Implementing Cisco Enterprise Advanced Routing and Services (ENARSI)
Exam Details
Exam Code
:300-410
Exam Name
:Implementing Cisco Enterprise Advanced Routing and Services (ENARSI)
Certification
:CCNP Enterprise
Vendor
:Cisco
Total Questions
:925 Q&As
Last Updated
:May 03, 2025
Cisco CCNP Enterprise 300-410 Questions & Answers
Question 601:
An automatic IPv4-compatible IPv6 tunnel exists between two IPv6 networks. The two IPv6 networks belong to different BGP autonomous systems (AS). The tunnel source has the IPv4 address 172.168.111.65/24 and the tunnel destination has the IPv4 address 172.168.222.80/24.
Which of the following statements is TRUE about the tunnel source and tunnel destination IPv6 addresses? (Choose two.)
A. the IPv6 address of the tunnel source is 172.168.111.65::
B. the IPv6 address of the tunnel source is ::172.168.111.65
C. the IPv6 address of the tunnel destination is 172.168.222.80::
D. the IPv6 address of the tunnel destination is ::172.168.222.80
Correct Answer: BD
The IPv6 address of the tunnel source is ::172.168.111.65 and the IPv6 address of the tunnel destination is
::172.168.222.80. These two addresses are IPv4-compatible IPv6 addresses, which are addresses that contain the IPv4 addresses of the tunnel source and destination.
In automatic IPv4-compatible IPv6 tunnel, the IPv4 addresses of the tunnel source and the tunnel destination are used to determine their IPv6 addresses. The IPv4 addresses of the tunnel source/destination are embedded into the least
significant 32 bits of an all-zero unicast IPv6 address. The resultant IPv6 address has zeros in the most significant 96 bits and the IPv4 address of the tunnel source/destination in the remaining 32 bits.
In this case, the source of an automatic IPv4-compatible IPv6 tunnel has the IPv6 address
0:0:0:0:0:0:172.168.111.65, abbreviated as ::2.168.111.65. You can also convert this address into pure hexadecimal format, which would be ACA8:6F41.
Any of the following three addresses could be used to identify the BGP neighbor at 172.168.11.65:
Similarly, the tunnel destination has the IPv6 address 0:0:0:0:0:0:172.168.222.80 (abbreviated as ::172.168.222.80). The hexadecimal form of the IPv6 address of the tunnel destination is ::ACA8:DE50.
Any of the following three addresses could be used to identify the BGP neighbor at 172.168.222.80:
The other two options state incorrect IPv6 addresses of the tunnel source and the tunnel destination. Both options specify an IPv6 address that has the IPv4 address of the tunnel source/destination in the most significant 32 bits and zeros in
the least significant 96 bits.
Objective:
Network Principles
Sub-Objective:
Recognize proposed changes to the network
References:
Home > Support > Technology Support > IP > IP Version 6 (IPv6) > Configure > Configuration Examples and Technotes > IPv6 Tunnel Through an IPv4 Network > Configure > Configurations (Automatic IPv4-Compatible Mode) Cisco IOS
IPv6 Implementation Guide > Implementing Tunneling for IPv6 Cisco > Support > Technology Support > IP > IP Version 6 (IPv6) > Technology Information > Technology White Paper > IPv6 Deployment Strategies > Selecting a Deployment
You have implemented IPv6 automatic 6-to-4 tunneling between three IPv6 subnets as shown in the network exhibit. (Click the Exhibit(s) button.)
You have used the following commands to implement the automatic 6-to-4 tunnel:
Your supervisor has assigned the task of verifying the automatic 6-to-4 tunnel to one of your colleagues. Your colleague runs the show running-config command and finds that incorrect IPv6 addresses have been assigned to the tunnel interfaces of the routers.
Which of the following IPv6 addresses should be assigned to rectify the problem? (Choose two.)
A. 2002::c0a8:2d01/64 to the Fa0/1 interface of rtrA
B. 2002:c0a8:4b01::1/64 to the Fa0/1 interface of rtrB
C. 2002:c0a8:7d01::1/64 to the Fa0/1 interface of rtrC
D. 2002:c0a8:4b01::1/64 to the Fa0/1 interface of rtrA
Correct Answer: BC
The 2002:c0a8:4b01::1/64 and the 2002:c0a8:7d01::1/64 IPv6 addresses should be assigned to the Fa0/1 interfaces of rtrB and rtrC, respectively. Automatic 6-to-4 tunnels embed the IPv4 address of the tunnel interfaces into the second and third quartets of the IPv6 address that has the 2002::/16 prefix.
