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

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Q1. Which two statements about the client-identifier in a DHCP pool are true? (Choose two.) 

A. It specifies a unique identifier that is used only for DHCP requests. 

B. It is specified by appending 01 to the MAC address of a DHCP client. 

C. It specifies a hardware address for the client. 

D. It specifies a unique identifier that is used only for BOOTP requests. 

E. It requires that you specify the hardware protocol. 

Answer: A,B 

Reference: 

client-identifier unique-identifier 

Example: 

Device(dhcp-config)# client-identifier 01b7.0813.8811.66 

Specifies the unique identifier for DHCP clients. 

This command is used for DHCP requests. 

DHCP clients require client identifiers. You can specify the unique identifier for the client in either of the following ways: 

A 7-byte dotted hexadecimal notation. For example, 01b7.0813.8811.66, where 01 represents the Ethernet media type and the remaining bytes represent the MAC address of the DHCP client. 

A 27-byte dotted hexadecimal notation. For example, 7665.6e64.6f72.2d30.3032.342e.3937.6230.2e33.3734.312d.4661.302f.31. The equivalent ASCII string for this hexadecimal value is vendor-0024.97b0.3741-fa0/1, where vendor represents the vendor, 0024.97b0.3741 represents the MAC address of the source interface, and fa0/1 represents the source interface of the DHCP client. 

See the Troubleshooting Tips section for information about how to determine the client identifier of the DHCP client. 

Note 

The identifier specified here is considered for a DHCP client that sends a client identifier in the packet. 

Reference: http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_dhcp/configuration/15-mt/dhcp-15-mt-book/config-dhcp-server.html 

Q2. Which statement about a type 4 LSA in OSPF is true? 

A. It is an LSA that is originated by an ABR, that is flooded throughout the AS, and that describes a route to the ASBR. 

B. It is an LSA that is originated by an ASBR, that is flooded throughout the AS, and that describes a route to the ASBR. 

C. It is an LSA that is originated by an ASBR, that is flooded throughout the area, and that describes a route to the ASBR. 

D. It is an LSA that is originated by an ABR, that is flooded throughout the AS, and that describes a route to the ABR. 

E. It is an LSA that is originated by an ABR, that is flooded throughout the area, and that describes a route to the ASBR. 

Answer:

Explanation: 

LSA Type 4 (called Summary ASBR LSA) is generated by the ABR to describe an ASBR to routers in other areas so that routers in other areas know how to get to external routes through that ASBR. 

Q3. Refer to the exhibit. 

This network is configured with PIM, and the RPF check has failed toward the multicast source. Which two configuration changes must you make to router R3 to enable the RPF check to pass? (Choose two.) 

A. Configure a static multicast route to the multicast source through the tunnel interface. 

B. Configure a static multicast route to the multicast source LAN through the tunnel interface. 

C. Configure a static multicast route to the multicast source LAN through the Ethernet interface. 

D. Remove the command ip prim bidir-enable from the R3 configuration. 

Answer: A,B 

Q4. Which EEM event detector is triggered by hardware installation or removal? 

A. Enhanced-Object-Tracking Event Detector 

B. Resource Event Detector 

C. OIR Event Detector 

D. CLI Event Detector 

Answer:

Q5. Which statement about the NHRP network ID is true? 

A. It is sent from the spoke to the hub to identify the spoke as a member of the same NHRP domain. 

B. It is sent from the hub to the spoke to identify the hub as a member of the same NHRP domain. 

C. It is sent between spokes to identify the spokes as members of the same NHRP domain. 

D. It is a locally significant ID used to define the NHRP domain for an interface. 

Answer:

Explanation: 

The NHRP network ID is used to define the NHRP domain for an NHRP interface and differentiate between multiple NHRP domains or networks, when two or more NHRP domains (GRE tunnel interfaces) are available on the same NHRP node (router). The NHRP network ID is used to help keep two NHRP networks (clouds) separate from each other when both are configured on the same router. The NHRP network ID is a local only parameter. It is significant only to the local router and it is not transmitted in NHRP packets to other NHRP nodes. For this reason the actual value of the NHRP network ID configured on a router need not match the same NHRP network ID on another router where both of these routers are in the same NHRP domain. As NHRP packets arrive on a GRE interface, they are assigned to the local NHRP domain in the NHRP network ID that is configured on that interface. 

Reference: 

http://www.cisco.com/c/en/us/td/docs/ios/12_4/ip_addr/configuration/guide/hadnhrp.html 

Q6. Refer to the exhibit. 

