Download Transitioning to IPv6

Transitioning to IPv6
April 15,2005
Presented By:
Richard Moore
PBS Enterprise Technology
Agenda
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Benefits of IPv6
What is IPv6?
IPv6 Operation
IPv6 Deployment
IPv6 Challenges
Resources
Improved Routing Efficiency
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IPv6’s large addressing space
Multi-level address hierarchy
Reduces the size of Internet routing tables
All fields in the IPv6 header are 64 bit aligned
Interface ID
Network Prefix
xxxx
xxxx
xxxx
xxxx
xxxx
128 bits
XXXX = 0000 through FFFF
xxxx
xxxx
xxxx
Supports Autoconfiguration
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Accommodates mobile services
Accommodates Internet capable appliances
Decreases complexity of network discovery
Simplifies renumbering of existing networks
Simplifies transition between networks
Embedded IPsec
> IPsec is a mandatory part of IPv6 protocol
> Protocol provides security extension headers
> Eases implementation of encryption, authentication,
and VPN
> Provides end-to-end security
Support for Mobile IP and Mobile
Computing Devices
> Allows mobile devices to move without breaking
existing connections
> Care-of-Address eliminates need for foreign agents
> Simplifies communication of Corresponding nodes
directly with Mobile nodes
Elimination of Network Address
Translation (NAT)
> NAT is a mechanism to share or reuse the same address
space among different network segments
> NAT places a burden on network devices and
applications to deal with address translation
Supports Widely Deployed Routing
Protocols
> Extended support for existing Interior Gateway
Protocols and Exterior Gateway Protocols
> For example:
OSPFv3, IS-ISv6, RIPng, MBGPv4+
Improved Support for Multicast
> Replaces IPv4 broadcast functionality
> Improves network efficiency
IPv6 Header Format
IPv4 Header
Version
IHL
Type of
Service
Identification
Time to
Live
Protocol
IPv6 Header
Total Length
Flags
Fragment
Offset
Header
Checksum
Source Address
Destination Address
Options
Padding
Version
Traffic
Class
Payload Length
Flow Label
Next
Header
Source Address
Destination Address
> IPv6 header is streamlined for efficiency
> Greater flexibility to support optional features
Hop
Limit
IPv6 Extension Headers
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Extension header is optional
64 bit aligned, lower overhead
No size limit as with IPv4
Processing only by destination node.
Next header field identifies the extension header
IPv6 Addressing
> 128-bit address is separated into eight 16-bit
hexadecimal numbers
> For example:
2013:0000:1F1F:0000:0000:0100:11A0:ADFF
IPv6 Addressing
> Conventions are used to represent IPv6 addresses
> Leading zeros can be removed, 0000 = 0 (compressed
form)
> “::” represents one or + groups of 16 bits zeros
> For example:
2001:0:13FF:09FF:0:0:0:0001 = 2001:0:13FF:09FF::1
IPv6 Addressing
> Lower four 8 bits can use decimal representation of
IPv4 addresses
> For example:
0:0:0:0:0:0:192.168.0.1
> IPv6 node allows more than one type of IP address
Unicast & Global Unicast Addressing
> Unicast: An address used to identify a single interface
> Global Unicast: An address that can be reached and
identified globally
128 bits
Provider
3 bits
Site
Host
45 bits
16 bits
64 bits
Global Routing Prefix
Subnet ID
Interface ID
001
Global Unicast Address Format
Site-local Unicast Addressing
> An address that can only be reached and identified
within a customer site
> Similar to IPv4 private address
128 bits
64 bits
0
1111111011
FEC0::/10
Interface ID
Subnet ID
16 bits
10 bits
Site-local Unicast Address Format
Link-local Unicast Addressing
> An address that can only be reached and identified by
nodes attached to the same local link.
