Curs_IPv6.ppt

Outline
 Protocol Background
 Technology Highlights
 Enhanced Capabilities
 Transition Issues
 Next Steps

Why a New IP?
 1991 – ALE WG studied projections about
address consumption rate showed exhaustion
by 2008.
 Bake-off in mid-1994 selected approach of a
new protocol over multiple layers of
encapsulation.

What Ever Happened to IPv5?
0 IP March 1977 version
(deprecated)
1 IP January 1978 version (deprecated)
2 IP February 1978 version A (deprecated)
3 IP February 1978 version B (deprecated)
4 IPv4 September 1981 version (current widespread)
5 ST Stream Transport (not a new IP, little
use)
6 IPv6 December 1998 version (formerly SIP, SIPP)
7 CATNIP IPng evaluation (formerly TP/IX; deprecated)
8 Pip IPng evaluation (deprecated)
9 TUBA IPng evaluation (deprecated)
10-15 unassigned

What about technologies & efforts
to slow the consumption rate?
 Dial-access / PPP / DHCP
 Provides temporary allocation aligned with actual endpoint use.
 Strict allocation policies
 Reduced allocation rates by policy of ‘current-need’ vs. previous
policy based on ‘projected-maximum-size’.
 CIDR
 Aligns routing table size with needs-based address allocation policy.
Additional enforced aggregation actually lowered routing table
growth rate to linear for a few years.
 NAT
 Hides many nodes behind limited set of public addresses.

What did intense conservation efforts
of the last 5 years buy us?
 Actual allocation history
 1981 – IPv4 protocol published
 1985 ~ 1/16 total space
 The lifetime-extending efforts & technologies
delivered the ability to absorb the dramatic
growth in consumer demand during the late
90’s.
In short they bought – TIME –

Would increased use of
NATs be adequate?
 NO!
 NAT enforces a ‘client-server’ application model where the server has
topological constraints.
 They won’t work for peer-to-peer or devices that are “called” by
others (e.g., IP phones)
 They inhibit deployment of new applications and services, because all
NATs in the path have to be upgraded BEFORE the application can be
deployed.
 NAT compromises the performance, robustness, and security of the
Internet.
 NAT increases complexity and reduces manageability of the local
network.
 Public address consumption is still rising even with current NAT
deployments.

What were the goals of a
new IP design?
 Expectation of a resurgence of “always-on”
technologies
 xDSL, cable, Ethernet-to-the-home, Cell-phones, etc.
 Expectation of new users with multiple devices.
 China, India, etc. as new growth
 Consumer appliances as network devices
 (1015 endpoints)
 Expectation of millions of new networks.
 Expanded competition and structured delegation.
 (1012 sites)

Return to an End-to-End
Architecture
Global
Addressing
Realm
Always-on Devices
Need an Address
When You Call Them
New Technologies/Applications for Home Users
‘Always-on’—Cable, DSL, Ethernet@home, Wireless,…

Why is a larger address space
needed?
 Overall Internet is still growing its user base
 ~320 million users in 2000 : ~550 million users by 2005
 Users expanding their connected device count
 405 million mobile phones in 2000, over 1 billion by 2005
 UMTS Release 5 is Internet Mobility, ~ 300M new Internet connected
 ~1 Billion cars in 2010
 15% likely to use GPS and locality based Yellow Page services
 Billions of new Internet appliances for Home users
 Always-On ; Consumer simplicity required
 Emerging population/geopolitical & economic drivers
 MIT, Xerox, & Apple each have more address space than all of China
 Moving to an e-Economy requires Global Internet accessibility

Why Was 128 Bits Chosen
as the IPv6 Address Size?
Proposals for fixed-length, 64-bit addresses
 Accommodates 1012 sites, 1015 nodes, at .0001 allocation efficiency (3
orders of mag. more than IPng requirement)
 Minimizes growth of per-packet header overhead
 Efficient for software processing on current CPU hardware
Proposals for variable-length, up to 160 bits
 Compatible with deployed OSI NSAP addressing plans
 Accommodates auto-configuration using IEEE 802 addresses
 Sufficient structure for projected number of service providers
Settled on fixed-length, 128-bit addresses
 (340,282,366,920,938,463,463,374,607,431,768,211,456 in all!)

