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

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Q1. Which three statements about GLBP are true? (Choose three.) 

A. It uses a virtual MAC address that starts with 0007.b4. 

B. It elects a single active virtual gateway to appoint and manage multiple active virtual forwarders. 

C. It allows the configured virtual IP address to be used on a physical interface as well. 

D. It uses a virtual MAC address that starts with 0070.4b. 

E. It elects multiple active virtual gateways to appoint and manage a single active virtual forwarder. 

F. Preemption is enabled for the configured active virtual gateway by default. 

Answer: A,B,C 

Explanation: 

The virtual MAC address in GLBP is 0007.b400.xxyy where xx is the GLBP group number and yy is the different number of each gateway (01, 02, 03…). One of the routers in a GLBP group is elected as an AVG – Active Virtual Gateway. There is only one active AVG in a group, and its task is to respond to ARP requests sent to the virtual gateway IP address replying different virtual MAC addresses in response packets. GLBP allows the configured virtual IP address to be used on a physical interface. By default, the GLBP gateway preemptive scheme is disabled. A backup virtual gateway can become the AVG only if the current AVG fails, regardless of the priorities assigned to the virtual gateways. 

Q2. Which two conditions must be met by default to implement the BGP multipath feature? (Choose two.) 

A. The next-hop routers must be the same. 

B. Route reflectors must be enabled. 

C. All attributes must have the same values. 

D. MPLS must be enabled. 

E. The next-hop routers must be different. 

Answer: C,E 

Q3. DRAG DROP 

Drag and drop the extended ping command field on the left to its usage on the right. 

Answer:  

Q4. Which two statements about OSPF route types are true? (Choose two.) 

A. The cost of an external type 2 route is the sum of the external and internal costs. 

B. The cost of an external type 2 route is the same as the external cost. 

C. Intra-area routes originate outside of their area. 

D. Inter-area routes originate inside their area. 

E. The cost of an external type 1 route is the same as the internal cost. 

F. For routes to the same destination, external type 1 routes are preferred over external type 2 routes. 

Answer: B,F 

Explanation: 

External routes fall under two categories, external type 1 and external type 2. The difference between the two is in the way the cost (metric) of the route is being calculated. The cost of a type 2 route is always the external cost, irrespective of the interior cost to reach that route. A type 1 cost is the addition of the external cost and the internal cost used to reach that route. A type 1 route is always preferred over a type 2 route for the same destination. 

Reference: http://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/7039-1.html 

Q5. In which two modes do IPv6-in-IPv4 tunnels operate? (Choose two.) 

A. tunnel mode 

B. transport mode 

C. 6to4 mode 

D. 4to6 mode 

E. ISATAP mode 

Answer: C,E 

Explanation: 

*There are 5 tunneling solution in IPv6:* 

*1. Using the “Tunnel mode ipv6ip”, in this case the tunnel source and destination are configured with IPv4 addressing and the tunnel interface is configured with IPv6. This will use protocol 41. This is used for IPv6/IPv4. 

R1(config)#int tunnel 1 

R1(config-if)#ipv6 address 12:1:12::1/64 

R1(config-if)#tunnel source 10.1.12.1 

R1(config-if)#tunnel destination 10.1.12.2 

R1(config-if)#*tunnel mode ipv6ip* 

*

2. Using the “Tunnel mode gre ipv6, in this case the tunnel source and destination are all configured with IPv6 addressing. This is used for IPv6/IPv6. 

BB1(config)#int tunnel 1 

BB1(config-if)#ipv6 address 121:1:121::111/64 

BB1(config-if)#tunnel source 10:1:111::111 

BB1(config-if)#tunnel destination 10:1:112::112 

BB1(config-if)#*tunnel mode gre ipv6* 

*3. 

In this case, the third type, the tunnel mode is NOT used at all, note that the tunnel interface is configured with IPv6 and the tunnel source and destination is configured with IPv4 but no mention of tunnel mode. This configuration will use protocol 47. This is used for IPv6/IPv4. 

