Ch 3 - IPv6 Review and RIPng Flashcards
Which of the following is the shortest valid abbreviation for FE80:0000:0000:0000:0 010:0000:0000:0123?
a. FE80::10::123
b. FE8::1::123
c. FE80:0:0:0:10::123
d. FE80::10:0:0:123
D. Inside a quartet, any leading 0s can be omitted, and one sequence of one or more quartets of all 0s can be replaced with “::”. The correct answer replaces the longer three-quartet sequence of 0s with ::.
An ISP has assigned prefix 3000:1234:5678::/48 to Company1. Which of the following terms would typically be used to describe this type of public IPv6 prefix?
a. Subnet prefix
b. ISP prefix
c. Global routing prefix
d. Registry prefix
C. The name of the prefix generally represents the group to which the prefix is given, with the exception of the term global routing. IANA assigns a prefix to a registry (registry prefix). The registry can assign a subset of that range as a prefix to an ISP (ISP prefix). That ISP then subdivides that range of addresses into prefixes and assigns a prefix to one of its customers (site prefix, also called global routing prefix). The enterprise network engineers then further subdivide the range, often with prefix length 64, into subnet prefixes.
Which of the following answers list either a protocol or function that can be used by a host to dynamically learn its own IPv6 address? (Choose two.)
a. Stateful DHCP
b. Stateless DHCP
c. Stateless autoconfiguration
d. Neighbor Discovery Protocol
A and C. IPv6 supports stateful DHCP, which works similarly to IPv4’s DHCP to dynamically assign the entire IP address. Stateless autoconfiguration also allows for the assignment by finding the prefix from some nearby router and calculating the Interface ID using the EUI-64 format. Stateless DHCP simply supplies the DNS server IP addresses, and NDP supplies Layer 2 mapping information.
Which of the following is helpful to allow an IPv6 host to learn the IP address of a default gateway on its subnet?
a. Stateful DHCP
b. Stateless RS
c. Stateless autoconfiguration
d. Neighbor Discovery Protocol
D. Stateless auto-configuration only helps a host learn and form its own IP address, but it does not help the host learn a default gateway. Stateless RS is not a valid term or feature. Neighbor Discovery Protocol (NDP) is used for several purposes, including the same purpose as ARP in IPv4, plus to learn configuration parameters such as a default gateway IP address.
Which of the following answers lists a multicast IPv6 address?
a. 2000::1:1234:5678:9ABC
b. FD80::1:1234:5678:9ABC
c. FE80::1:1234:5678:9ABC
d. FF80::1:1234:5678:9ABC
D. Global unicast addresses begin with 2000::/3, meaning that the first 3 bits match the value in hex 2000. Similarly, unique local addresses match FD00::/8, and link-local addresses match FE80::/10 (values that begin with FE8, FE9, FEA, and FEB hex). Multicast IPv6 addresses begin FF00::/8, meaning that the first two hex digits are F.
Router R1 has two LAN interfaces and three serial interfaces enabled for IPv6. All the interfaces use link-local addresses automatically generated by the router. Which of the following could be the link-local address of R1’s interface S0/0?
a. FEA0::200:FF:FE11:0
b. FE80::200:FF:FE11:1111
c. FE80::0213:19FF:FE7B:0:1
d. FEB0::211:11FF:FE11:1111
B. When created automatically, link-local addresses begin FE80::/64, because after the prefix of FE80::/10, the device builds the next 54 bits as binary 0s. Statically assigned link-local addresses simply need to conform to the FE80::/10 prefix. As a result, only two answers are candidates with a beginning quartet of FE80. Of these, only one has only hex 0s in the second, third, and fourth quartets, making answer B the only valid answer.
Router R1 has the following configuration. Assuming that R1’s F0/0 interface has a MAC address of 0200.0011.1111, what IPv6 addresses will R1 list for interface F0/0 in the output of the show ipv6 interface brief command? (Choose two.)
interface f0/0 ipv6 address 2345:0:0:8::1/64
a. 2345:0:0:8::1
b. 2345:0:0:8:0:FF:FE11:1111
c. FE80::FF:FE11:1111
d. FE80:0:0:8::1
A and C. The ipv6 address command does not list an eui-64 parameter, so R1 does not form its global unicast address using the EUI-64 format. However, it does form its link-local address using EUI-64. The show ipv6 interface brief command lists both the global unicast and link-local addresses in its output.
Router R1 lists the following output from a show command. Which of the following is true about R1?
R1# show ipv6 interface f0/0 FastEthernet0/0 is up, line protocol is up
IPv6 is enabled, link-local address is FE80::213:19FF:FE12:3456
No Virtual link-local address(es):
Global unicast address(es):
2000::4:213:19FF:FE12:3456, subnet is 2000:0:0:4::/64 [EUI]
Joined group address(es):
FF02::1
FF02::2
FF02::1:FF12:3456
a. R1’s solicited node multicast address is FF02::1:FF12:3456.
b. R1’s 2000::4:213:19FF:FE12:3456 address is a global unicast with all 128 bits
statically configured.
c. Address FF02::2 is R1’s solicited node multicast.
d. R1’s solicited node multicast, not listed in this output, would be FF02::213:19FF:FE12:3456.
A. The group addresses listed in the output are the all IPv6 hosts address (FF02::1), the all IPv6 routers address (FF02::2), and the solicited node address that is based on R1’s global unicast address (FF02::1:FF12:3456). Also, R1’s global unicast address is listed correctly in answer B, but the “[EUI]” notation implies that R1 derived the interface ID portion using EUI-64 conventions.
Which of the following features work the same in both RIPv2 and RIPng? (Choose three.)
a. Distance Vector Logic
b. Uses UDP
c. Uses RIP-specific authentication
d. Maximum useful metric of 15
e. Automatic route summarization
A, B, and D. RIPv2 and RIPng both use UDP, both use distance-vector logic, and both use the same metric, with the same maximum (15) and same metric that means infinity (16). RIPng does not perform automatic route summarization because IPv6 has no concept of a classful network. RIPng also uses the built-in IPv6 authentication mechanisms rather than a RIP-specific authentication such as RIPv2.
Router R1 currently has no configuration related to IPv6 or IPv4. The following configuration exists in a planning document, intended to be used to copy/paste into Router R1 to enable RIPng and IPv6 on interfaces Fa0/0 and S0/0/0. No other related configuration exists. Which of the following is true about RIPng on R1 after this configuration has been pasted into R1?
ipv6 unicast-routing
interface fa0/0
ipv6 rip one enable
ipv6 address 2000::1/64
interface s0/0/0
ipv6 address 2001::/64 eui-64
ipv6 rip one enable
a. RIPng will be enabled on no interfaces.
b. RIPng will be enabled on one interface.
c. RIPng will be enabled on two interfaces.
d. RIPng will advertise about prefixes connected to S0/0/0 and Fa0/0, but only send Updates on one interface.
B. The fact that the configuration will be copied/pasted into a router means that the order of the commands matters. In this case, the fact that the ipv6 rip one enable command precedes the ipv6 address command on interface f0/0 means that Cisco IOS will reject the first of these commands, therefore not enabling RIPng on F0/0. The correct order listed under S0/0/0 means that RIPng will be enabled on S0/0/0. As a result, RIPng on R1 will advertise about S0/0/0’s connected IPv6 prefixes, and send Updates on S0/0/0, but will do nothing related for F0/0.
T/F: In IPv6 per packet overhead is reduced because routers do not need to recalculate header checksums.
True.
T/F: IPv6 headers have a field that easily identifies packets that are sent over the same TCP/UDP connection.
True. The Flow Label field IDs them.
T/F: Like IPv4, IPv6 supports unicast, multicast and broadcast.
False. IPv6 does not support broadcast.
T/F: IANA assigns addresses to ICANN who in turn hands them out to the RIRs who give them to ISPs.
False.The process of global address assignment of IPv6 address space is managed by IANA. IANA is is a function ofICANN, a nonprofit privateAmericancorporation that oversees globalIP addressallocation,autonomous systemnumber allocation,root zonemanagement in theDomain Name System(DNS),media types, and otherInternet Protocol-related symbols andInternet numbers. IANA assigns one or more IPv6 address ranges to each RIR who in turn assign prefixes to the ISPs.
How many RIRs are there? Name them.
- ARIN, AfriNIC, APNIC, LACNIC, RIPE-NCC
How many hex digits are there in an IPv6 address?
- Each hex digit is 4 bits for a total of 128 bits for an IPv6 address.
What are the two rules for shortening an IPv6 address?
- Omit leading zeroes in any given quartet of hex digits 2. Represent one or more consecutive quartets of all hex 0s with ::, but only once.
If a quartet is 4 hex digits, how many quartets in an IPv6 address?
8
Which of these are valid shortenings of this IPv6 address: FE00:0000:0000:0001:0000:0000:0000:0056. A. FE00::1:0:0:0:56 B. FE00:0:0:1:::56 C. Neither D. Both
D. Both are valid.
T/F: IPv6 is a classful style of addressing.
False. Prefixes are very similar to VLSM and CIDR
What is the prefix of: 2000:1234:5678:9ABC:1111:1234:5678:9ABC/64 (the network address)
2000:1234:5678:9ABC::/64
What is the prefix of: 2000:1234:5678:9ABC:1111:1234:5678:9ABC/56 (the network address)
2000:1234:5678:9A00::/56 The last 8 bits are zero because they are host bits and not part of the prefix. Host bits are always written as zero in a network address.
T/F: When writing an IPv6 prefix, any bits after the prefix length number of bits are zero.
True.
T/F: When writing an IPv6 prefix, if the prefix length is not on a quartet boundary, write down the value for the entire quartet.
True.
If you are assigned the routing prefix 2019:DEAD:BEEF/48 by your ISP and you want to use EUI-64 for address assignment, how large will your network prefix be? (The assigned routing prefix plus your subnet ID.) i.e. How many hex digits and how many subnets is that?
The combined network prefix is /64, 48 bits(12 hex digits) from the ISP assigned routing prefix, 16 bits (4 hex digits) for your subnets and 64 bits for hosts, which is a LOT of hosts per subnet.
T/F: A prefix cannot be abbreviated with the same rules as a full IPv6 address.
False. The same two rules can be applied.
Is 31AF::1234/3 a valid global unicast address?
Yes. The prefix reserved for global unicast addresses 2000::/3. This includes all IPv6 address where the first 3 bits are binary 001, or in hex the fist digit is either 2 or 3. Decimal 3 = 0011 in binary. The full address is: 31af:0000:0000:0000:0000:0000:0000:1234
What does 2340:1140::/26 mean?
This represents all addresses whose first 26 bits match the written hex number. Interestingly, the number of bits in the prefix does not break on a hex digit boundary. The third hex quartet is split down the middle. This is legal. Writing the last hex digit as zero is the correct version of the prefix notation. Omitting the trailing zero in the second quartet is incorrect, like: 2340:114::/26 (see page 82 in the text). This makes sense on a binary level if you break it down. Hex 4 = 0100 in binary, the 01 fall into the prefix bits, and the host bits are always 00, so 1140 is right. Hex 4 = 0100.
What is the prefix of 2340:1120::1/26 ?
2340:1100::/26. Look at the digits in binary, it makes sense. Hex 2 = 0010 in binary, the 0s fall into the prefix bits, and the host bits are always 00, so 1100 is right. Hex 0 = 0000
What is the prefix of 2340:1150::1/26 ?
2340:1140::/26 Look at the digits in binary, it makes sense. Hex 5 = 0101 in binary, 01 falls into the prefix side and the two host bits are 00, so 1140 is right. Hex 4 = 0100
What is the prefix of 2340:11FF::1/26?
2340:11c0::/26. Look at the digits in binary. It makes sense. Hex F = 1111 in binary, there are two 1s on the prefix side and two 0s on the host side. Hex C=1100.
In IPv6, Stateful DHCP supplies which of the following: A. IPv6 address B. DNS server address(s) C. Prefix length D. Default router
Stateful DHCP servers supply A, B and C. Clients use NDP to find their default router.
What is the IPv6 reserved range for multicast?
FF00::/8
What is the IPv6 multicast address for an unknown DHCP server?
FF02::1:2 or in long hand: FF02:0000:0000:0000:0000:0000:0001:0002
Which of the following can be learned by a host using SLAAC? A. Prefix B. Prefix Length C. Host ID D. Default router E. DNS server address(s)
SLAAC can provide all of these. SLAAC used NDP RS and RA msgs to learn prefix, prefix length and default router from a router on the local segment. EUI-64 provides the Interface ID. SLAAC relies on stateless DHCP to learn the IPv6 DNS server addresses.
Company A is assigned the global routing prefix 2340:1111:AAAA::/48 from it’s local ISP. What are the first four subnets (use 1,2,3,4) if a 16-bit subnet field is used with this site prefix?
2340:1111:AAAA:0001/64, 2340:1111:AAAA:0002/64, 2340:1111:AAAA:0003/64, 2340:1111:AAAA:0004/64.
Company A is assigned the global routing prefix 2340:1111:AAAA::/48 from it’s local ISP. You have decided that you need a lot of subnets. What are the first four subnets (use 1,2,3,4) if a 112-bit prefix is used?
2340:1111:AAAA::0001:0000/112, 2340:1111:AAAA::0002:0000/112, 2340:1111:AAAA::0003:0000/112, 2340:1111:AAAA::0004:0000/112,
T/F: in IPv6 each VLAN needs it’s own subnet.
True.
T/F: In IPv6 each serial link needs it’s own subnet.
True.
Which of the following global unicast address assignment methods is the default router learned from NDP? A. Stateful DHCP B. SLAAC C. Static assignment D. Static assignment with EUI-64
Actually, all of them. NDP RS and RA messages always supply the default router information to the hosts in IPv6.
Which of the following global unicast address assignment methods uses Stateless DHCP to provide the DNS server address(s)? A. Stateful DHCP B. SLAAC C. Static config D. Static config with EUI-64
B, C and D. All 3 of these methods rely on stateless DHCP to provide the DNS server address(s).