The Up to date Guide To 200-105 dumps

Answer: B,D 

Explanation: 

Link State routing protocols, such as OSPF and IS-IS, converge more quickly than their distance vector routing protocols such as RIPv1, RIPv2, EIGRP and so on, through the use of flooding and triggered updates. In link state protocols, changes are flooded immediately and computed in parallel. Triggered updates improve convergence time by requiring routers to send an update message immediately upon learning of a route change. These updates are triggered by some event, such as a new link becoming available oor an existing link failing. The main drawbacks to link state routing protocols are the amount of CPU overhead involved in calculating route changes and memory resources that are required to store neighbor tables, route tables and a complete topology table. http://www.ciscopress.com/articles/article.asp?p=24090&seqNum=4 

Answer: C 

Explanation: 

Spanning Tree from PVST+ to Rapid-PVST Migration Configuration Example Reference 1: http://www.cisco.com/en/US/products/hw/switches/ps708/products_configuration_example 09186a00807b0670.shtml 

Reference 2: http://www.cisco.com/en/US/tech/tk389/tk621/technologies_white_paper09186a0080094cf a.shtml 

PVST+ is based on IEEE802.1D Spanning Tree Protocol (STP). But PVST+ has only 3 port states (discarding, learning and forwarding) while STP has 5 port states (blocking, listening, learning, forwarding and disabled). So discarding is a new port state in PVST+. 

Background Information 

802.1D Spanning Tree Protocol (STP) has a drawback of slow convergence. Cisco 

Catalyst switches support three types of STPs, which are PVST+, rapid-PVST+ and MST. 

PVST+ is based on IEEE802.1D standard and includes Cisco proprietary extensions such 

as BackboneFast, UplinkFast, and PortFast. Rapid-PVST+ is based on IEEE 802.1w 

standard and has a faster convergence than 802.1D. RSTP (IEEE 802.1w) natively 

includes most of the Cisco proprietary enhancements to the 802.1D Spanning Tree, such 

as BackboneFast and UplinkFast. Rapid-PVST+ has these unique features: 

Uses Bridge Protocol Data Unit (BPDU) version 2 which is backward compatible with the 

802.1D STP, which uses BPDU version 0. 

All the switches generate BPDUs and send out on all the ports every 2 seconds, whereas 

in 802.1D STP only the root bridge sends the configuration BPDUs. 

Port Roles—Root port, designated port, alternate port and backup port. 

Port States—Discarding, Learning, and Forwarding. 

Port Types—Edge Port (PortFast), Point-to-Point and Shared port. 

Rapid-PVST uses RSTP to provide faster convergence. When any RSTP port receives 

legacy 802.1D BPDU, it falls back to legacy STP and the inherent fast convergence 

benefits of 802.1w are lost when it interacts with legacy bridges. 

Answer: C 

Explanation: 

DLCI 16 and DLCI 19 need to act like a point-to-point link and will therefore need to be on the same network as will DLCI 17 and DLCI 28. With this information we can see that option "B" is the only option that has the corresponding DLCI's on the same network based on the ip addresses and subnetmask. Option "D" is incorrect because, this would put the same network on both interfaces of the R2 router. Option "A" is similar. 

Answer: B,C 

Explanation: A loopback interface never comes down even if the link is broken so it provides stability for the OSPF process (for example we use that loopback interface as the router-id) - B is correct. 

The router-ID is chosen in the order below: 

The highest IP address assigned to a loopback (logical) interface. If a loopback interface is not defined, the highest IP address of all active router’s physical interfaces will be chosen. 

-The loopback interface will be chosen as the router ID of RouterB - C is correct. 

Answer: B 

Explanation: 

High-Level Data Link Control (HDLC) - HDLC is the default encapsulation type on point-to-point, dedicated links, and circuit-switched connections. It is used typically when communicating between two Cisco devices. It is a bit-oriented synchronous data link layer protocol. Point-to-Point Protocol (PPP) - Provides router-to-router and host-to network connections over synchronous and asynchronous circuits. PPP was designed to work with several network layer protocols, such as IP, and IPX. PPP also has built in security mechanisms such as PAP and CHAP X.25/Link Access Procedure, Balanced (LAPB) - ITU-T standard that defines how connections between DTE and DCE are maintained for remote terminal access and computer communications in public data networks. X.25 specifies LAPB, a data line layer protocol. X.25 is a predecessor to Frame Relay. Frame Relay - Industry standard, switched data link layer protocol that handles multiple virtual circuits. It is a next-generation to X.25 that is streamlined to eliminate some of the time-consuming processes (such as error correction and flow control) that were employed in X.25. 

Answer: A,B,F 

Explanation: 

The question says "no other configuration changes have been made" so we can 

understand these switches have the same bridge priority. SwitchC has lowest MAC 

address so, it will become root bridge and 2 of its ports (Fa0/1 & Fa0/2) will be designated 

ports (DP). Because SwitchC is the root bridge the 2 ports nearest SwitchC on SwitchA 

(Fa0/1) and SwitchD (Gi0/2) will be root ports (RP) -> B and F are correct. 

SwitchB must have a root port so which port will it choose? To answer this question we 

need to know about STP cost and port cost. 

In general, "cost" is calculated based on bandwidth of the link. The higher the bandwidth on 

a link, the lower the value of its cost. Below are the cost values you should memorize: 

Link speed Cost SwitchB will choose the interface with lower cost to the root bridge as the root port so we must calculate the cost on interface Gi0/1 & Gi0/2 of SwitchB to the root bridge. This can be calculated from the "cost to the root bridge" of each switch because a switch always advertises its cost to the root bridge in its BPDU. The receiving switch will add its local port cost value to the cost in the BPDU. SwitchC advertises its cost to the root bridge with a value of 0. Switch D adds 4 (the cost value of 1Gbps link) and advertises this value (4) to SwitchB. SwitchB adds another 4 and learns that it can reach SwitchC via Gi0/1 port with a total cost of 8. The same process happens for SwitchA and SwitchB learns that it can reach SwitchC via Gi0/2 with a total cost of 23 -> Switch B chooses Gi0/1 as its root port. Now our last task is to identify the port roles of the ports between SwitchA & SwitchB. It is rather easy as the MAC address of SwitchA is lower than that of SwitchB so Fa0/2 of SwitchA will be designated port while Gi0/2 of SwitchB will be alternative port. 

Answer: A 

Explanation: Cisco supports two Frame Relay encapsulation types: the Cisco encapsulation and the IETF Frame Relay encapsulation, which is in conformance with RFC 1490 and RFC 2427. The former is often used to connect two Cisco routers while the latter is used to connect a Cisco router to a non-Cisco router. You can test with your Cisco router when typing the command Router(config-if)#encapsulation frame-relay ? on a WAN link. Note: Three LMI options are supported by Cisco routers are ansi, Cisco, and Q933a. They represent the ANSI Annex D, Cisco, and ITU Q933-A (Annex A) LMI types, respectively. HDLC is a WAN protocol same as Frame-Relay and PPP so it is not a Frame Relay encapsulation type. 

Answer: D 

Explanation: 

If a router-id is not configured manually in the OSPF routing process the router will automatically configure a router-id determined from the highest IP address of a logical interface (loopback interface) or the highest IP address of an active interface. If more than one loopback interfaces are configured, the router will compare the IP addresses of each of the interfaces and choose the highest IP address from the loopbacks. 

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: 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.