Benefits of
128 bit Addresses
 Room for many levels of structured hierarchy
and routing aggregation
 Easy address auto-configuration
 Easier address management and delegation
than IPv4
 Ability to deploy end-to-end IPsec
(NATs removed as unnecessary)

Incidental Benefits of
New Deployment
 Chance to eliminate some complexity in IP
header
 improve per-hop processing
 Chance to upgrade functionality
 multicast, QoS, mobility
 Chance to include new features
 binding updates

Summary of Main IPv6 Benefits
 Expanded addressing capabilities
 Structured hierarchy to manage routing table growth
 Serverless autoconfiguration and reconfiguration
 Streamlined header format and flow identification
 Improved support for options / extensions

IPv6 Advanced Features
 Source address selection
 Mobility - More efficient and robust mechanisms
 Security - Built-in, strong IP-layer encryption and
authentication
 Quality of Service
 Privacy Extensions for Stateless Address
Autoconfiguration (RFC 3041)

IPv6 Markets
 Home Networking
 Set-top box/Cable/xDSL/Ether@Home
 Residential Voice over IP gateway
 Gaming (10B$ market)
 Sony, Sega, Nintendo, Microsoft
 Mobile devices
 Consumer PC
 Consumer Devices
 Sony (Mar/01 - …energetically introducing IPv6 technology into hardware products …)
 Enterprise PC
 Service Providers
 Regional ISP, Carriers, Mobile ISP, and Greenfield ISP’s

IPv6 Markets
 Academic NRN:
 Internet-II (Abilene, vBNS+), Canarie*3, Renater-II, Surfnet, DFN,
CERNET,… 6REN/6TAP
 Geographies & Politics:
 Prime Minister of Japan called for IPv6 (taxes reduction)
 EEC summit PR advertised IPv6 as the way to go for Europe
 China Vice minister of MII deploying IPv6 with the intent to take a
leadership position and create a market force
 Wireless (PDA, Mobile, Car,...):
 Multiple phases before deployment
 RFP -> Integration -> trial -> commercial
 Requires ‘client devices’, eg. IPv6 handset ?

0 31
Version Class Flow Label
Payload Length Next Header Hop Limit
128 bit Source Address
128 bit Destination Address
4 12 24
16
The IPv6 Header
40 Octets, 8 fields

0 31
Ver IHL Total Length
Identifier Flags Fragment Offset
32 bit Source Address
32 bit Destination Address
4 8 24
16
Service Type
Options and Padding
Time to Live Header Checksum
Protocol
The IPv4 Header
20 octets + options : 13 fields, including 3 flag bits
shaded fields are absent from IPv6 header

Summary of Header Changes
between IPv4 & IPv6
 Streamlined
 Fragmentation fields moved out of base header
 IP options moved out of base header
 Header Checksum eliminated
 Header Length field eliminated
 Length field excludes IPv6 header
 Alignment changed from 32 to 64 bits
 Revised
 Time to Live  Hop Limit
 Protocol  Next Header
 Precedence & TOS  Traffic Class
 Addresses increased 32 bits  128 bits
 Extended
 Flow Label field added

Extension Headers
next header =
TCP
TCP header + data
IPv6 header
next header =
Routing
TCP header + data
Routing header
next header =
TCP
IPv6 header
next header =
Routing
fragment of TCP
header + data
Routing header
next header =
Fragment
Fragment header
next header =
TCP
IPv6 header

Extension Headers (cont.)
 Generally processed only by node identified in
IPv6 Destination Address field => much lower
overhead than IPv4 options processing
 exception: Hop-by-Hop Options header
 Eliminated IPv4’s 40-byte limit on options
 in IPv6, limit is total packet size,
or Path MTU in some cases
 Currently defined extension headers:
 Hop-by-Hop Options, Routing, Fragment,
Authentication, Encryption, Destination Options

Fragment Header
 though discouraged, can use IPv6 Fragment
header to support upper layers that do not (yet)
do path MTU discovery
 IPv6 frag. & reasm. is an end-to-end function;
routers do not fragment packets en-route if too
big—they send ICMP “packet too big” instead
Next Header
Original Packet Identifier
Reserved Fragment Offset 0 0 M

Routing
 Same “longest-prefix match” routing as IPv4
CIDR
 Straightforward changes to existing IPv4 routing
protocols to handle bigger addresses
 unicast: OSPF, RIP-II, IS-IS, BGP4+, …
 multicast: MOSPF, PIM, …
 Use of Routing header with anycast addresses
allows routing packets through particular regions
 e.g., for provider selection, policy, performance, etc.

