layer; there is no distinction between these functional planes. In certain networking environments, some functions can overlap across different planes. Thus, the three planes can be thought of as interdependent.

The IP layer provides a common interface between different transport-layer protocols and different link-layer devices. The network layer for this project will be modeled after IPv4. The Internetwork Protocol (IP) [RFC791] provides a best effort network layer service for connecting computers to form a computer network. Each computer is identified by one or more globally unique IP addresses.

1.8 Network Management Architecture

The network layer PDUs are known as either "packets" or "datagrams". Each packet carries the IP address of the sending computer and also the address of the intended recipient or recipients of the packet. Other management information is also carried.

The IP network service transmits datagrams between intermediate nodes using IP routers. The routers themselves are simple, since no information is stored concerning the datagrams which are forwarded on a link. The most complex part of an IP router is concerned with determining the optimum link to use to reach each destination in a network. This process is known as "routing". Although this process is computationally intensive, it is only performed at periodic intervals.

An IP network normally uses a dynamic routing protocol to find alternate routes whenever a link becomes unavailable. This provides considerable robustness from the failure of either links or routers, but does not guarantee reliable delivery. Some applications are happy with this basic service and use a simple transport protocol known as the User Datagram Protocol (UDP) to access this best effort service.

Most Internet users need additional functions such as end-to-end error and sequence control to give a reliable service (equivalent to that provided by virtual circuits). This reliability is provided by the Transmission Control Protocol (TCP) which is used end-to-end across the Internet.

1.8 Network Management Architecture

In a LAN environment, the protocol is normally carried by Ethernet, but for long distance links, other link protocols using fibre optic links are usually used. Other protocols associated with the IP network layer are the Internet Control Message Protocol (ICMP) and the Address Resolution Protocol (arp). The implementation does not need to handle IP fragmentation, multicast, IP header options, and Type-of-Service (ToS). Therefore, your fragment offset field should always be zero. The identification field is used to uniquely identify each IP packet sent by a host. It is typically used for fragmentation and reassembly.