To assign IPv6 addresses to the tunnel interfaces, perform the following steps:
1.
Convert the IPv4 address of the tunnel interface into binary.
2.
Convert the binary equivalent of the IPv4 address into hexadecimal (IPv6).
3.
Append the hexadecimal equivalent to the 2002::/16 prefix to form the IPv6 prefix of the tunnel interface.
For the Fa0/1 interface of rtrB, its IPv4 address of 192.68.75.1 is equivalent to the IPv6 address c0a8:4b01. This address is then appended to the 2002::/16 prefix, resulting in 2002:c0a8:4b01::/48. The remaining host bits can be filled with zeros. Similarly, the IPv4 address of the Fa0/1 interface of rtrC is converted to the IPv6 address 2002:c0a8:7d01::/48.
The 2002::c0a8:2d01/64 IPv6 address should not be assigned to the Fa0/1 interface of rtrA. The Fa0/1 interface of rtrA has the IPv4 address 192.168.45.1. The IPv6 equivalent of the IPv4 address, which is c0a8:2d01, should be embedded in the second and third quartets of the IPv6 address instead of the seventh and eighth quartets. IPv4 addresses are embedded into the last 32 bits for ISATAP tunnels.
The 2002:c0a8:4b01::1/64 IPv6 addresses should not be assigned to the Fa0/1 interface of rtrA. This IPv6 address is the equivalent of the IPv4 address 192.168.75.1, which is the address of the Fa0/2 interface of rtrB and not rtrA. Therefore,
this IPv6 address should be assigned to the Fa0/1 interface of rtrB.
Support > Technology Support > IP > IP Version 6 (IPV6) > Configure > Configuration Examples and Technotes > IPv6 Tunnel Through an IPv4 Network Cisco IOS IPv6 Implementation Guide, Release 15.2MandT > Implementing Tunneling for
IPv6
Question 603:
You have recently joined a company as the network administrator. You have been asked to complete the configuration on the border routers for an automatic 6-to-4 tunnel between several IPv6 network domains. The commands that are currently configured on the routers are as follows:
Which of the following additional commands is required to complete the configuration of automatic 6-to-4 tunnel on the border routers?
A. tunnel mode ipv6ip
B. tunnel mode ipv6ip 6to4
C. tunnel mode ipv6ip auto-tunnel
D. tunnel mode ipv6ip isatap
Correct Answer: B
The correct answer is to use the tunnel mode ipv6ip 6to4 command to complete the configuration of an automatic 6-to-4 tunnel. This command requires the use of IPv6 unicast addresses that have the 2002::/16 prefix.
The types of tunneling mechanisms supported by IPv6 are:
Automatic 6-to-4 tunnel
ISATAP tunnel
Manually configured tunnel
GRE tunnel
Apart from using a tunneling mechanism, interoperability between IPv4 and IPv6 can be provided by using a dual-stack infrastructure or Network Address Translation-Protocol Translation (NAT-PT). A dual-stack infrastructure allows you to
use both IPv4 and IPv6 addresses on the same router/host. NAT-PT is used to translate IPv4 addresses to IPv6 and vice versa.
The tunnel mode ipv6ip command should not be used to complete the configuration because this command specifies IPv6 as the passenger protocol and creates a manually configured tunnel.
The tunnel mode ipv6ip auto-tunnel command is not required to enable automatic 6-to-4 tunneling on the border routers. This command creates an automatic IPv4-compatible IPv6 tunnel between the routers.
The tunnel mode ipv6ip isatap command should not be used because this command creates an ISATAP tunnel.
You are the network administrator for a large software organization. You designed the LAN in the organization's main building for connecting the internal LAN to a WAN as shown below:
You have configured EIGRP with the variance parameter set to 3 on all the routers to enable unequal load balancing from the 172.16.1.0 network to the WAN. The delay configured on each of the routers is shown in the LAN diagram, and the K values are set as follows:
K1 = 0 K2 = 0 K3 = 1 K4 = 0 K5 = 0
Which of the following paths are entered into the routing tables as a result of the unequal load balancing configured on the routers? (Choose all that apply.)