Routing Header
Address[1]
Reserved
Address[0]
Next Header Hdr Ext Len Routing Type Segments Left
•
•
•

S A
B
D
Example of Using the Routing
Header

Some Terminology
node a protocol module that implements IPv6
router a node that forwards IPv6 packets not explicitly
addressed to itself
host any node that is not a router
link a communication facility or medium over which
nodes can communicate at the link layer,
i.e., the layer immediately below IPv6
neighbors nodes attached to the same link
interface a node’s attachment to a link
address an IPv6-layer identifier for an interface or a set
of interfaces

Text Representation of Addresses
“Preferred” form: 1080:0:FF:0:8:800:200C:417A
Compressed form: FF01:0:0:0:0:0:0:43
becomes FF01::43
IPv4-compatible: 0:0:0:0:0:0:13.1.68.3
or ::13.1.68.3

IPv6 - Addressing Model
Link-Local
Site-Local
Global
 Addresses are assigned to interfaces
No change from IPv4 Model
 Interface ‘expected’ to have multiple addresses
 Addresses have scope
Link Local
Site Local
Global
 Addresses have lifetime
Valid and Preferred lifetime

Types of IPv6 Addresses
 Unicast
 Address of a single interface
 Delivery to single interface
 Multicast
 Address of a set of interfaces
 Delivery to all interfaces in the set
 Anycast
 Address of a set of interfaces
 Delivery to a single interface in the set
 No more broadcast addresses

Interface Address set
 Loopback
 (only assigned to a single virtual interface per node)
 Link local
 Site local
 Auto-configured 6to4
 (if IPv4 public is address available)
 Auto-configured IPv4 compatible
 (operationally discouraged)
 Solicited node Multicast
 All node multicast
 Global anonymous
 Global published

Source Address Selection Rules
 Rule 1: Prefer same address
 Rule 2: Prefer appropriate scope
 Smallest matching scope
 Rule 3: Avoid deprecated addresses
 Rule 4: Prefer home addresses
 Rule 5: Prefer outgoing interface
 Rule 6: Prefer matching label from policy table
 Native IPv6 source > native IPv6 destination
 6to4 source > 6to4 destination
 IPv4-compatible source > IPv4-compatible destination
 IPv4-mapped source> IPv4-mapped destination
 Rule 7: Prefer temporary addresses
 Rule 8: Use longest matching prefix
 Local policy may override

Destination Address Selection
Rules
 Rule 1: Avoid unusable destinations
 Rule 2: Prefer matching scope
 Rule 3: Avoid dst with matching deprecated src address
 Rule 4: Prefer home addresses
 Rule 5: Prefer matching label from policy table
 Native IPv6 source > native IPv6 destination
 6to4 source > 6to4 destination
 IPv4-compatible source > IPv4-compatible destination
 IPv4-mapped source> IPv4-mapped destination
 Rule 6: Prefer higher precedence
 Rule 7: Prefer smaller scope
 Rule 8: Use longest matching prefix
 Rule 9: Order returned by DNS
 Local policy may override

Address Type Prefixes
Address type Binary prefix
IPv4-compatible 0000...0 (96 zero bits)
global unicast 001
link-local unicast 1111 1110 10
site-local unicast 1111 1110 11
multicast 1111 1111
 all other prefixes reserved (approx. 7/8ths of total)
 anycast addresses allocated from unicast prefixes

site
topology
(16 bits)
interface
identifier
(64 bits)
public
topology
(45 bits)
interface ID
SLA*
NLA*
TLA
001
Global Unicast Addresses
 TLA = Top-Level Aggregator
NLA* = Next-Level Aggregator(s)
SLA* = Site-Level Aggregator(s)
 all subfields variable-length, non-self-encoding (like
CIDR)
 TLAs may be assigned to providers or exchanges

Link-local addresses for use during auto-configuration
and when no routers are present:
Site-local addresses for independence from changes
of TLA / NLA*:
Link-Local & Site-Local Unicast
Addresses
1111111010 0 interface ID
1111111011 0 interface ID
SLA*

Interface IDs
Lowest-order 64-bit field of unicast address
may be assigned in several different ways:
 auto-configured from a 64-bit EUI-64, or expanded
from a 48-bit MAC address (e.g., Ethernet address)
 auto-generated pseudo-random number
(to address privacy concerns)
 assigned via DHCP
 manually configured
 possibly other methods in the future

Some Special-Purpose Unicast
Addresses
 The unspecified address, used as a placeholder when
no address is available:
0:0:0:0:0:0:0:0
 The loopback address, for sending packets to self:
0:0:0:0:0:0:0:1

Multicast Address Format
 flag field
 low-order bit indicates permanent/transient group
 (three other flags reserved)
 scope field:
 1 - node local 8 - organization-local
 2 - link-local B - community-local
 5 - site-local E - global
 (all other values reserved)
 map IPv6 multicast addresses directly into low order 32
bits of the IEEE 802 MAC
FP (8bits) Flags (4bits) Scope (4bits) Group ID (32bits)
11111111 000T Lcl/Sit/Gbl Locally administered
RESERVED (80bits)
MUST be 0

Multicast Address Format
Unicast-Prefix based
 P = 1 indicates a multicast address that is assigned based on the
network prefix
 plen indicates the actual length of the network prefix
 Source-specific multicast addresses is accomplished by setting
 P = 1
 plen = 0
 network prefix = 0
 draft-ietf-ipngwg-uni-based-mcast-01.txt
FP (8bits) Flags (4bits) Scope (4bits) Group ID (32bits)
11111111 00PT Lcl/Sit/Gbl Auto configured
reserved (8bits)
MUST be 0
plen (8bits)
Locally
administered
Network Prefix
(64bits)
Unicast prefix

IPv6 Security
 All implementations required to support
authentication and encryption headers (“IPsec”)
 Authentication separate from encryption for use
in situations where encryption is prohibited or
prohibitively expensive
 Key distribution protocols are under
development (independent of IP v4/v6)
 Support for manual key configuration required

Authentication Header
 Destination Address + SPI identifies security
association state (key, lifetime, algorithm, etc.)
 Provides authentication and data integrity for all fields
of IPv6 packet that do not change en-route
 Default algorithm is Keyed MD5
Next Header Hdr Ext Len
Security Parameters Index (SPI)
Reserved
Sequence Number
Authentication Data

Encapsulating Security Payload
(ESP)
Payload
Next Header
Security Parameters Index (SPI)
Sequence Number
Authentication Data
Padding Length
Padding

IP Quality of Service Approaches
Two basic approaches developed by IETF:
 “Integrated Service” (int-serv)
 fine-grain (per-flow), quantitative promises
(e.g., x bits per second), uses RSVP signaling
 “Differentiated Service” (diff-serv)
 coarse-grain (per-class), qualitative promises
(e.g., higher priority), no explicit signaling

IPv6 Support for Int-Serv
20-bit Flow Label field to identify specific
flows needing special QoS
 each source chooses its own Flow Label
values; routers use Source Addr + Flow
Label to identify distinct flows
 Flow Label value of 0 used when no special
QoS requested (the common case today)
 this part of IPv6 is not standardized yet, and
may well change semantics in the future

IPv6 Support for Diff-Serv
8-bit Traffic Class field to identify specific
classes of packets needing special QoS
 same as new definition of IPv4 Type-of-
Service byte
 may be initialized by source or by router
enroute; may be rewritten by routers enroute
 traffic Class value of 0 used when no special
QoS requested (the common case today)

Compromise
 Signaled diff-serv (RFC 2998)
 uses RSVP for signaling with course-grained
qualitative aggregate markings
 allows for policy control without requiring per-router
state overhead

IPv6 Mobility
 Mobile hosts have one or more home address
 relatively stable; associated with host name in DNS
 A Host will acquire a foreign address when it discovers it
is in a foreign subnet (i.e., not its home subnet)
 uses auto-configuration to get the address
 registers the foreign address with a home agent,
i.e, a router on its home subnet
 Packets sent to the mobile’s home address(es) are
intercepted by home agent and forwarded to the foreign
address, using encapsulation
 Mobile IPv6 hosts will send binding-updates to
correspondent to remove home agent from flow

Mobile IP (v4 version)
home agent
home location of mobile host
foreign agent
mobile host
correspondent
host

Mobile IP (v6 version)
home agent
home location of mobile host
mobile host
correspondent
host

RIPng
 RIPv2, supports split-horizon with
poisoned reverse
 RFC2080

BGP4+ Overview
 Added IPv6 address-family
 Added IPv6 transport
 Runs within the same process - only one
AS supported
 All generic BGP functionality works as for
IPv4
 Added functionality to route-maps and
prefix-lists

IPv6 routing
 OSPF & ISIS updated for IPv6

Effects on higher layers
 Changes TCP/UDP checksum “pseudo-header”
 Affects anything that reads/writes/stores/passes IP
addresses (just about every higher protocol)
 Packet lifetime no longer limited by IP layer
(it never was, anyway!)
 Bigger IP header must be taken into account when
computing max payload sizes
 New DNS record type: AAAA and (new) A6
 …

Sockets API Changes
 Name to Address Translation Functions
 Address Conversion Functions
 Address Data Structures
 Wildcard Addresses
 Constant Additions
 Core Sockets Functions
 Socket Options
 New Macros

Core Sockets Functions
 Core APIs
Use IPv6 Family and Address Structures
socket() Uses PF_INET6
 Functions that pass addresses
bind()
connect()
sendmsg()
sendto()
 Functions that return addresses
accept()
recvfrom()
recvmsg()
getpeername()
getsockname()

