31 Days Before Your CCNA Exam

Day 4 319Broadband WirelessUntil recently, the main limitation of wireless access has been the need to be within range of awireless router or a wireless modem that has a wired connection to the Internet. The following newdevelopments in broadband wireless technology are changing this situation:■Municipal Wi-Fi: Many cities have begun setting up municipal wireless networks. Some ofthese networks provide high-speed Internet access for free or for substantially less than theprice of other broadband services.■ WiMAX: Worldwide Interoperability for Microwave Access (WiMAX) is a new IEEE 802.16technology that is just beginning to come into use. It provides high-speed broadband servicewith wireless access and provides broad coverage like a cell phone network rather than throughsmall Wi-Fi hotspots.■Satellite Internet: Typically used by rural users where cable and DSL are unavailable.Metro EthernetMetro Ethernet uses IP-aware Ethernet switches in the service provider’s network cloud to offerenterprises converged voice, data, and video services at Ethernet speeds. Some benefits of MetroEthernet include the following:■■■Reduced expenses and administration: Enables businesses to inexpensively connect numeroussites in a metropolitan area to each other and to the Internet without the need for expensiveconversions to ATM or Frame Relay.Easy integration with existing networks: Connects easily to existing Ethernet LANs.Enhanced business productivity: Metro Ethernet enables businesses to take advantage ofproductivity-enhancing IP applications that are difficult to implement on TDM or Frame Relaynetworks, such as hosted IP communications, VoIP, and streaming and broadcast video.Choosing a WAN Link OptionTable 4-2 compares the advantages and disadvantages of the various WAN connection options reviewed.Table 4-2Choosing a WAN Link ConnectionOption Description Advantages Disadvantages SampleProtocolsLeased line Point-to-point connection Most secure Expensive PPP, HDLC,between two computers’ LANs.SDLCCircuit A dedicated circuit path is Less expensive Call setup PPP, ISDNswitching created between endpoints.Best example is dialupconnections.Packet Devices transport packets via a Highly efficient use Shared media X.25, Frameswitching shared single point-to-point of bandwidth across link Relayor point-to-multipoint linkacross a carrier inter network.Variable-length packets aretransmitted over PVCs or SVCs.continues