Q1. Which type of BGP AS number is 64591?
A. a private AS number
B. a public AS number
C. a private 4-byte AS number
D. a public 4-byte AS number
Answer: A
Explanation:
Q2. A network engineer is trying to implement broadcast-based NTP in a network and executes the ntp broadcast client command. Assuming that an NTP server is already set up, what is the result of the command?
A. It enables receiving NTP broadcasts on the interface where the command was executed.
B. It enables receiving NTP broadcasts on all interfaces globally.
C. It enables a device to be an NTP peer to another device.
D. It enables a device to receive NTP broadcast and unicast packets.
Answer: A
Explanation:
The NTP service can be activated by entering any ntp command. When you use the ntp broadcast client
command, the NTP service is activated (if it has not already been activated) and the device is configured to receive NTP broadcast packets on a specified interface simultaneously.
Command Description
ntp broadcast Allows the system to receive NTP broadcast packets on an client interface.
Reference: http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/bsm/command/bsm-xe-3se-3850- cr-book/
bsm-xe-3se-3850-cr-book_chapter_00.html
Q3. A network engineer is investigating the cause of a service disruption on a network segment and executes the debug condition interface fastethernet f0/0 command. In which situation is the debugging output generated?
A. when packets on the interface are received and the interface is operational
B. when packets on the interface are received and logging buffered is enabled
C. when packets on the interface are received and forwarded to a configured syslog server
D. when packets on the interface are received and the interface is shut down
Answer: A
Explanation:
Q4. What is the purpose of the autonomous-system {autonomous-system-number} command?
A. It sets the EIGRP autonomous system number in a VRF.
B. It sets the BGP autonomous system number in a VRF.
C. It sets the global EIGRP autonomous system number.
D. It sets the global BGP autonomous system number.
Answer: A
Explanation:
To configure the autonomous-system number for an Enhanced Interior Gateway Routing
Protocol (EIGRP) routing process to run within a VPN routing and forwarding (VRF) instance, use the
autonomous-system command in address-family configuration mode. To remove the autonomous-system
for an EIGRP routing process from within a VPN VRF instance, use the no form of this command.
autonomous-system autonomous-system-number no autonomous-system autonomous-system-number
Reference: http://www.cisco.com/c/en/us/td/docs/ios/iproute_eigrp/command/reference/ire_book/
ire_a1.htm l#wp1062796
Q5. A network engineer executes the “ipv6 flowset” command. What is the result?
A. Flow-label marking in 1280-byte or larger packets is enabled.
B. Flow-set marking in 1280-byte or larger packets is enabled.
C. IPv6 PMTU is enabled on the router.
D. IPv6 flow control is enabled on the router.
Answer: A
Explanation:
Enabling Flow-Label Marking in Packets that Originate from the Device This feature allows the device to
track destinations to which the device has sent packets that
are 1280 bytes or larger.
SUMMARY STEPS
1.enable
2.configure terminal
3.ipv6 flowset
4.exit
5.clear ipv6 mtu
DETAILED STEPS
Command or Action Purpose
Step 1 enable Enables privileged EXEC mode.
Enter your password if prompted.
Example:
Device> enable
Step 2 configure terminal Enters global configuration mode.
Example:
Device# configure
terminal
Step 3 ipv6 flowset Configures flow-label marking in 1280-byte or larger packets sent by the device.
Example:
Device# configure
terminal
Step 3 ipv6 flowset Configures flow-label marking in 1280-byte or larger packets sent by the device.
Example:
Device(config)# ipv6
flowset
Reference: http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipv6_basic/configuration/15- mt/ip6b-15-mtbook/ip6-mtu-path-disc.html
Q6. Which two methods of deployment can you use when implementing NAT64? (Choose two.)
A. stateless
B. stateful
C. manual
D. automatic
E. static
F. functional
G. dynamic
Answer: A,B
Explanation:
While stateful and stateless NAT64 perform the task of translating IPv4 packets into IPv6 packets and vice
versa, there are important differences. The following
table provides a high-level overview of the most relevant differences.
Table 2. Differences Between Stateless NAT64 and Stateful NAT64
Stateless NAT64 Stateful NAT64
1:1 translation 1:N translation
No conservation of IPv4 address Conserves IPv4 address
Assures end-to-end address Uses address overloading, hence transparency and scalability lacks in endto-
end address transparency
No state or bindings created on the State or bindings are created on every translation unique translation
Requires IPv4-translatable IPv6 No requirement on the nature of IPv6 addresses assignment (mandatory
address assignment requirement)
Requires either manual or DHCPv6 Free to choose any mode of IPv6 based address assignment for IPv6
address assignment viz. Manual, hosts DHCPv6, SLAAC Reference: http://www.cisco.com/c/en/us/
products/collateral/ios-nx-os-software/enterprise-ipv6- solution/white_paper_c11-676277.html
Q7. A packet capture log indicates that several router solicitation messages were sent from a local host on the IPv6 segment. What is the expected acknowledgment and its usage?
A. Router acknowledgment messages will be forwarded upstream, where the DHCP server will allocate addresses to the local host.