A. RA-RB-RD-RH-RK
B. RA-RB-RE-RI-RK
C. RA-RC-RF-RI-RK
D. RA-RC-RG-RJ-RK
Correct Answer: B
The only path is entered in the routing table as a result of the unequal load balancing configured on the routers:
RA-RB-RE-RI-RK
In EIGRP networks, bandwidth and delay are the default factors for calculating the metric/cost for a given route. Additional factors such as load and reliability can be considered in the computation of the EIGRP metric, as given in the following
In this case, only the K3 value has a non-zero value. This implies that only delay is taken into consideration to calculate the metric of the shortest path from 172.16.1.0 network to the WAN. The path with the lowest metric, which is delay in this
scenario, is the shortest path, and is therefore entered automatically in the routing table. The total delay and the corresponding metric for the three best paths are given as follows:
In the given table, the path RA-RB-RE-RI-RK has the lowest metric of 14080. This is the shortest path, so it would be entered in the routing table even if variance were not enabled. In this scenario variance is set to 3, which enables unequal load balancing among those paths that have a metric less than three times the least metric for the given route. Three times the least metric in this scenario is 42240 (14080 x 3). This implies that paths between the 172.16.1.0 network and the WAN having a metric less than 42240 participate in the load balancing. On metric values alone, those paths would appear in the routing tables. However, to be eligible to be a feasible successor the reported distance of the path must be less than the feasible distance (current best path). None of the paths, with the exception of RA-RB-RE-RI-RK meet that requirement. The path RA-RB-RD-RH-RK is not entered in the routing table as a result of the unequal load balancing. The scaled EIGRP delay for this path is 43520 (170 x 256), which is more than three times the least metric available from the 172.16.1.0 network to the WAN (42240). In addition, the reported distance for this path is more than the feasible
distance. Therefore, the path RA-RB-RD-RH-RK is not used for balancing the load from the 172.16.1.0 network to the WAN and does not appear in the routing tables.
Objective:
Layer 3 Technologies
Sub-Objective:
Configure and verify EIGRP load balancing
References:
Cisco > Support > Technology Support > IP > IP Routing > Design > Design Technotes > How Does Unequal Cost Path Load Balancing (Variance) Work in IGRP and EIGRP? > Document ID: 13677 Cisco > Support > Technology Support >
IP > IP Routing > Design > Design Technotes > How Does Load Balancing Work? > Document ID: 5212
Cisco > Support > Technology Support > IP > IP Routing > Technology Information > Technology Whitepaper > Enhanced Interior Gateway Routing Protocol > Document ID: 16406 > Feasible Distance, Reported Distance, and Feasible
Successor
Question 605:
Automatic 6-to-4 tunnels exist between dual-stack routers (A, B, and C). One router has the IPv6 address, 2002:D030:6BC0:173C::26:37D0/48
Which of the following addresses is the IPv4 address of the router with the IPv6 address 2002:D030:6BC0:173C::26:37D0/48?
A. 10.176.15.131
B. 10.200.80.67
C. 208.48.107.192
D. 208.138.16.110
Correct Answer: C
The IPv4 address of the IPv6 router is 208.48.107.192. In an automatic 6-to-4 tunnel, IPv6 addresses have the 2002::/16 prefix. The 32-bit IPv4 address of the IPv6 router is then embedded into the IPv6 address. The 32 bits of the IPv4 address is embedded in the second and third quartet of the IPv6 address. The second and third quarters in the IPv6 address correspond to D030:6BC0. The conversion of these hexadecimal digits into decimal is given as follows:
The IPv6 router does not have 10.176.15.131 as its IPv4 address. The 10.176.15.131 address is the IPv4 equivalent of the second and third quarter (05B0:0F81) in the source IPv6 address.
The other two IPv4 addresses are incorrect as they pertain to neither of the two IPv6 hosts.
Objective:
Network Principles
Sub-Objective:
Recognize proposed changes to the network
References:
Cisco IOS IPv6 Implementation Guide > Implementing Tunneling for IPv6
Question 606:
You need to manually assign IPv6 addresses to the interfaces on an IPv6-enabled router. While assigning addresses, you need to ensure that the addresses participate in neighbor discovery and in stateless auto- configuration process on a physical link.
Which of the following addresses can be assigned to the interfaces?
A. FEC0:0:0:1::1/64
B. FE80::260:3EFF:FE11:6770/10
C. 2001:0410:0:1:0:0:0:1/64
D. 2002:500E:2301:1:20D:BDFF:FE99:F559/64
Correct Answer: B
The FE80::260:3EFF:FE11:6770/10 address can be assigned to an interface of the IPv6-enabled router. This address is a link-local address as it has the prefix FE80::/10. Link-local addresses can be configured for an interface either
automatically or manually.
