IP v6 Address basicsIP v6 Address basicsV.SHAJI V.SHAJI

SDE ( Computer & e-Campus ) SDE ( Computer & e-Campus ) RTTC/Trivandrum.9446450450RTTC/Trivandrum.9446450450

IPv6 Address Syntax

For IPv6, the 128-bit address is used and is divided along 16-bit boundaries.

Each 16-bit block is converted to a 4-digit hexadecimal number and separated by colons.

The resulting representation is called colon hexadecimal.

The following is an IPv6 address in binary form: 0010000000000001000011011011100000000000000

0000000101111001110110000001010101010000000001111111111111110001010001001110001011010

The 128-bit address is divided along 16-bit boundaries:

0010000000000001 0000110110111000 0000000000000000 0010111100111011

0000001010101010 0000000011111111 1111111000101000 1001110001011010

Each 16-bit block is converted to hexadecimal and delimited with colons. The result is the following:

2001:0db8:0000:2f3b:02aa:00ff:ff28:9c5a

IPv6 Address Notation

Any leading zeros in a group may be omitted; thus, the given example becomes

2001:db8:85a3:0:0:8a2e:370:7334

(2001:0db8:85a3:0000:0000:8a2e:0370:7334 )

IPv6 Address Notation

One or any number of consecutive groups of 0 value may be replaced with two colons (::)

2001:db8:85a3::8a2e:370:7334

(2001:db8:85a3:0:0:8a2e:370:7334)

This substitution with double-colon may be performed only once in an address, because multiple occurrences would lead to ambiguity.

IPv6 Address Notation

The illegal address notation 2001::FFD3::57ab, could represent

2001:0:0:0:0:FFD3:0:57ab 2001:0:0:0:FFD3:0:0:57ab 2001:0:0:FFD3:0:0:0:57ab & 2001:0:FFD3:0:0:0:0:57ab

IPv6 Address Notation

The addresses below are all valid and equivalent

2001:0db8:0000:0000:0000:0000:1428:57ab 2001:0db8:0000:0000:0000::1428:57ab 2001:0db8:0:0:0:0:1428:57ab 2001:0db8:0:0::1428:57ab 2001:0db8::1428:57ab 2001:db8::1428:57ab

IPv6 Address Notation

Networks are written in CIDR notation: a network is denoted by the first address in the network and the size in bits of the prefix, separated by a slash "/".

For example, the network written 2001:0db8:1234::/48

starts at address 2001:0db8:1234:0000:0000:0000:0000:0000

and ends at 2001:0db8:1234:ffff:ffff:ffff:ffff:ffff

IPv6 Address parts

IPv6 addresses are typically composed of two logical parts:

64-bit network prefix, and

64-bit host part, which is either automatically generated from the interface's MAC address or assigned sequentially.

IPV6 Address = network prefix + host part

Types of IPv6 Addresses

1. Unicast: A unicast address identifies a single interface within the scope of the type of address. The scope of an address is the region of the IPv6 network over which the address is unique. With the appropriate unicast routing topology, packets addressed to a unicast address are delivered to a single interface.

2. Multicast

A multicast address identifies zero or more interfaces on the same or different hosts. With the appropriate multicast routing topology, packets addressed to a multicast address are delivered to all interfaces identified by the address.

3. Anycast

An anycast address identifies multiple interfaces. With the appropriate unicast routing topology, packets addressed to an anycast address are delivered to a single interface—may be the nearest interface that is identified by the address.

IPv6 Address types: Unicast

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HTTP

HTTP

NTP

NTP

Host

The Network Time Protocol (NTP) is a protocol for synchronizing the clocks of computer systems over packet-switched data networks.

IPv6 Address types: Anycast

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3 Hops away

4 Hops away

HTTP

HTTP

NTP

NTP

Host

Example:NTP Servers use the same anycast addresses.Anycast takes shortest link to NTP server.

