Transcript IPv6 Introduction: Network and Applications

Introduction to IPv6
Network & Application
Passakon Prathombutr
Next Generation Internet (NGI)
National Electronics and Computer Technology Center
Needs for IPv6
•
•
•
•
Unlike Y2K
IPv4-1970, IPv6-1990
Exhaustion of IP (v4) addresses
Why not IPv5?
– “5” becomes stream protocol, ST, assigned in
version field of header.
• Enhance features
2/19
Technological Imperatives for
Adoption
• Need Killer Application?
• Network Address Translation (NAT)
– Not for IPSec, QoS, VoIP, Peer-to-Peer
• Dynamic Host Configuration
Protocol (DHCP)
• Classless Inter-Domain Routing
(CIDR)
3/19
What is IPv6?
• Internet Protocol Version 6 designed by
IETF to replace current IP (IPv4)
• More address spaces (128-bits)
• New header design and features
4/19
Header comparison
15 16
0
vers
hlen
TOS
identification
20
bytes
TTL
31
flags
protocol
Removed (6)
total length
• ID, flags, flag offset
• TOS, hlen
• header checksum
flag-offset
header checksum
source address
destination address
Changed (3)
options and padding
• total length => payload
• protocol => next header
• TTL => hop limit
IPv4
vers
traffic class
payload length
40
bytes
flow-label
next header
Added (2)
hop limit
source address
• traffic class
• flow label
Expanded
destination address
• address 32 to 128 bits
IPv6
5/19
IPv6 Changes
IPv4
Source and destination
addresses
IPsec support
32 bits (4 bytes)
Optional
Identification of packet flow for
QoS handling by routers
None in header
Fragmentation
By both routers
and sending host
Header checksum
Included
Header optional data
Included
6/19
IPv6
128 bits (16 bytes)
Standard
Included in header
Only by sending
host
Not included
Moved to
extension headers
IPv6 Changes
IPv4
IP address resolution method
Managing local subnet group
membership
Determine best default gateway
Sending traffic to all nodes on
subnet
Broadcast ARP
request frames
IGMP
IPv6
Multicast Nghbrhd.
Solicitation
messages
Multicast Listener
Discovery (MLD)
ICMP Router
Discovery (opt.)
ICMPv6 Router
Solicitation & Adv.
messages (req.)
Broadcast
addresses
Multicast address
7/19
IPv6 Changes
IPv4
Configuration
Host address resource records
used to map to IP addresses
Pointer resource records in DNS
domain used to map to host
Packet size support
IPv6
Manually or
through DHCP
Automatic
A
AAAA or A6
IN-ADDR.ARPA
IP6.INT
576-byte (possibly
fragmented)
1280 byte (no
fragmentation)
8/19
What it Means
• Simplified header
– Faster router processing
– Less overhead
• Efficient option processing
• No fragmentation
– Reduced load on routers
– Easier to implement in hardware
– Easy Layer 3 switching of IP
• Minimum link MTU is 1280 bytes
9/19
IPv6 Address Structure
• Interface ID
– Unique identifier for each host (48-bit
MAC address + some padding)
– Structure of a ‘Provider Based
Unicast’ (like IPv4 with CIDR)
– No more ‘classes’ (A,B,C,D,E)
– More ‘granularity’ than IPv4 or IPv4
CIDR
– No need to specify subnet mask
10/19
Major Improvement of
IPv6 Header
• No Option field. Replaced by extension
header. Result in a fixed length, 40byte IP header.
• No header checksum. Result in fast
processing.
• No fragmentation at intermediate nodes.
Result in fast IP forwarding.
11/19
128-bit IPv6 Address
3FFE:085B:1F1F:0000:0000:0000:00A9:1234
8 groups of 16-bit hexadecimal numbers
separated by “:”
Leading zeros can be removed
3FFE:85B:1F1F::A9:1234
:: = all zeros in one or more group of 16-bit
hexadecimal numbers
12/19
Prefix Allocation
Type
Global (+anycast)
Link-local
Site-local
Multicast
Prefix (binary bits)
001
1111 1110 10
1111 1110 11
1111 1111
Range
2xxx to 3xxx
FE8x to FEBx
FECx to FEFx
FFxx
Link-local: Unreachable from other sites, equivalent to IPv4 private addr.
Site-local: Used to communicate with neighbor node on the same link.
Global Allocation:
2001::/16
Sub-TLA Assignment (by APNIC, ARIN, RIPE)
2002::/16
6to4 (simply generated from 1 public IPv4 address)
3FFE::/16
6bone (e.g., NECTEC got 3FFE:4016::/32)
13/19
Benefits of IPv6
• Improve efficiency in routing and packet
handling
– Large addressing space and network prefixes –
short and scalable routing table
– Header format is simpler than that of the IPv4
header – good for 64-bit processors
• Support Plug and Play address autoconfiguration/ renumbering
– Good for mobile IP wireless devices, and
home appliances.
– Easier to transit from one provider to
another.
14/19
Benefits of IPv6 (cont.)
• Support for embedded IPSec
– Encapsulating Security Payload (ESP) and Authentication Header (AH)
are parts of extension headers
• Improve support for multicast – No more
broadcast addresses
• Eliminate the need for NAT
• Support for widely deployed routing
protocols e.g., OSPFv3, IS-ISv6, RIPng and
BGP4+
15/19
Techniques for Transition
• Dual stack
• Between IPv6 islands via IPv4 cloud
– IPv6-over-4 configured tunnel, 6to4,
6over4, ISATAP, Tunnel broker (freenet6,
Hurricane Electric, TILAB)
• Between IPv6 and IPv4
– DSTM(Dual-Stack Transition Mechanism),
NAT-PT(Network Address TranslationProtocol Translation), SIIT (Stateless IPv6IPv4 Translator), BIS(Bump-In-the-Stack),
BIA(Bump-In-the-API), TCP-UDP relay
16/19
6to4 Tunneling
IPv4 202.57.124.186
IPv6 2002:CA39:7CBA::1/128
IPv4 192.150.240.24
IPv6 2002:C096:F018::1/128
2002:C096:F018::2/128
Tunnel
2002:CA39:7CBA::2/128
6to4
router
IPv4
Network
6to4 network
IPv6 packet
Src. 2002:CA39:7CBA::2/128
Dest. 2002:C096:F018::2/128
IPv4 packet
Src. 202.57.124.186
Dest. 192.150.240.24
IPv6 packet
Src. 2002:CA39:7CBA::2/128
Dest. 2002:C096:F018::2/128
17/19
6to4
router
6to4 network