Link-local addresses are IPv6 unicast addresses that are configured on the interfaces of an IPv6-enabled router. With link-local addresses, the nodes can connect to a network (local link) and communicate with other nodes. In addition, these
addresses participate in the neighbor discovery protocol and the stateless auto- configuration process.
The FEC0:0:0:1::1/64 address should not be used for the interfaces because this address is a site-local address. Site-local addresses are IPv6 equivalent addresses to IPv4's private address classes. These addresses are available only
within a site or an intranet, which typically is made of several network links.
You should not use the 2001:0410:0:1:0:0:0:1/64 and 2002:500E:2301:1:20D:BDFF:FE99:F559 addresses for the interfaces. These two addresses are global unicast addresses as they fall in the range from 2000::/3 and to E000::/3. A global
address is used on links that connect organizations to the Internet service providers (ISPs).
Objective:
Layer 3 Technologies
Sub-Objective:
Identify IPv6 addressing and subnetting
References:
Cisco > Understanding IPv6 Link Local Address
Question 607:
OSPF area border routers (ABRs) advertise a default route to stub and totally stubby areas.
Which command is the BEST command to configure a cost of 25 for the default route advertised to area 1?
A. Router(config-router)# area 1 cost 25
B. Router(config-router)# area 1 default 25
C. Router(config-router)# area 1 default-cost 25
D. Router(config-router)# area 1 default-route-cost 25
Correct Answer: C
The correct answer is area 1 default-cost 25. Even though another option (area 1 default 25) is a configurable abbreviation for the command, the more correct answer explicitly specifies the default-cost parameter. The correct syntax for the area default-cost command is shown below:
Router(config-router)# area area-id default-cost cost
If you have multiple border routers between two areas, you might prefer one exit-point router over the other for that area. By configuring one with a lower cost than the other, it will become the preferred exit point. If that router or its links were to fail, then the routers interior to the area would route through the second-best exit point. You could also set the default costs to values that are close to achieve better load balancing. The default default-cost is 1. Please see the network shown in the graphic.
Objective:
Layer 3 Technologies
Sub-Objective:
Configure and verify OSPF path preference
References:
Cisco IOS Master Command List, Release 12.4 > a through b > area default-cost
Question 608:
You have a router that is running both OSPF and RIP. You have configured this router to perform mutual redistribution between the two protocols. The following conditions exist: The S0/0 interface, which is configured for RIP, is routing for the 172.16.5.0/24 network. The S0/1 interface, which is configured for OSPF, is routing for the 172.16.6.32/28 network.
Users in the RIP domain are unable to connect to devices in the OSPF domain.
What must be done to allow the OSPF routes to be redistributed into the RIP domain? (Choose two. Each correct answer is part of the solution.)
A. Create a static route that points to 172.16.6.0/24 with a next hop of null0.
B. Execute the passive-interface command on S0/0.
C. Create a loopback address on the router
D. Redistribute static routes into RIP.
Correct Answer: AD
The OSPF domain has a different mask than the RIP domain, and they are on the same major network. The OSPF domain's mask is also longer than the RIP domain's mask. Therefore, the RIP domain will not advertise routes learned from
OSPF and redistributed into RIP. To solve this problem, you can create a static route to the major (classful) network 172.16.6.0/24, which includes all of the subnets in the OSPF domain, set the destination as null0, and then redistribute static
routes into RIP. The following commands would enable this process:
router1(config)# ip route 172.16.5.0 255.255.255.0 null0
router1(config)# router rip
router1(config-router)# redistribute static
router1(config-router)# default metric 1
You should include the metric as well to ensure redistribution. This will allow the 172.16.5.0/24 network to be advertised to the RIP domain and, when the frames arrive at the null0 interface, will ensure the routing table of the router will have
routes to the specific subnets of the OSPF domain.
You should not execute the passive-interface command. This would prevent the interface from advertising either RIP or OSPF routes, and would only allow RIP updates inbound. This would not solve the problem and will create additional
problems when the router is unable to advertise RIP routes to the other routers in the RIP domain.
You should not create a loopback address on the router. Loopback addresses are logical addresses that can be created and used as the source of routing updates. Under normal circumstances, if routing updates are sourced from a physical
interface and the interface goes down, the route will be removed from the routing tables. Since a loopback interface cannot go down, it provides the advantage of keeping a route in the tables even if the physical interface that services the
route goes down. Loopback interfaces are of no help in solving the redistribution problem.