Name to Address Translation
 getaddrinfo()
 Pass in nodename and/or servicename string
 Can Be Address and/or Port
 Optional Hints for Family, Type and Protocol
 Flags – AI_PASSIVE, AI_CANNONNAME, AI_NUMERICHOST,
AI_NUMERICSERV, AI_V4MAPPED, AI_ALL, AI_ADDRCONFIG
 Pointer to Linked List of addrinfo structures Returned
 Multiple Addresses to Choose From
 freeaddrinfo()
struct addrinfo {
int ai_flags;
int ai_family;
int ai_socktype;
int ai_protocol;
size_t ai_addrlen;
char *ai_canonname;
struct sockaddr *ai_addr;
struct addrinfo *ai_next;
};
int getaddrinfo(
IN const char FAR * nodename,
IN const char FAR * servname,
IN const struct addrinfo FAR * hints,
OUT struct addrinfo FAR * FAR * res
);

Address to Name Translation
 getnameinfo()
 Pass in address (v4 or v6) and port
 Size Indicated by salen
 Also Size for Name and Service buffers (NI_MAXHOST, NI_MAXSERV)
 Flags
 NI_NOFQDN
 NI_NUMERICHOST
 NI_NAMEREQD
 NI_NUMERICSERV
 NI_DGRAM
int getnameinfo(
IN const struct sockaddr FAR * sa,
IN socklen_t salen,
OUT char FAR * host,
IN size_t hostlen,
OUT char FAR * serv,
IN size_t servlen,
IN int flags
);

Porting Environments
 Node Types
 IPv4-only
 IPv6-only
 IPv6/IPv4
 Application Types
 IPv6-unaware
 IPv6-capable
 IPv6-required
 IPv4 Mapped Addresses

Porting Issues
 Running on ANY System
 Including IPv4-only
 Address Size Issues
 New IPv6 APIs for IPv4/IPv6
 Ordering of API Calls
 User Interface Issues
 Higher Layer Protocol Changes

Specific things to look for
 Storing IP address in 4 bytes of an array.
 Use of explicit dotted decimal format in UI.
 Obsolete / New:
 AF_INET replaced by AF_INET6
 SOCKADDR_IN replaced by SOCKADDR_STORAGE
 IPPROTO_IP replaced by IPPROTO_IPV6
 IP_MULTICAST_LOOP replaced by SIO_MULTIPOINT_LOOPBACK
 gethostbyname replaced by getaddrinfo
 gethostbyaddr replaced by getnameinfo

IPv6 literal addresses in URL’s
 From RFC 2732
Literal IPv6 Address Format in URL's Syntax To use a literal IPv6 address in a
URL, the literal address should be enclosed in "[" and "]" characters. For
example the following literal IPv6 addresses:
FEDC:BA98:7654:3210:FEDC:BA98:7654:3210
3ffe:2a00:100:7031::1
::192.9.5.5
2010:836B:4179::836B:4179
would be represented as in the following example URLs:
http://[FEDC:BA98:7654:3210:FEDC:BA98:7654:3210]:80/index.html
http://[3ffe:2a00:100:7031::1]
http://[::192.9.5.5]/ipng
http://[2010:836B:4179::836B:4179]

Other Issues
 Renumbering & Mobility routinely result in changing IP
Addresses –
 Use Names and Resolve, Don’t Cache
 Multihomed Servers
 More Common with IPv6
 Try All Addresses Returned
 Using New IPv6 Functionality

Porting Steps -Summary
 Use IPv4/IPv6 Protocol/Address Family
 Fix Address Structures
in6_addr
sockaddr_in6
sockaddr_storage to allocate storage
 Fix Wildcard Address Use
in6addr_any, IN6ADDR_ANY_INIT
in6addr_loopback, IN6ADDR_LOOPBACK_INIT
 Use IPv6 Socket Options
IPPROTO_IPV6, Options as Needed
 Use getaddrinfo()
For Address Resolution

IPv4 - IPv6
Co-Existence / Transition

IPv6 Timeline
(A pragmatic projection)
Q
1
Q
2
Q
3
Q
4
2007
Q
1
Q
2
Q
3
Q
4
2004
Q
1
Q
2
Q
3
Q
4
2003
Q
1
Q
2
Q
3
Q
4
2000
Q
1
Q
2
Q
3
Q
4
2001
Q
1
Q
2
Q
3
Q
4
2002
Q
1
Q
2
Q
3
Q
4
2005
Q
1
Q
2
Q
3
Q
4
2006
• Consumer adoption <= Duration 5+ years
• Application porting <= Duration 3+ years
• Early adopter
=>
=>
• Enterprise adoption <= Duration 3+ years =>
=>
adoption <= Duration 3+ years
• ISP

Deployments
 IPv6 deployments will occur piecewise
from the edge.
 Core infrastructure only moving when
significant customer usage demands it.
 Platforms and products that are updated first
need to address the lack of ubiquity.
Whenever possible, devices and applications
should be capable of both IPv4 & IPv6, to
minimize the delays and potential failures
inherent in translation points.

