Answer: E 

Explanation: 

The command frame-relay map ip 10.121.16.8 102 broadcast means to map the remote IP 

10.121.16.8 to the local DLCI 102. When the “broadcast” keyword is included, it turns Frame Relay network as a broadcast network, which can forward broadcasts. 

Answer: B 

Explanation: 

What Is Administrative Distance? 

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: 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: 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,C 

Explanation: 

OSPF uses a LSDB (link state database) and fills this with LSAs (link state advertisement). The link types are as follows: 

LSA Type 1:. Router LSA  

LSA Type 2:.. . . . . . . .  Network LSA  

LSA Type 3:. Summary LSA  

LSA Type 4:. Summary ASBR LSA  

LSA Type 5:. Autonomous system external LSA  

LSA Type 6:. Multicast OSPF LSA  

LSA Type 7:. Not-so-stubby area LSA  

LSA Type 8:. External attribute LSA for BGP  

If all routers are in the same area, then many of these LSA types (Summary ASBR LSA, external LSA, etc) will not be used and will not be generated by any router. 

All areas in an Open Shortest Path First (OSPF) autonomous system must be physically connected to the backbone area (Area 0). In some cases, where this is not possible, you can use a virtual link to connect to the backbone through a non-backbone area. You can also use virtual links to connect two parts of a partitioned backbone through a non-backbone area. The area through which you configure the virtual link, known as a transit area, must have full routing information. The transit area cannot be a stub area. Virtual links are not ideal and should really only be used for temporary network solutions or migrations. However, if all locations are in a single OSPF area this is not needed. 

Answer: B 

Explanation: 

You do not have to assign a separate subnet per sub-interface .if you're using a Class A network (10.x.x.x/8), you blow the whole network on a few connections (if you used VLSM, you could use a better mask, limit the addresses used). if you used 10.0.0.0/8, you would not be assigning the entire /8 to a single network. You would select a subnet mask for the network and then, you would have to use that mask with all subnets of the network. So if you chose a /24 mask, that would mean that you would have to use a /24 mask for even point-to-point links. 

Answer: A 

Explanation: 

From the CCNA ICND2 Exam book: “Routers decrement the TTL by 1 every time they forward a packet; if a router decrements the TTL to 0, it throws away the packet. This prevents packets from rotating forever.” I want to make it clear that before the router forwards a packet, the TTL is still remain the same. For example in the topology above, pings to S0/1 and S0/0 of Router 2 have the same TTL. 

The picture below shows TTL values for each interface of each router and for Host B. 

Notice that Host A initializes ICMP packet with a TTL of 255: 

Answer:  

Explanation: 

Enhanced Interior Gateway Routing Protocol (EIGRP) is a Cisco proprietary routing protocol, so it is vendor-specific. By default, EIGRP internal routes have an administrative distance value of 90. OSPF uses cost as its metric. By default, the cost of an interface is calculated based on bandwidth with the formula cost= 10000 0000/bandwidth (in bps). OSPF elects a DR on each broadcast and nonbroadcast multiaccess networks (like Ethernet and Frame Relay environments, respectively). It doesn’t elect a DR on point-to-point link (like a serial WAN). 

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 

Answer: E 

Explanation: 

What Is Administrative Distance? http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094195.shtml 

Select the Best Path Administrative distance is the first criterion that a router uses to determine which routing protocol to use if two protocols provide route information for the same destination. Administrative distance is a measure of the trustworthiness of the source of the routing information. Administrative distance has only local significance, and is not advertised in routing updates. Note: The smaller the administrative distance value, the more reliable the protocol. For example, if a router receives a route to a certain network from both Open Shortest Path First (OSPF) (default administrative distance - 110) and Interior Gateway Routing Protocol (IGRP) (default administrative distance - 100), the router chooses IGRP because IGRP is more reliable. This means the router adds the IGRP version of the route to the routing table.