Cisco 200-105 Free Practice Questions

Answer: D 

Explanation: 

http://www.cisco.com/en/US/docs/ios/iproute_ospf/command/reference/iro_osp3.html#wp1 01217 Examples The following is sample output from the show ip ospf database command when no arguments or keywords are used: Router# show ip ospf database OSPF Router with id(192.168.239.66) (Process ID 300) 

Answer: A 

Explanation: 

Open Shortest Path First http://en.wikipedia.org/wiki/Open_Shortest_Path_First 

The configuration of R1 shows "router ospf 1" however, the diagram also shows that both routers should be in the backbone OSPF Area of "0". When routers are in different OSPF areas they will not form a neighbor relationship. Neighbor relationships As a link state routing protocol, OSPF establishes and maintains neighbor relationships in order to exchange routing updates with other routers. The neighbor relationship table is called an adjacency database in OSPF. Provided that OSPF is configured correctly, OSPF forms neighbor relationships only with the routers directly connected to it. In order to form a neighbor relationship between two routers, the interfaces used to form the relationship must be in the same area. Generally an interface is only configured in a single area, however you can configure an interface to belong to multiple areas. In the second area, such an interface must be configured as a secondary interface. (A neighbor state simulation shows how neighbor state changes from Down to Full Adjacency progressively with exchanging Hello, DD, Request, Update, and Ack packets). 

Answer: A,C 

Explanation: 

On each WAN connection, data is encapsulated into frames before itcrosses the WAN link. The following are typical WAN protocols:1. High-level Data Link Control (HDLC): The Cisco default encapsulation type onpoint-to-point connections, dedicated links, and circuit-switches connections.2. PPP: Provides router-to-router and host-to-network connections over synchronous andasynchronous circuits. PPP was designed to work with several network layer protocols,including IP.3. Frame-relay: A successor to X.25. This protocol is an industry-standard, switchesdata-link layer protocol that handles multiple virtual circuits 

http://en.wikipedia.org/wiki/Wide_area_network 

Answer: E 

Explanation: 

The term dynamic indicates that the DLCI number and the remote router IP address 

172.16.3.1 are learned via the Inverse ARP process. 

Inverse ARP is a technique by which dynamic mappings are constructed in a network, allowing a device such as a router to locate the logical network address and associate it with a permanent virtual circuit (PVC). 

Answer: B 

Explanation: 

Interface fa0/0 breaks into sub-interfaces and Main_Campus router is connected with switch via fa0/0 .Subinterfaces configured with different subnet masks so the same switch has multiple vlans and allows communication between these VLAN's. For routing and inter-vlan we need to configure a trunk port. So B will be the correct answer. 

Answer: C 

Explanation: 

CCNA Tutorial: The OSPF Router ID (RID) http://www.thebryantadvantage.com/CCNACertificationExamTutorialOSPFRouterIDRID.ht m 

When determining the Router ID (RID) of an OSPF-enabled router, OSPF will always use the numerically highest IP address on the router’s loopback interfaces, regardless of whether that loopback is OSPF-enabled. 

What if there is no loopback? OSPF will then use the numerically highest IP address of the physical interfaces, regardless of whether that interface is OSPF-enabled. 

Answer: C 

Explanation: 

First, the question asks what switch services the printers, so it can be Switch 3 or Switch 4 

which is connected directly to the Printers. 

Designated port is a port that is in the forwarding state. All ports of the root bridge are 

designated ports. 

Switch 3 and Switch 4 has same priority so it will see on lowest MAC address and here 

switch 3 has lowest MAC address. So switch 3 segment will play a Designated port role. 

By comparing the MAC address of Switch 3 and Switch 4 we found that the MAC of Switch 

3 is smaller. Therefore the interface connected to the Printers of Switch 3 will become 

designated interface and the interface of Switch 4 will be blocked. 

Answer: Explanation: 

poison reverse: A router learns from its neighbor that a route is down and the router sends an update back to the neighbor with an infinite metric to that routeLSA: The packets flooded when a topology change occurs, causing network routers to update their topological databases and recalculate routes split horizon: This prevents sending information about a routeback out the same interface that originally learned about the route holddown timer: For a given period, this causes the router to ignore any updates with poorer metrics to a lost network 

The internetwork infrastructure of company XYZ consists of a single OSPF area as shown in the graphic. There is concern that a lack of router resources is impeding internetwork performance. As part of examining the router resources, the OSPF DRs need to be known. All the router OSPF priorities are at the default and the router IDs are shown with each router. 

Which routers are likely to have been elected as DR? (Choose two.) 

