400-101 Exam - CCIE Routing and Switching (v5.0)

certleader.com

Q1. Which statement is true about Fast Link Pulses in Ethernet? 

A. They are used during collision detection. 

B. They are used only if the media type is optical. 

C. They are part of UniDirectional Link Detection. 

D. They are used during autonegotiation. 

Answer:

Explanation: 

To make sure that your connection is operating properly, IEEE 802.3 Ethernet employs normal link pulses (NLPs), which are used for verifying link integrity in a 10BaseT system. This signaling gives you the link indication when you attach to the hub and is performed between two directly connected link interfaces (hub-to-station or station-to-station). NLPs are helpful in determining that a link has been established between devices, but they are not a good indicator that your cabling is free of problems. An extension of NLPs is fast link pulses. These do not perform link tests, but instead are employed in the autonegotiation process to advertise a device's capabilities. 

Reference: 

http://www.cisco.com/en/US/docs/internetworking/troubleshooting/guide/tr1904.html 

Q2. Which statement about the BGP originator ID is true? 

A. The route reflector always sets the originator ID to its own router ID. 

B. The route reflector sets the originator ID to the router ID of the route reflector client that injects the route into the AS. 

C. The route reflector client that injects the route into the AS sets the originator ID to its own router ID. 

D. The originator ID is set to match the cluster ID. 

Answer:

Explanation: 

An RR reflecting the route received from a RR-Client adds: 

. Originator ID- a 4-byte BGP attribute that is created by the RR. This attribute carries the Router ID of the originator of the route in the local AS. If the update comes back to the originator, it ignores the update. 

. Cluster List- A Cluster List is a list of Cluster IDs that an update has traversed. When a route reflector sends a route received from a client to a non-client, it appends the local Cluster ID. If a route reflector receives a route whose Cluster List contains the local Cluster ID, it ignores the update. 

Reference: https://sites.google.com/site/amitsciscozone/home/bgp/bgp-route-reflectors 

Q3. DRAG DROP 

Drag and drop the router preference on the left to the correct routing sequence (from most preferred to least preferred) on the right. 

Answer:  

Q4. Refer to the exhibit. 

All routers are running EIGRP and the network has converged. R3 and R4 are configured as EIGRP Stub. If the link between R1 and R3 goes down, which statement is true? 

A. R1 sends traffic destined to 192.168.0.100 via R2. 

B. R2 does not have a route to 192.168.0.0/24 in the routing table. 

C. The prefix 192.168.0.0/24 becomes stuck-in-active on R4. 

D. R3 does not advertise 192.168.0.0/24 to R4 anymore. 

Answer:

Q5. Refer to the exhibit. 

Which action must you take to enable full reachability from router C to router D? 

A. Build an OSPF virtual link. 

B. Build an OSPF sham link. 

C. Configure mutual redistribution between OSPF and EIGRP on routers A and B. 

D. Add a static route on router D. 

Answer:

Explanation: 

For full connectivity, we need to configure mutual redistribution to advertise the EIGRP routes into OSPF and to advertise the OSPF routes into the EIGRP network. This needs to be done at the two border routers that connect to both the EIGRP and OSPF domains. 

Q6. Which statement describes what it means if a router has an OSPF priority set to 0? 

A. A router with the OSPF priority set to 0 is one that can participate in the election of a DR. It has the highest priority. 

B. A router with the OSPF priority set to 0 is one that cannot participate in the election of a DR, but it can become a BDR 

C. A router with the OSPF priority set to 0 is one that cannot participate in the election of a DR. It can become neither a DR nor a BDR. 

D. A router with the OSPF priority set to 0 is one that cannot participate in the election of a BDR, but it can become a DR 

Answer:

Q7. Refer to the exhibit. 

Which command is configured on this router? 

A. bgp update-delay 60 

B. neighbor 10.100.1.1 maximum-prefix 200 

C. neighbor 10.100.1.1 maximum-path 2 

D. neighbor 10.100.1.1 ebgp-multihop 2 

Answer:

Explanation: 

The BGP Maximum-Prefix feature allows you to control how many prefixes can be received from a neighbor. By default, this feature allows a router to bring down a peer when the number of received prefixes from that peer exceeds the configured Maximum-Prefix limit. This feature is commonly used for external BGP peers, but can be applied to internal BGP peers also. When the maximum number of prefixes has been received, the BGP sessions closes into the IDLE state. 

Reference: http://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/25160-bgp-maximum-prefix.html 

Q8. Refer to the exhibit. 

Router A and router B are physically connected over an Ethernet interface, and IS-IS is configured as shown. Which option explains why the IS-IS neighborship is not getting formed between router A and router B? 

A. same area ID 

B. same N selector 

C. same domain ID 

D. same system ID 

Answer:

Explanation: 

With IS-IS, the LSP identifier is derived from the system ID (along with the pseudonode ID and LSP number). Each IS is usually configured with one NET and in one area; each system ID within an area must be unique. The big difference between NSAP style addressing and IP style addressing is that, in general, there will be a single NSAP address for the entire router, whereas with IP there will be one IP address per interface. All ISs and ESs in a routing domain must have system IDs of the same length. All routers in an area must have the same area address. All Level 2 routers must have a unique system ID domain-wide, and all Level 1 routers must have a unique system ID area-wide. 

Reference: http://www.cisco.com/en/US/products/ps6599/products_white_paper09186a00800a3e6f.sh tml 

Q9. What is a reason to use DHCPv6 on a network that uses SLAAC? 

A. To get a record of the IPs that are used by the clients 

B. To push DNS and other information to the clients 

C. No reason, because there is no need for DHCPv6 when using SLAAC 

D. Because DHCPv6 can be used only in stateful mode with SLAAC to record the IPs of the clients 

E. Because DHCPv6 can be used only in stateless mode with SLAAC to record the IPs of the clients 

F. Because DHCPv6 is required to use first-hop security features on the switches 

Answer:

Explanation: 

SLAAC is by far the easiest way to configure IPv6 addresses, simply because you don’t have to configure any IPv6 address. With SLAAC, a host uses the IPv6 Neighbor Discovery Protocol (NDP) to determine its IP address and default routers. Using SLAAC, a host requests and listens for Router Advertisements (RA) messages, and then taking the prefix that is advertised to form a unique address that can be used on the network. For this to work, the prefix that is advertised must advertise a prefix length of 64 bits (i.e., /64). But the most significant of Stateless Address Autoconfiguration (SLAAC) is it provided no mechanism for configuring DNS resolver information.Therefore SLACC can be used along with DHCPv6 (Stateless) to push DNS and other information to the clients. 

Q10. Which statement about BGP and diverse path advertisement is true? 

A. The BGP best-path selection must be disabled. 

B. The BGP best-path selection algorithm has been changed to always ignore the IGP metric. 

C. The BGP best-path selection algorithm has been changed so that two BGP paths can be flagged as best in the BGP table. 

D. The BGP best-path selection algorithm has not been changed. 

E. The BGP best-path selection is disabled for BGP routes for which the feature is enabled. 

Answer:

Explanation: 

The BGP Diverse Path Using a Diverse-Path Route Reflector feature allows BGP to distribute an alternative path other than the best path between BGP speakers when route reflectors are deployed. This additional path is added to the best-path, and the best path algorithm still remains unchanged.