CCENT (Cisco Certified Entry Network Technician) Certification Exam Notes

vi. Others

1. HTTP is the protocol used for accessing the World Wide Web services. HTTP operates over TCP/IP. TCP/IP is the protocol, which is used by all internet applications such as WWW, FTP, Telnet etc. IPX/SPX is proprietary protocol stack of Novell NetWare.

2. If a properly configured workstation is unable to access the network information, it is likely that the DHCP information available with the client workstation had become obsolete. Issuing ipconfig command with /release and /renew commands will enable the client workstation to obtain latest changes to the DHCP server.

3. 127.0.0.1 is the local loopback address defined by the Internet Protocol and used for by a host to ping itself to verify the IP connectivity.

4. Important Layer 2 LAN protocols types:
· 802.3 - Layer 2 protocol that defines Ethernet CSMA/CD protocol
· 802.5 - Layer 2 protocol that defines Token Ring protocol
Note that 802.3, and 802.5 are examples of layer 2 LAN protocols, whereas, HDLC, PPP are examples of layer 2 WAN protocols.

5. A switch forms a single broadcast domain, whereas, it provides an independent collision domain for each port. Here, three ports of the switch are used, and hence it will have three collision domains. On the other hand, a Hub forms a single collision as well as a single broadcast domain. Therefore, the total number of broadcast domains in this case is two, and the total number of collision domains is four.

6. An administrative distance of 0 represents highest trustworthiness of the route.
An administrative distance of 255 represents the lowest trustworthiness of the route.

7. Anytime that you hook up two end-devices like routers, PCs, print
servers, etc. to one another, you'll need a crossover cable. A switch or hub already all have their ports crossed over, so hooking up an end-device to a switch uses a straight-through cable. When hooking up two switch ports together, you use a cross-over cable again.

8. BooTP (Bootstrap Protocol): When a diskless workstation is powered on, it broadcasts a BootP request on the network. A BooTP server responds with its IP address, Default gateway, etc.

9. Debugging output takes priority over other network traffic. Also, the debug all command generates more output than any other debug command, and it can severely affect the router's performance. In practically all cases, it is best to use more specific debug commands.
Extended Service Set (ESS) is a set of two or more Basic Service Sets (BSSes) working together to form a single wireless network. Stations are able to move between BSS within a single ESS yet remain “connected” to the fixed network and so continue to receive emails etc. As a Station moves into a new BSS, it will carry out a re-association procedure with the new AP (Access Point).

10. For accessing a switch over IP network, you need to do some minimum configuration tasks using Console port on the switch. In the given question, the default gateway needs to be configured on the switch for accessing the management interface (VLAN1) from HostA.

11. For communicating between two hosts directly, you need a cross cable. Also, the subnet mask 255.255.255.192 cannot accommodate the given IP addresses. Therefore, you need to change either the host IP addresses so that they are within a given subnet, or change the subnet address itself so that both the hosts are within the subnet.

12. For using full duplex Ethernet transmission, a switch is required. A Hub cannot support full duplex transmission. In full duplex mode, there will not be any frame collisions.

13. Frame tagging is a technique, where a unique identifier is tagged to each frame as it is forwarded through the switch fabric.

14. IANA (Internet Assigned Numbers Authority) is the organization under the Internet Architecture Board (IAB) of the Internet Society that oversees the allocation of Internet Protocol addresses to Internet service providers (ISPs). ICANN (a non governmental organization) has now assumed responsibility for the tasks formerly performed by IANA. ISPs in turn allot IP addresses to small companies, and businesses.

15. In "ad-hoc" or Independent Basic Service Set (IBSS) configuration there is no backbone infrastructure. An IBSS is one BSS or Basic Service Set. Mobiles can talk to each other without the use of an Access Point (AP). In the Extended Service Set (ESS) configuration, there will be two or more Access Points (APs), and users can freely roam between the Access Points without any disconnection or reconfiguration. BSS will use only one Access Point.

16. In Carrier Sense Multiple Access with Collision Detection (CSMA/CD), a node transmits only after listening to the media, and ensuring that no transmission is taking place. Further, sending nodes detect when a collision occurs and stop transmitting immediately, backing off for a random amount of time before trying again. This results in efficient use of the media since the bandwidth of transmitting the entire frame is not wasted.

17. In Cisco routers, the interfaces are “administratively down” by default. You need to enable an interface to use it.

18. Internet connectivity is normally achieved using a WAN connection. Therefore, you need a serial port for connecting to the Internet. On the other hand, a switch normally requires an Ethernet port for connectivity.

19. IP is the protocol that works at Internet layer. It forwards the packets based on the network address (IP address) in the packets and the routing tables.
IP Packets are transported from source network to the destination network by what is known as routing. Hop-by-hop routing model is used by the Internet for delivery of packets. At each hop, the destination IP address is examined, the best next hop is determined by the routing protocol (such as RIP, OSPF or BGP) and the packet is forwarded by one more hop through this route. The same process takes place at the next hop. During this process, the logical addresses remain same. In an IP network, the logical addresses are IP addresses. The hardware interface addresses, such as MAC address change with each hop.

20. IP RIP based networks send the complete routing table during update. The default update interval is 30 seconds.

ISL, 802.1Q are the VLAN trunking protocols associated with Fast Ethernet. The VLAN trunking protocol defined by 802.10 is associated with FDDI. LANE (LAN Emulation) is associated with ATM.

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