Which of the following topologies has the highest reliability?

It is a single computer in a network reserved for serving the needs of the network.

In networking, the Open Systems Interconnection is commonly called as OSI model. It has a 7 layer architecture for the communication.

In OSI network architecture, the routing is performed by network layer which is layer number 3 with the help of intermediate routers.

Internet Service Provider (ISP) is a company offering access to internet. They offer various services:

1. Internet Access

2. Domain name registration

3. Dial-up access

4. Leased line access

There exist several ways to connect to the internet. Following are these connection types available:

* Dial-up Connection

* ISDN

* DSL

* Cable TV Internet connections

* Satellite Internet connections

* Wireless Internet Connections

A stub network has only one default path to non-local hosts and no outside network knowledge. Non-local stub network traffic uses a single logical path when traveling in and out of the network.

Stub networks are essentially local area networks (LAN) that either do not connect to the outside and relay data packets internally or are dead-end LANs that know of only one network exit. Stub networks may have multiple connections but use one path to single points of destination.

Hence, a stub network is a network that has only one entry and exit point.

An IP address (internet protocol address) is a numerical representation that uniquely identifies a specific interface on the network. Addresses in IPv4 are 32-bits long. This allows for a maximum of 4,294,967,296 (2^32) unique addresses. Addresses in IPv6 are 128-bits, which allows for 3.4 x 1038 (2^128) unique addresses.

IP addresses available to the internet are classified as Public.

virtual LAN (VLAN) is any broadcast domain that is partitioned and isolated in a computer network at the data link layer (OSI layer 2). LAN is the abbreviation for local area network and in this context, virtual refers to a physical object recreated and altered by additional logic.

VLANs work by applying tags to network packets and handling these tags in networking systems – creating the appearance and functionality of network traffic that is physically on a single network but acts as if it is split between separate networks. In this way, VLANs can keep network applications separate despite being connected to the same physical network, and without requiring multiple sets of cabling and networking devices to be deployed.

The function of PAD (Packet Assembler Disassembler) is described in a document known as X.3. The standard protocol has been defined between the terminal and the PAD, called X.28; another standard protocol exists between hte PAD and the network, called X.29.