Host

IPv6 Address types: Multicast

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Video

Video

NTP

NTP

HostHost

IPv6 Unicast Addresses

IPv6 unicast addresses are:

1. Global unicast addresses

2. Link-local addresses

3. Site-local addresses

4. Unique local addresses

5. Special addresses

6. Transition addresses

1.Global Unicast Addresses

IPv6 global addresses are equivalent to public IPv4 addresses. They are globally routable and reachable on the IPv6 Internet.

The fields in the global unicast address

Fixed portion set to 001: The three high-order bits are set to 001. Global Routing Prefix : Indicates the global routing prefix for a

specific organization’s site. The combination of the three fixed bits and the 45-bit Global Routing Prefix is used to create a 48-bit site prefix, which is assigned to an individual site of an organization.

Subnet ID : The Subnet ID is used within an organization’s site to identify subnets within its site. The size of this field is 16 bits.

Interface ID : Indicates the interface on a specific subnet within the site. The size of this field is 64 bits.

An example 2001:DB8:4D1C:221A::/64

2.Link-Local Addresses

IPv6 link-local addresses, identified by the initial 10 bits being set to 1111 1110 10 and the next 54 bits set to 0, are used by nodes when communicating with neighbouring nodes on the same link.

IPv6 link-local addresses are similar to IPv4 link-local addresses 169.254.0.0/16 (APIPA) in Windows

2.Link-Local Addresses

Link-local addresses always begin with FE80 with the 64-bit interface identifier.

(FE80 = 1111 1110 10...) The prefix for link-local addresses is always FE80::/64. An IPv6 router never forwards link-local traffic beyond the

link.

3. Site-Local Addresses

Site-local addresses, identified by setting the first 10 bits to 1111 1110 11, are equivalent to the IPv4 private address space (10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16).

3. Site-Local Addresses

Unlike link-local addresses, site-local addresses are not automatically configured and must be assigned either through stateless or stateful address autoconfiguration.

The first 10 bits are always fixed for site-local addresses,

beginning with FEC0::/10 (1111 1110 11). After the 10 fixed bits is a 54-bit Subnet ID field that provides 54 bits with which you can create subnets within your organization.Unlike link local , this can be used for different subnets of a company. That is why /10 is fixed instead of /64

3. Site-Local Addresses

Site-local addresses are not reachable from other sites, and routers must not forward * site-local traffic outside the site. Site-local addresses can be used in addition to global addresses.

Site-local addresses have been formally deprecated.

4. Unique Local Addresses

Site-local addresses provide a private addressing alternative to global addresses for intranet traffic. However, because the site-local address prefix can be reused to address multiple sites within an organization, a site-local address prefix can be duplicated.

To replace site-local addresses with a new type of address is introduced called ULA , that is private to an organization yet unique across all the sites of the organization

The first 7 bits have the fixed binary value of 1111 110

4. Unique Local Addresses

All ULA have the address prefix FC00::/7 (1111 110). The Local (L) flag(8th bit) is set 1 to indicate that the prefix is locally assigned. The L flag value set to 0 is not defined in RFC 3879.

Therefore, ULA within an organization with the L flag set to 1 have

the address prefix of FD00::/8. (1111 111).

5.Special IPv6 Addresses

1. Unspecified address The unspecified address (0:0:0:0:0:0:0:0 or ::) is used

only to indicate the absence of an address. It is equivalent to the IPv4 unspecified address of

0.0.0.0. The unspecified address is typically used as a source

address when a unique address has not yet been determined.

The unspecified address is never assigned to an interface or used as a destination address.

5.Special IPv6 Addresses

2. Loopback address

The loopback address (0:0:0:0:0:0:0:1 or ::1) is assigned to a loopback interface, enabling a node to send packets to itself.

It is equivalent to the IPv4 loopback address of 127.0.0.1.

6. Transition Addresses

To aid in the transition from IPv4 to IPv6 and the coexistence of both types of hosts, the following addresses are defined:

IPv4-compatible addressIPv4-mapped address6to4 addressISATAP addressTeredo address

ISATAP/Teredo

ISATAP (Intra-Site Automatic Tunnel Addressing Protocol) adapter encapsulates IPv6 packets by using an IPv4 header.