Impediments to IPv6 deployment
 Applications
 Applications
 Applications
 Move to the new APIs NOW

Transition / Co-Existence Techniques
A wide range of techniques have been identified and implemented,
basically falling into three categories:
 (1) dual-stack techniques, to allow IPv4 and IPv6 to
co-exist in the same devices and networks
 (2) tunneling techniques, to avoid order
dependencies when upgrading hosts, routers, or
regions
 (3) translation techniques, to allow IPv6-only
devices to communicate with IPv4-only devices
Expect all of these to be used, in combination

Dual-Stack Approach
 When adding IPv6 to a system, do not delete IPv4
 this multi-protocol approach is familiar and
well-understood (e.g., for AppleTalk, IPX, etc.)
 note: in most cases, IPv6 will be bundled with
new OS releases, not an extra-cost add-on
 Applications (or libraries) choose IP version to use
 when initiating, based on DNS response:
Prefer scope match first, when equal IPv6 over IPv4
 when responding, based on version of initiating packet
 This allows indefinite co-existence of IPv4 and IPv6, and gradual
app-by-app upgrades to IPv6 usage

Tunnels to Get Through
IPv6-Ignorant Routers
 Encapsulate IPv6 packets inside IPv4 packets
(or MPLS frames)
 Many methods exist for establishing tunnels:
 manual configuration
 “tunnel brokers” (using web-based service to create a tunnel)
 automatic (depricated, using IPv4 as low 32bits of IPv6)
 “6-over-4” (intra-domain, using IPv4 multicast as virtual LAN)
 “6-to-4” (inter-domain, using IPv4 addr as IPv6 site prefix)
 Can view this as:
 IPv6 using IPv4 as a virtual NBMA link-layer, or
 an IPv6 VPN (virtual public network), over the IPv4 Internet

Translation
 May prefer to use IPv6-IPv4 protocol translation for:
 new kinds of Internet devices (e.g., cell phones, cars,
appliances)
 benefits of shedding IPv4 stack (e.g., serverless
autoconfig)
 This is a simple extension to NAT techniques, to
translate header format as well as addresses
 IPv6 nodes behind a translator get full IPv6 functionality
when talking to other IPv6 nodes located anywhere
 they get the normal (i.e., degraded) NAT functionality when
talking to IPv4 devices
 drawback : minimal gain over IPv4/IPv4 NAT approach

Tunnels
 6to4
 Configured
 Automatic

6to4 tunnels
IPv4
IPv6 IPv6
6to4 prefix is 2002::/16 + IPv4 address.
2002:a.b.c.d::/48 IPv6 Internet
6to4 relay
2002:B00:1::1
Announces 2002::/16 to the IPv6 Internet
130.67.0.1 148.122.0.1
11.0.0.1
2002:8243:1::/48
2002:947A:1::/48
FP (3bits) TLA (13bits) IPv4 Address (32bits) SLA ID (16bits) Interface ID (64bits)
001 0x0002 ISP assigned Locally administered Auto configured

6to4 tunnels II
Pros Cons
Minimal configuration All issues that NMBA
networks have.
Only site border router
needs to know about 6to4
Requires relay router to
reach native IPv6 Internet
Works without adjacent
native IPv6 routers
Has to use 6to4
addresses, not native.
NB: there is a draft describing how to use IPv4 anycast to reach the relay router.
(This is already supported, by our implementation...)

Configured tunnels
IPv4
IPv6 IPv6
3ffe:c00:1::/48
3ffe:c00:2::/48
130.67.0.1 148.122.0.1
--------------------------------------
|IPv4 header|IPv6 header IPv6 payload|
--------------------------------------
IPv4 protocol type = 41

Configured tunnels II
Pros Cons
As point to point links Has to be configured and
managed
Multicast Inefficient traffic patterns
Real addresses No keepalive mechanism,
interface is always up

Automatic tunnels
IPv4
IPv6 IPv6
Connects dual stacked nodes
Quite obsolete
IPv6 Internet
130.67.0.1
::130.67.0.1
148.122.0.1
::148.122.0.1
IPv4 Address (32bits)
ISP assigned
Defined
0

Automatic tunnels II
Pros Cons
Obsolete Difficult to reach the native
IPv6 Internet, without
injecting IPv4 routing
information in the IPv6
routing table
Useful for some other
mechanisms, like BGP
tunnels
Has to use IPv4
compatible addresses

Tunneling issues
 IPv4 fragmentation needs to be reconstructed at
tunnel endpoint.
 No translation of Path MTU messages between
IPv4 & IPv6.
 Translating IPv4 ICMP messages and pass back
to IPv6 originator.
 May result in an inefficient topology.

Tunneling issues II
 Tunnel interface is always up. Use routing
protocol to determine link failures.
 Be careful with using the same IPv4 source
address for several tunneling mechanisms.
Demultiplexing incoming packets is difficult.

Deployment scenarios
 Many ways to deliver IPv6 services to End Users
 Most important is End to End IPv6 traffic forwarding
 Service Providers and Enterprises may have
different deployment needs
 IPv6 over IPv4 tunnels
 Dedicated Data Link layers for native IPv6
 no impact on IPv4 traffic & revenues
 Dual stack Networks
 IPv6 over MPLS or IPv4-IPv6 Dual Stack Routers

Media - Interface Identifier
 IEEE interfaces - EUI-64
 MAC-address: 0050.a218.0c38
 Interface ID: 250:A2FF:FE18:C38
 P2P links (HDLC, PPP)
 Interface ID: 50:A218:C00:D
 48 bits from the first MAC address in the box + 16
bit interface index. U/L bit off
 IPv4 tunnels
 Interface ID: ::a.b.c.d

Standards
 core IPv6 specifications are IETF Draft
Standards
=> well-tested & stable
 IPv6 base spec, ICMPv6, Neighbor Discovery, PMTU
Discovery, IPv6-over-Ethernet, IPv6-over-PPP,...
 other important specs are further behind on the
standards track, but in good shape
 mobile IPv6, header compression, A6 DNS support,...
 for up-to-date status: playground.sun.com/ipng
 UMTS R5 cellular wireless standards mandate
IPv6

Implementations
 Most IP stack vendors have an implementation
at some stage of completeness
 some are shipping supported product today,
e.g., 3Com, *BSD(KAME), Cisco, Epilogue,
Ericsson/Telebit, IBM, Hitachi, NEC, Nortel, Sun, Trumpet
 others have beta releases now, supported products soon,
e.g., Compaq, HP, Linux community, Microsoft
 others rumored to be implementing, but status unkown (to
me), e.g., Apple, Bull, Juniper, Mentat, Novell, SGI
 (see playground.sun.com/ipng for most recent status
reports)
 Good attendance at frequent testing events

IPv6 Addresses
Bootstrap phase
 Where to get address space?
 Real IPv6 address space now allocated
by APNIC, ARIN and RIPE NCC
 APNIC 2001:0200::/23
 ARIN 2001:0400::/23
 RIPE NCC 2001:0600::/23
 6Bone 3FFE::/16
Have a look at www.cisco.com/ipv6 for further information

IPv6 Address Space
Current Allocations
 APNIC (whois.apnic.net)
CONNECT-AU-19990916 2001:210::/35
WIDE-JP-19990813 2001:200::/35
NUS-SG-19990827 2001:208::/35
KIX-KR-19991006 2001:220::/35
ETRI-KRNIC-KR-19991124 2001:230::/35
NTT-JP-19990922 2001:218::/35
HINET-TW-20000208 2001:238::/35
IIJ-JPNIC-JP-20000308 2001:240::/35
CERNET-CN-20000426 2001:250::/35
INFOWEB-JPNIC-JP-2000502 2001:258::/35
JENS-JP-19991027 2001:228::/35
BIGLOBE-JPNIC-JP-20000719 2001:260::/35
6DION-JPNIC-JP-20000829 2001:268::/35
DACOM-BORANET-20000908 2001:270::/35
ODN-JPNIC-JP-20000915 2001:278::/35
KOLNET-KRNIC-KR-20000927 2001:280::/35
HANANET-KRNIC-KR-20001030 2001:290::/35
TANET-TWNIC-TW-20001006 2001:288::/35
January 5th, 2001
SONYTELECOM-JPNIC-JP-20001207 2001:298::/35
TTNET-JPNIC-JP-20001208 2001:2A0::/35
CCCN-JPNIC-JP-20001228 2001:02A8::/35
IMNET-JPNIC-JP-20000314 2001:0248::/35
KORNET-KRNIC-KR-20010102 2001:02B0::/35
 ARIN (whois.arin.net)
ESNET-V6 2001:0400::/35
ARIN-001 2001:0400::/23
VBNS-IPV6 2001:0408::/35
CANET3-IPV6 2001:0410::/35
VRIO-IPV6-0 2001:0418::/35
CISCO-IPV6-1 2001:0420::/35
QWEST-IPV6-1 2001:0428::/35
DEFENSENET 2001:0430::/35
ABOVENET-IPV6 2001:0438::/35
SPRINT-V6 2001:0440::/35
UNAM-IPV6 2001:0448::/35
GBLX-V6 2001:0450::/35

IPv6 Address Space
Current Allocations
 RIPE (whois.ripe.net)
UK-BT-19990903 2001:0618::/35
CH-SWITCH-19990903 2001:0620::/35
AT-ACONET-19990920 2001:0628::/35
UK-JANET-19991019 2001:0630::/35
DE-DFN-19991102 2001:0638::/35
NL-SURFNET-19990819 2001:0610::/35
RU-FREENET-19991115 2001:0640::/35
GR-GRNET-19991208 2001:0648::/35
EU-UUNET-19990810 2001:0600::/35
DE-TRMD-20000317 2001:0658::/35
FR-RENATER-20000321 2001:0660::/35
EU-EUNET-20000403 2001:0670::/35
DE-IPF-20000426 2001:0678::/35
DE-NACAMAR-20000403 2001:0668::/35
DE-XLINK-20000510 2001:0680::/35
DE-ECRC-19991223 2001:0650::/35
FR-TELECOM-20000623 2001:0688::/35
PT-RCCN-20000623 2001:0690::/35
SE-SWIPNET-20000828 2001:0698::/35
PL-ICM-20000905 2001:06A0::/35
DE-SPACE-19990812 2001:0608::/35
BE-BELNET-20001101 2001:06A8::/35
SE-SUNET-20001218 2001:06B0::/35
IT-CSELT-20001221 2001:06B8::/35
SE-TELIANET-20010102 2001:06C0::/35

Deployment
 experimental infrastructure: the 6bone
 for testing and debugging IPv6 protocols and
operations (see www.6bone.net)
 production infrastructure in support of education
and research: the 6ren
 CAIRN, Canarie, CERNET, Chunahwa Telecom,
Dante, ESnet, Internet 2, IPFNET, NTT, Renater,
Singren, Sprint, SURFnet, vBNS, WIDE
(see www.6ren.net, www.6tap.net)
 commercial infrastructure
 a few ISPs (IIJ, NTT, SURFnet, Trumpet,…) have
announced commercial IPv6 service or service trials

Deployment (cont.)
 IPv6 address allocation
 6bone procedure for test address space
 regional IP address registries (APNIC, ARIN,
RIPE-NCC) for production address space
 deployment advocacy (a.k.a. marketing)
 IPv6 Forum: www.ipv6forum.com

Much Still To Do
though IPv6 today has all the functional capability of IPv4,
 implementations are not as advanced
(e.g., with respect to performance, multicast support,
compactness, instrumentation, etc.)
 deployment has only just begun
 much work to be done moving application, middleware,
and management software to IPv6
 much training work to be done
(application developers, network administrators, sales
staff,…)
 many of the advanced features of IPv6 still need
specification, implementation, and deployment work

Recent IPv6 “Hot Topics” in the
IETF
 multihoming / address
selection
 address allocation
 DNS discovery
 3GPP usage of IPv6
 anycast addressing
 scoped address
architecture
 flow-label semantics
 API issues
 (flow label, traffic class, PMTU
discovery, scoping,…)
 enhanced router-to-host info
 site renumbering procedures
 temp. addresses for privacy
 inter-domain multicast routing
 address propagation and AAA
issues of different access
scenarios
 (always-on, dial-up, mobile,…)
 and, of course, transition /
co-existence / interoperability
with IPv4
Note: this indicates vitality, not incompleteness, of IPv6!

For More Information
 http://www.ietf.org/html.charters/ipngwg-
charter.html
 http://www.ietf.org/html.charters/ngtrans-
charter.html
 http://playground.sun.com/ipv6/
 http://www.6bone.net/ngtrans/

 http://www.6bone.net
 http://www.ipv6forum.com
 http://www.ipv6.org
 http://www.cisco.com/ipv6/
 http://www.microsoft.com/windows2000/librar
y/howitworks/communications/networkbasics/
IPv6.asp

 BGP4+ References
 RFC2858 Multiprotocol extension to BGP
RFC2545 BGP MP for IPv6
RFC2842 Capability negotiation
 RIPng RFC2080

Other Sources of Information
 Books
 IPv6, The New Internet Protocol
by Christian Huitema (Prentice Hall)
 Internetworking IPv6 with Cisco Routers
by Silvano Gai (McGraw-Hill)
 and many more... (14 hits at Amazon.com)

Curs_IPv6.ppt

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