Basic Service Set (BSS) provides the basic building-block of an 802.11 wireless LAN. In infrastructure mode, a single access point (AP) together with all associated stations (STAs) is called a BSS; not to be confused with the coverage of an access point, known as the basic service area (BSA 04 LOCAL AREA NETWORK SERVICES OF WIRELESS LAN (i)Basic Service Set (BSS) Figure 4- 11 Basic Service Set
04 LOCAL AREA NETWORK SERVICES OF WIRELESS LAN An extended service set (ESS) is one or more interconnected basic service sets (bss) and their associated lans. Each BSS consists of a single access point (AP) together with all wireless client devices (stations, also called stas) creating a local or enterprise 802.11 wireless LAN (WLAN) (ii) EXTENDED SERVICE SET Figure 4-12 Extended Service Set
04 LOCAL AREA NETWORK CONFIGURATION OF WIRELESS LAN
04 LOCAL AREA NETWORK CONFIGURATION OF WIRELESS LAN
04 LOCAL AREA NETWORK CONFIGURATION OF WIRELESS LAN Figure 4-12 Connection in Wireless LAN
05 PUBLIC DATA NETWORK 05
PUBLIC DATA NETWORK 05 CONTENTS 5.1 Understand Public Data Network 5.2 Apply the knowledge of common switching network 5.3 Apply the knowledge of packet switching 5.4 Understand Virtual Private Network (VPN) 5.5 Remember Metropolitan-area Ethernet (Metro-E) 5.6 Apply the knowledge of Multiprotocol Label Switching (MPLS)
Networks are used to interconnect many devices. We have checked with Local Area Networks Now, wide area networks Since the invention of the telephone, circuit switching has been the dominant technology for voice communications. Since 1970, packet switching has evolved substantially for digital data communications. It was designed to provide a more efficient facility than circuit switching for bursty data traffic. Two types of packet switching: Datagram (such as today’s Internet) Virtual circuit (such as Frame Relay, ATM) Notes 05 PUBLIC DATA NETWORK Understand Public Data Network 5.1 Figure 5-1 Component in Public Data Network
05 PUBLIC DATA NETWORK Data Network A data network is a system that transfers data between network access points (nodes) through data switching, system control and interconnection transmission lines Figure 5-2 Example of Data Network
Value Added Network (VANs) VAN refers to a private network provider that leases communication lines to its subscribers. It is primarily for routing, storing and delivering electronic data interchange (EDI) messages. A value-added network (VAN) also provides other services such as message encryption, retransmission and support. 05 PUBLIC DATA NETWORK Value Added Network
05 PUBLIC DATA NETWORK SWITCHING NETWORK TYPES OF COMMON SWITCHING NETWORK Figure 5-3 Types of switching network
05 PUBLIC DATA NETWORK CIRCUIT SWITCHING Figure 5-4 Circuit switching
In message switching, the source and destination nodes are not directly connected. Instead, the intermediary nodes (mainly switches) are responsible for transferring the message from one node to the next. Thus, every intermediary node inside the network needs to store every message prior to retransferring the messages one-by-one as adequate resources become available. 05 PUBLIC DATA NETWORK MESSAGE SWITCHING
In Message Switching, each switch stores the whole messages and forwards it to the next switch. No end-to-end resources are allocated. This method is also known as store-and-forward 05 PUBLIC DATA NETWORK MESSAGE SWITCHING Figure 5-5 Operation in Mesage Switching
Refers to protocols in which messages are divided into packets before they are sent. Packets are reassembled into the original message at the destination computer. 05 PACKET SWITCHING PUBLIC DATA NETWORK
05 PUBLIC DATA NETWORK There are two types of packet switching : 1.Virtual Circuit Packet Switching 2.Datagram Packet Switching VC Packet Switching is an approach in which a logical path or virtual circuit connection is done between sender and receiver. Figure 5-6 _1 Virtual Circuit Switching
05 PUBLIC DATA NETWORK Figure 5-6_2 Virtual Circuit Switching Virtual Circuit network protocols establish a logical route called virtual circuit packets use the same route; data arrive in order similar to circuit switching but the route is not dedicated need call setup Figure 5-6_3 Virtual Circuit Switching
A virtual private network (VPN) is programming that creates a safe, encrypted connection. Typically, it is used over a less secure network, such as the public internet. It uses tunneling protocols to encrypt data at the sending end, and decrypt it at the receiving end. The originating and receiving network addresses are also encrypted to provide better security for online activities 05 PUBLIC DATA NETWORK VIRTUAL PRIVATE NETWORK (VPN) Figure 5- 7 Virtual Circuit Switching Must lease an Internet connection from any Internet service provider (ISP). It might use a DSL or cable modem. Then it connects a VPN gateway (a specially designed router) to each Internet access circuit to provide access from user's networks to the VPN. The VPN gateways enable user to create PVCs through the Internet that are called tunnels
INTERNET PROTOCOL VIRTUAL PRIVATE NETWORK (IPVPN) 05 PUBLIC DATA NETWORK An acronym for Internet Protocol Virtual Private Network, IPVPN is separated from the public internet, travelling via a private connection to each remote site. Figure 5-8 Internet Protocol Virtual private network Internet Protocol Virtual Private Network (IP-VPN) is one of the many types of WAN technology available. You may have used a Virtual Private Network (VPN), a solution that lets users access a network remotely via a public internet connection
A virtual private network (VPN) is programming that creates a safe, encrypted connection. Typically, it is used over a less secure network, such as the public internet. It uses tunneling protocols to encrypt data at the sending end, and decrypt it at the receiving end. The originating and receiving network addresses are also encrypted to provide better security for online activities 05 PUBLIC DATA NETWORK Metropolitan-area Ethernet (Metro-E)
05 PUBLIC DATA NETWORK Main components of Metro-E a. Access User b. Aggregation or Distribution c. Edge Network d. Provider node Figure 5-9 Component of Metro -E
• Multiprotocol Label Switching (MPLS) is a type of data-carrying technique for high-performance telecommunications networks. • MPLS directs data from one network node to the next based on short path labels rather than long network addresses, avoiding complex lookups in a routing table. • The labels identify virtual links (paths) between distant nodes rather than endpoints. • MPLS can encapsulate packets of various network protocols, hence its name "multiprotocol". Multiprotocol Label Switching -MPLS 05 PUBLIC DATA NETWORK Figure 5-10 Multiprotocol Label Switching MPLS
05 PUBLIC DATA NETWORK Question 2 List the FOUR component in Metro E? Question 1 Draw TWO(2) types of common switching network. Question 3 Show the transmission in Datagram Questions
References Main reference supporting the course Jerry FitzGerald, Alan Dennis, Alexandra Durcikova (2014). Business Data Communications and Networking. 12th Edition Wiley. Additional references supporting the course Forouzan, B.A. (2012). Data Communications and Networking. 5th Edition. Mc Graw Hill. Jeffrey S. Beasley, Gary M. Miller (2013). Modern Electronic Communication. 10th Edition Pearson/Prentice Hall. William Stallings (2015). Data And Computer Communications, International Edition. 10th Edition. Pearson Education Limited. William Stallings, Thomas L. Case (2013). Business Data Communications: International Edition. 7th Edition. Pearson Education Limited. Wayne T. (2004). Electronic Communication Systems: Fundamentals Through Advance. 6th Edition. Prentice Hall.
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