R1(config)#int tunnel 13 

R1(config-if)#ipv6 address 13:1:13::1/64 

R1(config-if)#tunnel source 10.1.13.1 

R1(config-if)#tunnel destination 10.1.13.3 

*4. Note in this case a special addressing is assigned to the tunnel interface which is a concatenation of a reserved IPv6 address of 2002followed by the translated IPv4 address of a given interface on the router. In this configuration ONLY the tunnel source address is used and since the tunnel is automatic, the destination address is NOT configured. The tunnel mode is set to “Tunnel mode ipv6ip 6to4. Note the IPv4 address of 10.1.1.1 is translated to 0A.01.01.01 and once concatenated, it will be “2002:0A01:0101: or 2002:A01:101. This is used for IPv6/IPv4. 

R1(config)#interface Tunnel14 

R1(config-if)#ipv6 address 2002:A01:101::/128 

R1(config-if)#tunnel source 10.1.1.1 

R1(config-if)#*tunnel mode ipv6ip 6to4* 

*5. ISATAP, ISATAP works like 6to4 tunnels, with one major difference, it uses a special IPv6 address which is formed as follows: * 

*In this tunnel mode, the network portion can be any IPv6 address, whereas in 6to4 it had to start with 2002.* 

*Note when the IPv6 address is assigned to the tunnel interface, the “eui-64 is used, in this case the host portion of the IPv6 address starts with “0000.5EFE” and then the rest of the host portion is the translated IPv4 address of the tunnel’s source IPv4 address. This translation is performed automatically unlike 6to4. This is used for IPv6/IPv4.* 

R4(config)#int tunnel 46 

R4(config-if)#ipv6 address 46:1:46::/64 eui-64 

R4(config-if)#tunnel source 10.44.44.44 

R4(config-if)#*tunnel mode ipv6ip ISATAP* 

Q6. Which implementation can cause packet loss when the network includes asymmetric routing paths? 

A. the use of ECMP routing 

B. the use of penultimate hop popping 

C. the use of Unicast RPF 

D. disabling Cisco Express Forwarding 

Answer:

Explanation: 

When administrators use Unicast RPF in strict mode, the packet must be received on the interface that the router would use to forward the return packet. Unicast RPF configured in strict mode may drop legitimate traffic that is received on an interface that was not the router's choice for sending return traffic. Dropping this legitimate traffic could occur when asymmetric routing paths are present in the network. 

Reference: http://www.cisco.com/web/about/security/intelligence/unicast-rpf.html 

Q7. Refer to the exhibit. 

Which statement about the R1 configuration is true? 

A. It permits host 10.1.1.2 to establish a Telnet connection to R1. 

B. It limits remote hosts to two SSH connection attempts. 

C. SSH connections to R1 will log out after a 5-minute idle interval. 

D. Hosts that reside on network 10.0.0.0/8 can SSH to R1. 

E. The R1 timeout for outgoing SSH connection attempts is 30 seconds. 

Answer:

Explanation: 

The timeout for outgoing SSH connection is defined by the “ip sshh time-out” command (in seconds), which is configured here as 30. 

Q8. DRAG DROP 

Drag and drop the IPv6 multicast feature on the left to its corresponding function on the right. 

Answer:  

Q9. Refer to the exhibit. 

How many EIGRP routes will appear in the routing table of R2? 

A. 0 

B. 1 

C. 2 

D. 3 

Answer:

Explanation: 

EIGRPv6 on R2 was shut down so there is no EIGRP routes on the routing table of R2. If we turn on EIGRPv6 on R2 (with “no shutdown” command) then we would see the prefix of the loopback interface of R1 in the routing table of R2. 

Note. EIGRPv6 requires the “ipv6 unicast-routing” global command to be turned on first or it will not work. 

Q10. DRAG DROP 

Drag and drop the NHRP flag on the left to the corresponding meaning on the right. 

Answer: