Ipv6 Overview Flashcards
What is the global routing prefix in IPv6?
The prefix assigned by the provider to a customer or site, varying by ISP policies.
What does the Subnet ID field in an IPv6 address indicate?
It identifies subnets within an organization.
What is the Interface ID in an IPv6 address?
Equivalent to the host portion of an IPv4 address, typically using a /64 subnet.
True or False: The all-0s IPv6 address can be assigned to any device.
False. The all-0s address is reserved as a Subnet-Router anycast address.
What are IPv6 global unicast addresses (GUAs)?
Globally unique addresses routable on the IPv6 internet.
Fill in the blank: IPv6 GUAs currently begin with the first three bits of ______.
001 or 2000::/3.
What is the range for IPv6 unique local addresses?
fc00::/7 to fdff::/7.
What is the primary use of unique local addresses (ULAs)?
For local addressing within a site or between limited sites.
What are the two types of unicast addresses typically assigned to IPv6 devices?
- Global Unicast Address (GUA)
- Link-local Address (LLA)
True or False: Link-local addresses (LLAs) can be routed.
False. LLAs are confined to a single link and cannot be routed.
What is the range of IPv6 link-local addresses (LLAs)?
fe80::/10.
What command is used to configure a static GUA on a router interface?
ipv6 address ipv6-address/prefix-length.
What is the recommended prefix length for IPv6 networks?
/64.
What are the three categories of IPv6 addresses?
- Unicast
- Multicast
- Anycast
What does unicast mean in the context of IPv6?
It uniquely identifies an interface on an IPv6-enabled device.
What is the purpose of Router Solicitation (RS) messages?
To discover IPv6 routers.
What information can Router Advertisement (RA) messages provide?
- Network prefix and prefix length
- Default gateway address
- DNS addresses and domain name
What does SLAAC stand for?
Stateless Address Autoconfiguration.
What is the maximum number of /64 subnets that can be created from a /48 global routing prefix?
65,536.
Fill in the blank: IPv6 addresses are represented in ______ format.
hexadecimal.
What is the preferred format for writing an IPv6 address?
x:x:x:x:x:x:x:x, with each ‘x’ consisting of four hexadecimal values.
What is the rule for omitting leading zeros in IPv6 addresses?
Leading 0s can be omitted, but trailing 0s must not be omitted.
What does a double colon (::) represent in IPv6 addresses?
It can replace a contiguous string of one or more 16-bit hextets consisting of all zeros.
What is the purpose of Dynamic Host Configuration Protocol for IPv6 (DHCPv6)?
To provide additional network information such as DNS server addresses.
True or False: IPv4 and IPv6 will coexist for the foreseeable future.
True.
What are the three migration techniques for transitioning from IPv4 to IPv6?
- Dual stack
- Tunneling
- Translation
What are the three categories of migration techniques to IPv6?
Dual stack, tunneling, translation
These techniques facilitate the transition from IPv4 to IPv6.
What is the length of an IPv6 address?
128 bits
What is the preferred format for writing an IPv6 address?
x:x:x:x:x:x:x:x
How many hexadecimal values does each ‘x’ in an IPv6 address consist of?
Four
What are the three types of IPv6 addresses?
- Unicast
- Multicast
- Anycast
What does an IPv6 unicast address do?
Uniquely identifies an interface on an IPv6-enabled device
What is an IPv6 global unicast address (GUA)?
Globally unique and routable on the IPv6 internet
What is the purpose of an IPv6 link-local address (LLA)?
Enables communication with other IPv6-enabled devices on the same link
What command is used to configure an IPv6 GUA on an interface?
ipv6 address ipv6-address/prefix-length
How does a device obtain a GUA dynamically?
Through ICMPv6 messages
How often do IPv6 routers send out ICMPv6 RA messages?
Every 200 seconds
What are the three methods of RA messages?
- SLAAC
- SLAAC with a stateless DHCPv6 server
- Stateful DHCPv6 (no SLAAC)
What processes can be used to create the interface ID in IPv6?
- EUI-64 process
- Randomly generated 64-bit number
What is the EUI-64 process?
Uses the 48-bit Ethernet MAC address to create a 64-bit interface ID
What happens if a device uses a randomly generated interface ID?
It may differ depending upon the operating system
Is it mandatory for all IPv6 devices to have an IPv6 LLA?
Yes
How can an LLA be created?
Manually or dynamically
What are the two types of IPv6 multicast addresses?
- Well-known multicast addresses
- Solicited node multicast addresses
What is the All-nodes multicast group address?
ff02::1
What is the All-routers multicast group address?
ff02::2
What is a solicited-node multicast address?
Similar to the all-nodes multicast address, mapped to a special Ethernet multicast address
What is the purpose of the subnet ID field in an IPv6 GUA?
Used to create subnets
What is stateful DHCPv6?
A method for a device to automatically receive a GUA, prefix length, and DNS server addresses
What does the RA message suggest for devices?
- Use router LLA for default gateway
- Use stateful DHCPv6 server for GUA and DNS server address
What is the value inserted in the EUI-64 process?
A 16 bit value of fffe
What happens to the 7th bit of the client MAC address in the EUI-64 process?
It is reversed from binary 0 to 1
What is Duplicate Address Detection (DAD)?
A process to ensure the uniqueness of any IPv6 unicast address
How are dynamic LLAs created?
Using the fe80::/10 prefix and the interface ID
What is the default method Cisco IOS routers use to generate the interface ID for LLAs?
EUI-64
What is the IPv6 address format for a dynamically configured LLA on Cisco routers?
fe80:: followed by the EUI-64 generated interface ID
What is the command to check the IPv6 interface configuration on Cisco routers?
show ipv6 interface brief
What are link local address (LLA)
Required for every IPv6-enabled device and used to communicate with other devices on the same local link. LLAs are not routable and are confined to a single link.