128 bits
64 bits
0
Interface ID
1111111010
FE80::/10
10 bits
Link-local Unicast Address Format
Anycast Addressing
> A global address that is assigned to a set of interfaces
belonging to different nodes
> Must not be used as source address of IPv6 packet
> Must not be assigned to an IPv6 host
128 bits
N bits
Subnet ID
128 – N bits
00000000000000000000
Anycast Address Format
Multicast Addressing
> Address assigned to a set of interfaces belonging to
different nodes
128 bits
112 bits
Group ID
1111 1111
F
F
8 bits
Flag
Flag
Scope
8 bits
Multicast Address Format
Scope
0 if permanent
1 if temporary
1 = interface – local
2 = link – local
3 = subnet – local
4 = admin – local
5 = site – local
8 = organization – local
E = global
Neighbor Discovery
> Determines link-layer address of neighbor on the same
network
> Determines the link-layer address of another node on
the same local link
> Advertisement messages are also sent when there are
changes in link-layer addressing of a node on a local
link
Router Discovery
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Discovers routers on local link using advertisements
and solicitation messages
Determines type of autoconfiguration a node should
use
Determines Hop limit value
Determines network prefix
Determines lifetime information
Determines default router
Stateless Autoconfiguration and
Renumbering of IPv6 Nodes
> Stateless autoconfiguration uses network prefix
information in router advertisement messages
> Remaining 64 bits address is obtained by the MAC
address assigned to the Ethernet interface combined
with additional bits in EUI-64 format
> Renumbering of IPv6 nodes is possible through router
advertisement messages containing old and new prefix
Path Maximum Transfer Unit (MTU)
> IPv6 routers do not handle fragmentation of packets
> Uses ICMP error reports to determine packet size
matching MTU size
> Allows a node to dynamically discover and adjust
differences in MTU size
DHCPv6 and DNS
> Supports stateful configuration with DHCPv6
> Node has option to solicit an address via DHCP server
when a router is not found
> DHCPv6 is similar to DHCPv4
> DHCPv6 uses multicast for messaging
> New record type to accommodate IPv6 addressing in
DNS
Dual-stack Backbone
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All routers maintain both IPv4 and IPv6 protocol stacks
Applications choose between using IPv4 or IPv6
All routers in the network must be upgraded to IPv6
All routers must have sufficient memory for both IPv4
and IPv6 routing tables
IPv6 over IPv4 Tunneling
> Encapsulates IPv6 traffic within IPv4 packets
Original Packet
IPv6
Source of
original packet
Tunnel
Entry Node
Tunnel Packet
IPv6
IPv4/IPv6
Dual stack
Destination of
original packet
IPv6 over IPv4
Tunnel
IPv4/IPv6
Dual stack
IPv6 over IPv4 Tunneling
Tunnel
Exit Node
Original Packet
Tunnel Packet
IPv6
Transport
Header
Header
IPv6
IPv4
Header Header
Transport
Header
IPv6
Payload
IPv6
Payload
Manually Configured Tunnels
> Defined by RFC 2893, both end points of tunnel must be
configured with appropriate IPv6 and IPv4 addresses
> Edge routers will forward tunneled traffic based on the
configuration
GRE Tunnels
> GRE allows one network protocol to be transmitted
over another network protocol
> Packets are encapsulated to be transmitted within GRE
packets
> GRE is an ideal mechanism to tunnel IPv6 traffic
IPv4 Compatible Tunnels
> Defined in RFC 2893, tunnel mechanisms automatically
set up tunnels based on IPv4-compatible IPv6 addresses
> IPv4-compatible IPv6 address defines the left-most 96
bits as zero, followed by an IPv4 address
> For example:
0:0:0:0:0:0:64.29.51.26
6to4 Tunnels
> Defined by RFC 3056, 6to4 tunneling uses an IPv4
address embedded in the IPv6 address
> Identifies the end point and configures tunnel
automatically
16 bits
32 bits
16 bits
64 bits
2002
IPv4 Address
Subnet
Interface ID
6to4 Tunneling Address Format
ISATAP Tunnels
> ISATAP tunneling is similar to 6to4 tunneling
> Designed for use in a local site or campus network
64 bits
32 bits
32 bits
Subnet Prefix
00005EFE
IPv4 Address
ISATAP Tunneling Address Format
Teredo Tunnels
> 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.
> To traverse IPv4 NATs, IPv6 packets are sent as IPv4based User Datagram Protocol (UDP) messages.
32 bits
32 bits
16 bits
Teredo Prefix
Teredo Server
IPv4 Address
Flags
16 bits
32 bits
Obscured
Obscured
External Port External Address
Teredo Tunneling Address Format
MPLS Tunnels
> Isolated IPv6 domains can communicate with each
other over MPLS IPv4 core networks
> MPLS forwarding is based on labels rather than IP
headers requiring fewer infrastructure upgrades or
reconfigurations
> Allows IPv6 networks to be combined into VPNs or
extranets over IPv4 VPN infrastructure
IPv6 Challenges
IPv6 Transition
1996 - 2001
2002
2003
2004
2005
2006
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
2007 - 2010
Early Adopters
Application Port <= Duration 3+ Years =>
ISP Adoption <= Duration 3+ Years =>
Consumer Adoption <= Duration 5+ Years =>
Enterprise Adoption <= Duration 5+ Years =>
Early Adopters:
Europe, Japan, China, North
America IPv6 Task Force
Resources
> Questions or Comments?
[email protected]