A bit of a battle is shaping up inside the industry over 2G, 2.5G, and 2.75G solutions. Verizon and Sprint are backing (code division multiple access) CDMA2000 technology. AT&T Wireless, Cingular Wireless, and VoiceStream are backing the Global System of Mobility/General Packet Radio Service (GSM/GPRS) systems, which provide speeds that range from 15 to 40 kbps. Nextel is backing its iDEN (Motorola proprietary version of TDMA with its unique push-to-talk radio capability)..
IP ARP is widely understood and relatively simple. As a result, it is hard to ask difficult questions about ARP on an exam. However, the topics of Frame Relay Inverse ARP (InARP), its use, defaults, and when static mapping must be used lend themselves to being the source of tricky exam questions. So, this section covers Frame Relay InARP to show some of the nuances of when and how it is used. InARP discovers the DLCI to use to reach a particular adjacent IP address. However, ..
Integrated Services Digital Network (ISDN) is used by telephone companies to carry digitized voice and data over the existing telephone system. ISDN has emerged as one of the leading technologies for telecommuting and remote office connection into the corporate headquarters. On the seven layer model, ISDN operates at the physical, data link, and network layers. ISDN basic rate interface (BRI) provides two barrier channels (commonly referred as B channels). Each of these B ch..
Each router in an HSRP group has its own unique IP address assigned to an interface. This address is used for all routing protocol and management traffic initiated by or destined to the router. In addition, each router has a common gateway IP address, the virtual router address, which is kept alive by HSRP. This address also is referred to as the HSRP address or the standby address. Clients can point to that virtual router address as their default gateway, knowing that a rout..
If an interface is in Layer 3 mode and you need to reconfigure it for Layer 2 functionality instead, use the following command sequence: Switch(config)# interface type mod/num Switch(config-if)# switchport The switchport command puts the port in Layer 2 mode. Then you can use other switchport command keywords to configure trunking, access VLANs, and so on. As displayed in Figure 11-2, several Layer 2 ports exist, each assigned to a specific VLAN. A Layer 2 port also can act..
