Posted filed under Cisco CCNP.


 
Source Logical Operations

 
Get our complete tutorial in PDF
 

 

 

Configuring IPv6

  • Overview of IPv6
  • Implement IPv6 Addressing
  • Implement IPv6 and IPv4
  • Transition from IPv4 to IPv6

IPv6 Overview

  • Solves the problem of shrinking IP address pools
  • Solves many administrative inefficiencies cause by manual configuration

 

IPv6 Benefits

  • Extended address space
  • Hierarchical addressing and router efficiency
  • Stateless and stateful address auto-configuration
  • Eliminates broadcasts
  • Integrated security (IPSec)
  • Integrated QoS
  • Eliminates need for NAT

Comparing IPv4 and IPv6

Characteristic IPv4 IPv6
Addresses 32 bit 128 bit
IPSec support Optional Required
QoS Header does not include packet flow info for QoS Header includes flow label field for QoS
Checksum Included Not included
Packet fragmentation Both sending and receiving host fragment Sending host determines packet size
IGMP IGMP used to manage multicast membership Multicast Listener Discovery (MLD) determines multicast group membership
Router discovery Optional ICMPv6 Router Solicitation and Router Advertisement messages
Broadcasting Broadcast addresses used to send traffic to all hosts on a subnet Broadcasting replaced by multicasting
ARP Resolves IP address to MAC address Multicast neighbor solicitation
Configuration Manual or DHCP Auto-configuration
Resource records Host (A) IPv6 Host (AAAA)

 

IPv6 Address Space

  • IPv4 address bit order, expressed as decimal and binary:IPv6 address space
  • IPv6 uses 128-bit addresses – 4 times the length of IPv4.
  • Separated into eight 16-bit blocks:
    IPv6 address space2

IPv6 Address Space (Cont.)

IPv6 Address Space3

 

 

 

Converting from binary to hexadecimal for IPv6:

  • Take the first 16-bit block and break it into four groups of four bits as shown:
    0010 0000 0000 0001
  • Convert each bit in a group from right to left, with 0 converting to 0, and 1 converting to its position value:
    2001
  • Separate each converted block with a colon:
    2001:0DB8:0000:2F3B:02AA:00FF:FE28:9C5A

The Hexadecimal Numbering System

  • Base 16 numbering system
  • 0 through 9, A through F
    Binary Decimal Hexadecimal
    0001 1 1
    0010 2 2
    0011 3 3
    0100 4 4
    0101 5 5
    0110 6 6
    0111 7 7
    1000 8 8
    1001 9 9
    1010 10 A
    1011 11 B
    1100 12 C
    1101 13 D
    1110 14 E
    1111 15 F

 

Zero Compression

  • Allows reduction of notation
  • Adjacent zeros are compressed
  • One or more blocks of zeros can be written as ::
  • Only one set of :: in an address
  • Single block of zeros can also be written as 0

Example:

2001:0DB8:0000:0000:02AA:00FF:FE28:9C5A

After dropping lead 0s and using zero compression:

2001:DB8::2AA:FF:FE28:9C5A 

 

IPv6 Prefixes

  • Network part of address
  • Can be aggregated for route summarization
Category Prefix Hex Value Prefix Binary Value
Reserved 0000 0000
Global unicast address 2 or 3 001
Link-local unicast addresses FE8 1111 1110 1000
Unique local unicast addresses FD 1111 1100
Multicast addresses FF 1111 1111

 

Unicast Addresses

  • Global unicast address
    • Public, routable, from an ISP
  • Link-local unicast addresses
    • Automatically generated
    • Non-routable
    • Similar in function to IPv4 APIPA addresses
  • Unique local unicast addresses
    • Routable within an organization
    • Not routable on the Internet
    • Similar in function to IPv4 private addresses

Unique Local Unicast Addresses

Unique Local Unicast Addresses

Zone ID

  • Relative to sending host
  • Identifies the interface that is transmitting
  • Syntax is address%zone_ID

 

IPv6 Address Auto-configuration

  • Automatic for IPv6-enabled hosts
  • Stateless
    • Host auto-assigns link-local address
    • Checks to see if link-local address is a duplicate
    • Collects all valid prefixes advertised by adjacent routers
    • Creates a global IPv6 address within each advertised /64 IPv6 prefix
    • Uses either EUI-64 format or pseudo-random host ID as specified by RFC
  • Stateful
    • Obtained from DHCPv6
  • Combination of stateless and stateful

Node Types

  • IPv4 only
  • IPv6 only
  • IPv6/IPv4 – Uses both IPv4 and IPv6
  • IPv4 – Uses IPv4; can be configured for IPv6
  • IPv6 – Uses IPv6; can be configured for IPv4

IPv6 over IPv4

  • Used in Windows 2008 and Windows 2012
  • Also called “6over4”
  • A transition mechanism
  • Does translations from IPv4 to IPv6
  • Uses multicast; both nodes and routers

Dual-Layer Architecture

  • Microsoft has dual IP layer
  • Not dual IP stack
  • Both IPv4 and IPv6 share same information in same TCP/IP stack
  • Single shared implementation of TCP and UDP

 

DNS Requirements

  • Required for both IPv4
  • and IPv6
  • IPv4 Host record (A)
  • IPv6 Host record (AAAA)
  • PTR

Tunneling

  • ISATAP
  • The 6to4 protocol
  • Teredo

ISATAP

  • Transmits packets on top of IPv4
  • Treats IPv4 infrastructure as a non-broadcast multi-access network
  • IPv6 address auto-configuration
  • Queries DNS for address of ISATAP router
  • ISATAP router encapsulates IPv6 into IPv4 packets
  • Not “NAT friendly”

The 6to4 Protocol

  • Unicast connectivity between IPv6 across IPv4
  • IPv6 encapsulated in IPv4
  • Address format 2002:WWXX:YYZZ:Subnet_ID:Interface_ID
  • Not “NAT friendly”

Teredo

  • A NAT traversal technology
  • Full IPv6 connectivity to IPv6 hosts that are on an IPv4 network
  • Encapsulates IPv6 in IPv4 UDP messages
  • Clients are assigned an IPv6 address that starts with (2001:0::/32)
  • Teredo server initially configures Teredo tunnel
  • Teredo relay – remote end de-encapsulates Teredo tunnel

PortProxy

  • Transition mechanism
  • Application gateway
  • Proxies TCP traffic between IPv4 and IPv6 nodes
  • Connection can be forwarded using the same or another protocol to the specified port number
  • Allows you to run IPv4 only services (like terminal services) over IPv6
  • The following nodes can access each other:
    • An IPv4-only node can access an IPv4 node.
    • An IPv4 node can access an IPv6 node.
    • An IPv6 node can access an IPv6 node.
    • An IPv6 node can access an IPv4 node.

Migration Considerations

  • Application support
  • Current routing infrastructure
  • DNS infrastructure needs
  • Supporting nodes
  • Preparation and baselines
  • Monitoring steps

 

Want more information on how to become Cisco CCNP Certified? Learn more!

 


Also published on Medium.

Comments are closed.