You discover that only 1.5 Mb/s of web traffic can pass during times of congestion on the given network. 

Which two options are possible reasons for this limitation? (Choose two.) 

A. The web traffic class has too little bandwidth reservation. 

B. Video traffic is using too much bandwidth. 

C. The service-policy is on the wrong interface. 

D. The service-policy is going in the wrong direction. 

E. The NAT policy is adding too much overhead. 

Answer: A,B 

Explanation: 

In this example, the web traffic will fall into the default class, which is only 15 percent of the 10Mbps Internet connection (1.5Mbps). Meanwhile, video traffic is allowed 50% of the 10 Mbps. 

Q7. Which two statements about the metric-style wide statement as it applies to route redistribution are true? (Choose two.) 

A. It is used in IS-IS. 

B. It is used in OSPF. 

C. It is used in EIGRP. 

D. It is used for accepting TLV. 

E. It is used in PIM for accepting mroutes. 

F. It is used for accepting external routes. 

Answer: A,D 

Explanation: 

To configure a router running IS-IS to generate and accept only new-style TLVs (TLV stands for type, length, and value object), use the metric-style wide command. 

Reference: http://www.cisco.com/c/en/us/td/docs/ios/12_0s/feature/guide/TE_1208S.html#wp49409 

Q8. Refer to the exhibit. 

What does "(received-only)" mean? 

A. The prefix 10.1.1.1 can not be advertised to any eBGP neighbor. 

B. The prefix 10.1.1.1 can not be advertised to any iBGP neighbor. 

C. BGP soft reconfiguration outbound is applied. 

D. BGP soft reconfiguration inbound is applied. 

Answer:

Explanation: 

When you configure bgp soft-configuration-inbound, all the updates received from the neighbor will be stored unmodified, regardless of the inbound policy, and these routes appear as “(received-only).” 

Q9. According to RFC 4577, OSPF for BGP/MPLS IP VPNs, when must the down bit be set? 

A. when an OSPF route is distributed from the PE to the CE, for Type 3 LSAs 

B. when an OSPF route is distributed from the PE to the CE, for Type 5 LSAs 

C. when an OSPF route is distributed from the PE to the CE, for Type 3 and Type 5 LSAs 

D. when an OSPF route is distributed from the PE to the CE, for all types of LSAs 

Answer:

Explanation: 

If an OSPF route is advertised from a PE router into an OSPF area, the Down bit (DN) is set. Another PE router in the same area does not redistribute this route into iBGP of the MPLS VPN network if down is set. 

RFC 4577 says: 

“When a type 3 LSA is sent from a PE router to a CE router, the DN bit in the LSA Options field MUST be set. This is used to ensure that if any CE router sends this type 3 LSA to a PE router, the PE router will not redistribute it further. When a PE router needs to distribute to a CE router a route that comes from a site outside the latter’s OSPF domain, the PE router presents itself as an ASBR (Autonomous System Border Router), and distributes the route in a type 5 LSA. The DN bit [OSPF-DN] MUST be set in these LSAs to ensure that they will be ignored by any other PE routers that receive them.” 

For more information about Down bit according to RFC 4577 please read more herE. http://tools.ietf.org/html/rfc4577#section-4.2.5.1. 

Q10. On an MPLS L3VPN, which two tasks are performed by the PE router? (Choose two.) 

A. It exchanges VPNv4 routes with other PE routers. 

B. It typically exchanges iBGP routing updates with the CE device. 

C. It distributes labels and forwards labeled packets. 

D. It exchanges VPNv4 routes with CE devices. 

E. It forwards labeled packets between CE devices. 

Answer: A,C 

Explanation: 

MPLS VPN functionality is enabled at the edge of an MPLS network. The PE router performs these tasks: . 

Exchanges routing updates with the CE router . 

Translates the CE routing information into VPN version 4 (VPNv4) routes . 

Exchanges VPNv4 routes with other PE routers through the Multiprotocol Border Gateway Protocol (MP-BGP) 

A PE router binds a label to each customer prefix learned from a CE router and includes the label in the network reachability information for the prefix that it advertises to other PE routers. When a PE router forwards a packet received from a CE router across the provider network, it labels the packet with the label learned from the destination PE router. When the destination PE router receives the labeled packet, it pops the label and uses it to direct the packet to the correct CE router. Label forwarding across the provider backbone is based on either dynamic label switching or traffic engineered paths. A customer data packet carries two levels of labels when traversing the backbone 

Reference: http://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/asr9k_r4-2/lxvpn/configuration/guide/vcasr9kv342/vcasr9k42v3.html