This functionality enables the client to transport IPv6 traffic over an IPv4 infrastructure.

Teredo, also known as IPv4 NAT traversal for IPv6 , provides unicast IPv6 connectivity across the IPv4 Internet.

Teredo provides address assignment and host-to-host automatic tunneling for unicast IPv6 connectivity across the IPv4 Internet when IPv6/IPv4 hosts are located behind one or multiple IPv4 NATs.

NAT also involved in Teredo. NAT not involved in ISATAP

.

(IANA)Internet Assigned Numbers Authority

Regional Internet Registries (RIR)world map

AFRINIC (African Network Information Center) (APNIC) Asia Pacific Network Information Centre (ARIN) American Registry for Internet Numbers (LACNIC) Latin America and Caribbean Network Information Centre

(RIPE NCC) Réseaux IP Européens Network Coordination Centre

Hierarchical Addressing and Aggregation

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IPv6 Address Representation EUI 64

One of IPv6's key benefits over IPv4 is its capability for automatic interface addressing.

By implementing the IEEE's 64-bit Extended Unique Identifier (EUI-64) format, a host can automatically assign itself a unique 64-bit IPv6 interface identifier without the need for manual configuration or DHCP.

This is done in two steps. The first step is by converting the 48-bit MAC address to a 64-bit

value by adding the middle 16 bits “FF FE” in between Manufacture ID and serial number of the MAC address.

IPv6 Address Representation EUI 64

The second step is to invert the universal/local (U/L) flag (bit 7) in the OUI portion of the address.

Globally unique addresses assigned by the IEEE originally have this bit set to zero, indicating global uniqueness.

Likewise, the U/L bit is inverted when using an EUI-64 address as an IPv6 interface ID , indicating local uniqueness.

Multicast Addresses

IPv6 multicast addresses have the Format Prefix of 1111 1111.

An IPv6 address is simple to classify as multicast because it always begins with FF.

Multicast addresses cannot be used as source addresses. Multicast addresses include additional structure to

identify their flags, scope, and multicast group

Multicast Addresses

Flags If 0, the multicast address is a permanently assigned, well-known multicast address allocated by the Internet Assigned Numbers Authority (IANA). If 1, the multicast address is a not permanently assigned, or transient.

Scope :Indicates the scope of the IPv6 internetwork for which the multicast traffic is intendedScope Field Value Scope

0 Reserved

1 Node-Local

2 Link-Local

5 Site-Local

8 Organization Local

E Global

F Reserved

The Group ID field identifies the multicast group and is unique within the scope:

Multicast Addresses

well-known IPv6 multicast addresses.

Address Multicast Group

FF02::1 All Nodes

FF02::2 All Routers

FF02::5 OSPFv3 Routers

FF02::6 OSPFv3 Designated Routers

FF02::9 RIPng Routers

FF02::A EIGRP Routers

FF02::B Mobile Agents

FF02::C DHCP Servers/Relay Agents

FF02::D All PIM Routers

Anycast addresses can be considered a conceptual cross between unicast and multicast addressing. Where unicast says “send to this one address” and multicast says “send to every member of this group”, anycast says “send to any one member of

this group”. There is no special anycast addressing scheme. anycast addresses are the same as unicast addresses. An anycast address is created “automatically” when a unicast address is assigned to more than one interface.

Anycast Addresses

Practicals

Assign an IP ( 2002:abcd::1234/64 or/32) Show the /64 autocoming Ping locally Ping from comp to comp If mask is changed , they cant communicate In IPV6 there is no N/w address and broadcast address ,demonstrate by

giving the address say 2001::/64 (first address in the network) and 2001::ffff:ffff:ffff:ffff /64 is also taken.

2001::/64( n/w address ) and 2001::ffff:ffff:ffff:ffff /64 (broadcast address) assign to PC and do ping . Also demo for an IPV4 we cant assign n/w address and b/c address

Connect RDC via IPV6 from one pc to another.