Introducing Basic IPv6 Flashcards
What are the main characteristics of an IPv6 address? (# of bits, masking, etc.)
How do you shorten an IPv6 address?
128 bits, divided into 8 “hextets” of 16bits each (4 characters)
- Leading 0’s in each hextet can be omitted, leaving a single 0 if it’s all 0’s
- Successive 0 hextets can be represented as “::” but only once in an address
NOTE: Lower case letters are recommended.
(example: 2001:0db8:010f:0001:0000:0000:0000:0acd > 2001:db8:10f:1:0:0:0:acd > 2001:db8:10f:1::acd)
What BASE # is hexadecimal?
BASE 16
(0 - 15)
What letters are used in hexadecimal and what is the binary equivalent to each?
A - F are used in place of 10 - 15.
A = 10th value = 1010
B = 11th value = 1011
C = 12th value = 1100
D = 13th value = 1101
E = 14th value = 1110
F = 15th value = 1111
What is the IPv6 loopback address?
::1 /128
(or 0:0:0:0:0:0:0:1 /128)
What is an unspecified IPv6 address?
If the device doesn’t have an address yet and it is wanting a DHCP address, it would send out a request with it’s source as an unspecified address. (Similar to an ‘unknown address’ in IPv4 of 0.0.0.0)
Binary = 0000…000
IPv6 = ::/128
What is a Global Unicast IPv6 address?
Similar to an IPv4 public IP address, because they are unique in the world. Assigned by IANA (Internet Assigned Numbers Authority) and used on public networks. ISPs summarize to provide scalability on the internet.
Binary - 001… (first three bits locked)
IPv6 - 2000::/3 (2000 - 3fff)
What is a link-local unicast IPv6 address?
Every IPv6 device gets a link-local address, that way they can communicate even if all other means of addressing (DHCP, etc.) breaks down. A link-local address is required for all interfaces that have physical links.
When routers for neighbors, they use the link-local address for IPv6.
Binary - 1111 1110 10…. (first ten bits locked in)
IPv6 - FE80::/10
NOTE - Typically link-local start with fe80, but can also include addresses beginning with anything from fe80 - febf.
What is a unique-local unicast IPv6 address?
They are the same as a private IPv4 address and are used for local communications, the scope is the entire site or organization.
IPv6 - fc00::/7
What is a Multicast IPv6 address?
No broadcast address in IPv6, but some of the multicast groups are very much like the IPv4 broadcast addresses. Depending on the type of device, it will start automatically joining different Multicast groups. You can use a multicast addresses across multiple subnets.
Binary - 1111 1111… (first eight bits locked in)
IPv6 - FF00::/8
What is Modified EUI-64 Addressing and where is it used?
Extended Universal Identifier 64-bit format (EUI-64) Uses the typical 48-bit MAC Address to automatically create a unique 64-bit IPv6 interface ID. The interface ID in IPv6 is the same as the host portion of an IPv4 address.
1. Insert fffe in the middle of the MAC. (ex: MAC Address - 00:90:27:17:FC:0F > 0090:27ff:fe17:fc0f)
2. The 7th bit in the first octet is inverted. (ex: 0090:27ff:fe17:fc0f > flip bit > 0290:27ff:fe17:fc0f)
This is used in link-local addresses. (ex: fe80::0290:27ff:fe17:fc0f/64)
What is an IPv6 address prefix?
ipv6-prefix/prefix-length, can be used to represent the same thing a network prefix does in IPv4 (ex: 10.1.1.0/24)
example: 2001:db8:8086:6502::/32
What are the different IPv6 address scopes?
Interface-Local
Link-Local
Site-Local
Organization-Local
Global
What are the 3 basic types of IPv6 addresses?
Unicast - use in a one-to-one context
Multicast - identifies a group of interfaces, traffic that is sent to a multicast address is sent to multiple destinations at the same time. An interface can belong to any number of multicast groups.
Anycast - address that is assigned to an interface on more than one node. When a packet is sent to an anycast address, it is routed to the nearest interface with that address according to the routing protocol used. All nodes with the address should behave in the same way, so it doesn’t matter which node services the request.
What is SLAAC?
Stateless Address Autoconfiguration, this method requires a 64-bit interface ID.
NOTE: IPv6 unicast addresses generally use 64 bits for the network ID and 64 bits for the interface ID. The network ID is administratively assigned and the interface ID can be configured manually or autoconfigured.
Which address bits define the unique Group ID in a Multicast IPv6 address?
The last 112 bits.
For both IPv4 and IPv6, how are (public/global) IP addresses assigned?
They are assigned in a hierarchical manner.
User/Business IP addresses
> ISP
> Local Internet Registry (LIR) or National Internet Registry (NIR) or Regional Internet Registry (RIR)
> Internet Corporation for Assigned Named and Numbers (ICANN) the operator for IANA.
What are the parts of a IPv6 Global Unicast Address?
001 (first three bits) + Global Routing Prefix (45 bits) + Subnet ID (16 bits) + Interface ID (64 bits)
NOTE: ISP’s generally hand out a /48 bit prefix, so a business/person would then have 16 network bits for subnetting.
(2^16 = 65,536 subnets available)
What are the well-known IPv6 Multicast addresses?