A. Corp-1 

B. Corp-2 

C. Corp-3 

D. Corp-4 

E. Branch-1 

F. Branch-2 

Answer: D 

Explanation: 

Committed information rate (CIR): The minimum guaranteed data transfer rate agreed to by the Frame Relay switch. Frames that are sent in excess of the CIR are marked as discard eligible (DE) which means they can be dropped if the congestion occurs within the Frame Relay network. Note: In the Frame Relay frame format, there is a bit called Discard eligible (DE) bit that is used to identify frames that are first to be dropped when the CIR is exceeded. 

Answer: A,C,F 

Explanation: 

Open Shortest Path First Reference: 

http://docwiki.cisco.com/wiki/Open_Shortest_Path_First 

Explanation: 

Additional OSPF features include equal-cost, multipath routing, and routing based on upper-layer type-of-service (TOS) requests. TOS-based routing supports those upper-layer protocols that can specify particular types of service. An application, for example, might specify that certain data is urgent. If OSPF has high-priority links at its disposal, these can be used to transport the urgent datagram. 

OSPF supports one or more metrics. If only one metric is used, it is considered to be arbitrary, and TOS is not supported. If more than one metric is used, TOS is optionally supported through the use of a separate metric (and, therefore, a separate routing table) for each of the eight combinations created by the three IP TOS bits (the delay, throughput, and reliability bits). For example, if the IP TOS bits specify low delay, low throughput, and high reliability, OSPF calculates routes to all destinations based on this TOS designation. IP subnet masks are included with each advertised destination, enabling variable-length subnet masks. With variable-length subnet masks, an IP network can be broken into many subnets of various sizes. This provides network administrators with extra network-configuration flexibility. 

Answer: A 

Reference: 

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094195.shtml 

Administrative distance is the feature that routers use in order to select the best path. 

Administrative distance defines the reliability of a routing protocol. Each routing protocol is prioritized in order of most to least reliable (believable) with the help of an administrative distance value. Lowest Administrative distance will be chosen first. 

Answer: B,E 

Explanation: 

http://www.cisco.com/en/US/tech/tk389/tk621/technologies_white_paper09186a0080094cf a.shtml 

Port Roles The role is now a variable assigned to a given port. The root port and designated port roles remain, while the blocking port role is split into the backup and alternate port roles. The Spanning Tree Algorithm (STA) determines the role of a port based on Bridge Protocol Data Units (BPDUs). In order to simplify matters, the thing to remember about a BPDU is there is always a method to compare any two of them and decide whether one is more useful than the other. This is based on the value stored in the BPDU and occasionally on the port on which they are received. This considered, the information in this section explains practical approaches to port roles. 

Compatibility with 802.1D RSTP is able to interoperate with legacy STP protocols. However, it is important to note that the inherent fast convergence benefits of 802.1w are lost when it interacts with legacy bridges. 

Answer: B 

Explanation: 

OSPF states for adjacency formation are (in order) Down, Init, Attempt, 2-way, Exstart, 

Exchange, Loading and Full. 

Reference: 

Why Are OSPF Neighbors Stuck in Exstart/Exchange State? 

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080093f0d.shtml 

Answer: A 

Explanation: 

Router_E learns two subnets subnets 208.149.23.64 and 208.149.23.96 via Router_A through FastEthernet interface. The interface cost is calculated with the formula 108 / 

Bandwidth. For FastEthernet it is 108 / 100 Mbps = 108 / 100,000,000 = 1. Therefore the cost is 12 (learned from Router_A) + 1 = 13 for both subnets - B is not correct. 

The cost through T1 link is much higher than through T3 link (T1 cost = 108 / 1.544 Mbps = 

64; T3 cost = 108 / 45 Mbps = 2) so surely OSPF will choose the path through T3 link -> 

Router_E will choose the path from Router_A through FastEthernet0/0, not Serial1/0 - C & 

D are not correct. 

In fact, we can quickly eliminate answers B, C and D because they contain at least one subnet learned from Serial1/0 - they are surely incorrect. 

Answer: B 

Explanation: 

In order to be sufficiently versatile to be portable to a wide variety of environments, PPP provides a Link Control Protocol (LCP). The LCP is used to automatically agree upon the encapsulation format options, handle varying limits on sizes of packets, detect a looped-back link and other common misconfiguration errors, and terminate the link. Other optional facilities provided are authentication of the identity of its peer on the link, and determination when a link is functioning properly and when it is failing. 

Reference: Link Control Protocol 

http://www.ietf.org/rfc/rfc1661.txt 

Answer: D 

Explanation: 

Two terms that appear often in the EIGRP world are "successor" and "feasible successor". A successor is the route with the best metric to reach a destination. That route is stored in the routing table. A feasible successor is a backup path to reach that same destination that can be used immediately if the successor route fails. These backup routes are stored in the topology table. 

Reference: http://study-ccna.com/eigrp-overview