Objective:
Layer 3 Technologies
Sub-Objective:
Configure and verify manual and autosummarization with any routing protocol
References:
Cisco > Home > Support > Technology Support > IP > IP Routing > Design > Design Technotes > Redistributing Between Classful and Classless Protocols: EIGRP or OSPF into RIP or IGRP
Question 609:
Examine the exhibit by pressing the Exhibit(s) button.
You are to configure R1 to belong to area 5. This area does not accept routes from the external AS or summary routes from any other internal areas. Refer to the IP addressing below.
R1 - int E0 - 192.168.5.1/24 R2 - int E0 - 192.168.5.2/24 R2 - int E1 - 192.168.0.2/24 R3 - int E0 - 192.168.0.3/24
Which configuration commands are required to correctly configure R1?
A. R1(config)# router ospf 10 R1(config-router)# area 5 no-summary stub R1(config-router)# network 192.168.5.0 0.0.0.255 area 5
B. R1(config)# router ospf 5 R1(config-router)# area 5 stub R1(config-router)# network 192.168.5.0 0.0.0.255 area 5
C. R1(config)# router ospf 10 R1(config-router)# area 5 stub R1(config-router)# network 192.168.5.0 255.255.255.0 area 5
D. R1(config)# router ospf 5 R1(config-router)# area 5 stub no-summary R1(config-router)# network 192.168.5.0 255.255.255.0 area 5
Correct Answer: B
All routers within a stub area must be configured as stub, or adjacencies will not form. Besides the command to enable OSPF and the command to identify the area, the only other required command identifies the area as a stub. At the area border router (ABR), R2, the no-summary keyword is required. The following commands are required to configure R1:
R1(config)# router ospf 5 R1(config-router)# area 5 stub R1(config-router)# network 192.168.5.0 0.0.0.255 area 5
A totally stubby area does not accept any external network LSAs (Type 5) or any inter-area summary LSAs (Types 3 and 4) from entering the area. Use the area stub command with the no-summary keyword on the ABR only to configure a totally stubby area.
The correct syntax for the area stub command is shown below:
Router(config-router)# area area-id stub [no-summary]
Note that the optional no-summary keyword is used only on ABRs to block summary link advertisements into the stub area. This option creates a totally stubby area. It is very important to configure the command consistently on all routers within the area. OSPF sends its stub status (on or off) in its hello packets.
If two neighbors have conflicting stub status, they will not form an adjacency, and you end up with no OSPF communication over that link.
Objective:
Layer 3 Technologies
Sub-Objective:
Configure and verify network types, area types, and router types
References:
Cisco > Home > Support > Technology Support > IP Routing > Design > Design Technotes > What Are OSPF Areas and Virtual Links? > What Are Areas, Stub Areas, and Not-So-Stubby Areas? Cisco IOS Master Command List, Release
12.4 > a through b > area stub
Question 610:
Which of the following commands will display information about Type 4 LSAs?
A. show ip ospf database external
B. show ip ospf database asbr-summary
C. show ip ospf database summary
D. show ip ospf database router
Correct Answer: B
The command show ip ospf database asbr-summary will display information about Type 4 LSAs. These LSAs provide next-hop information for areas that are receiving Type 5 or external LSAs. Consider the following sample output of the show ip ospf database asbr-summary command: The output shows that the router that sent this LSA is at 172.16.241.75. The router functioning as the ASBR is at 172.16.245.63. The advertising router, located at 172.16.241.75, is broadcasting that its best metric to reach the ASBR at
172.16.254.63 is 1.
The command show ip ospf database external will not display information about Type 4 LSAs. It will display information about Type 5 LSAs, or External Link LSAs, instead of ASBR summary links, which are Type 4 LSAs.
The command show ip ospf database summary will not display information about Type 4 LSAs. It will display information about summary links, or Type 3 LSAs, that are generated by an ABR, not summary links generated by an ASBR.
The command show ip ospf database router will not display information about Type 4 LSAs. It will display information about router links, or Type 1 LSAs, instead of ASBR summary links, which are Type 4 LSAs.
Objective:
Layer 3 Technologies
Sub-Objective:
Describe OSPF packet types
References:
Cisco > Cisco IOS IP Routing: OSPF Command Reference > show ip ospf database
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