B. Routers on the IPv6 segment will respond with an advertisement that provides an external path from the local subnet, as well as certain data, such as prefix discovery.
C. Duplicate Address Detection will determine if any other local host is using the same IPv6 address for communication with the IPv6 routers on the segment.
D. All local host traffic will be redirected to the router with the lowest ICMPv6 signature, which is statically defined by the network administrator.
Answer: B
Explanation:
Router Advertisements (RA) are sent in response to router solicitation messages. Router
solicitation messages, which have a value of 133 in the Type field of the ICMP packet header, are sent by
hosts at system startup so that the host can immediately autoconfigure without needing to wait for the next
scheduled RA message. Given that router solicitation messages are usually sent by hosts at system
startup (the host does not have a configured unicast address), the source address in router solicitation
messages is usually the unspecified IPv6 address (0:0:0:0:0:0:0:0). If the host has a configured unicast
address, the unicast address of the interface sending the router solicitation message is used as the source
address in the message. The destination address in router solicitation messages is the all-routers multicast
address with a scope of the link. When an RA is sent in response to a router solicitation, the destination
address in the RA message is the unicast address of the source of the router solicitation message. RA
messages typically include the following information:
One or more onlink IPv6 prefixes that nodes on the local link can use to automatically configure their IPv6
addresses
Lifetime information for each prefix included in the advertisement
Sets of flags that indicate the type of autoconfiguration (stateless or stateful) that can be completed
Default router information (whether the router sending the advertisement should be used as a default
router and, if so, the amount of time (in seconds) the router should be used as a default router)
Additional information for hosts, such as the hop limit and MTU a host should use in packets that it
originates Reference: http://www.cisco.com/c/en/us/td/docs/ios/ipv6/configuration/guide/12_4t/
ipv6_12_4t_book/ip6- addrg_bsc_con.html
Q8. After you review the output of the command show ipv6 interface brief, you see that several IPv6 addresses have the 16-bit hexadecimal value of "FFFE" inserted into the address. Based on this information, what do you conclude about these IPv6 addresses?
A. IEEE EUI-64 was implemented when assigning IPv6 addresses on the device.
B. The addresses were misconfigured and will not function as intended.
C. IPv6 addresses containing "FFFE" indicate that the address is reserved for multicast.
D. The IPv6 universal/local flag (bit 7) was flipped.
E. IPv6 unicast forwarding was enabled, but IPv6 Cisco Express Forwarding was disabled.
Answer: A
Explanation:
Extended Unique Identifier (EUI), as per RFC2373, allows a host to assign iteslf a unique 64-
Bit IP Version 6 interface identifier (EUI-64). This feature is a key benefit over IPv4 as it eliminates the
need of manual configuration or DHCP as in the world of IPv4. The IPv6 EUI-64 format address is obtained
through the 48-bit MAC address. The Mac address is first separated into two 24-bits, with one being OUI
(Organizationally Unique Identifier) and the other being NIC specific. The 16-bit 0xFFFE is then inserted
between these two 24-bits to for the 64-bit EUI address. IEEE has chosen FFFE as a reserved value which
can only appear in EUI-64 generated from the an EUI-48 MAC address. Here is an example showing how
a the Mac Address is used to generate EUI.
Next, the seventh bit from the left, or the universal/local (U/L) bit, needs to be inverted. This bit identifies whether this interface identifier is universally or locally administered. If 0, the address is locally
administered and if 1, the address is globally unique. It is worth noticing that in the OUI portion, the globally
unique addresses assigned by the IEEE has always been set to 0 whereas the locally created addresses
has 1 configured. Therefore, when the bit is inverted, it maintains its original scope (global unique address
is still global unique and vice versa). The reason for inverting can be found in RFC4291 section 2.5.1.
Once the above is done, we have a fully functional EUI-64 format address.
Reference: https://
supportforums.cisco.com/document/100566/understanding-ipv6-eui-64-bit- address
Q9. Refer to the exhibit.
Which statement is true?
A. Traffic from the 172.16.0.0/16 network will be blocked by the ACL.
B. The 10.0.0.0/8 network will not be advertised by Router B because the network statement for the 10.0.0.0/8 network is missing from Router B.
C. The 10.0.0.0/8 network will not be in the routing table on Router B.
D. Users on the 10.0.0.0/8 network can successfully ping users on the 192.168.5.0/24 network, but users on the 192.168.5.0/24 cannot successfully ping users on the 10.0.0.0/8 network.
E. Router B will not advertise the 10.0.0.0/8 network because it is blocked by the ACL.
Answer: E
Explanation:
Q10. The following configuration is applied to a router at a branch site:
ipv6 dhcp pool dhcp-pool
dns-server 2001:DB8:1:B::1
dns-server 2001:DB8:3:307C::42
domain-name example.com
!
If IPv6 is configured with default settings on all interfaces on the router, which two dynamic IPv6 addressing mechanisms could you use on end hosts to provide end-to-end connectivity? (Choose two.)
A. EUI-64
B. SLAAC
C. DHCPv6
D. BOOTP
Answer: A,B
Explanation: