IPv6 - Benefits and Deployment Issues

VIΔίκτυα και Επικοινωνίες

14 Οκτ 2011 (πριν από 5 χρόνια και 10 μήνες)

636 εμφανίσεις

Dr. Chris Edwards Lancaster University, UK ce@comp.lancs.ac.uk

IPv6
IPv6
-
-
Benefits and
Benefits and
Deployment Issues
Deployment Issues
Dr. Chris Edwards
Dr. Chris Edwards
Lancaster University, UK
Lancaster University, UK
ce@comp.lancs.ac.uk
ce@comp.lancs.ac.uk
Agenda for Today
Agenda for Today


Introduction to IPv6
Introduction to IPv6


Benefits of IPv6
Benefits of IPv6


Deployment Issues
Deployment Issues


Transitioning
Transitioning


A full service?
A full service?
Networking Today
Networking Today


Severe shortage of IP addresses
Severe shortage of IP addresses


Limits growth for existing users
Limits growth for existing users


Hinders use for new users
Hinders use for new users


Routing table explosion
Routing table explosion


Management nightmare
Management nightmare


No support for new applications
No support for new applications


Mobility, QoS, etc…
Mobility, QoS, etc…


Drive for
Drive for
commercialisation
commercialisation
killed network exp.
killed network exp.
What is IPv6
What is IPv6


IETF standard for the next generation
IETF standard for the next generation
IP
IP


AKA
AKA
IPng
IPng


Design goals
Design goals


Address the failings of IPv4
Address the failings of IPv4


Namely:
Namely:


Scalability
Scalability


Efficiency
Efficiency


Extensibility
Extensibility
IP and Scalability…
IP and Scalability…


IPv4 lacks scalability due to addressing
IPv4 lacks scalability due to addressing


32 bits address space (4.4
32 bits address space (4.4
Bn
Bn
addresses)
addresses)


Most addresses allocated to US
Most addresses allocated to US


More addresses, please!
More addresses, please!


Individually address all mobile handsets
Individually address all mobile handsets


Growth of “always on”, globally addressable devices
Growth of “always on”, globally addressable devices


Peer
Peer
-
-
to
to
-
-
peer computing, e.g. ICQ, video/
peer computing, e.g. ICQ, video/
VoIP
VoIP


Home networking appliances, pervasive computing
Home networking appliances, pervasive computing
devices
devices
Users on the Internet
Users on the Internet


September 2002
September 2002
CAN/
US
Euro
pe
A
sia/Pac
La
tin A
m
Afri
ca
Mi
d Ea
s
t


CAN/US
CAN/US
182.67M
182.67M


Europe
Europe
190.92M
190.92M


Asia/Pac
Asia/Pac
187.24M
187.24M


Latin Am
Latin Am
33.35M
33.35M


Africa
Africa
6.31M
6.31M


Mid
Mid
-
-
east
east
5.12M
5.12M
---------------------------
---------------------------


Total
Total
605.6 M
605.6 M
Thanks to Vint
Cerf, WorldCom, and www.nua.com
Internet User Trends
Internet User Trends
0
500
1000
1500
2000
2500
1995
1997
1
999
2001
200
3
2005
2007
2
009
Year
Users (Millions)
Source: Nua
Internet Surveys + Vint
Cerf
predictions
More Predictions…
More Predictions…
0
200
400
600
800
1000
1200
1400
1600
1989_
199
1_
199
3_
1995_
1997_
1999_
2001_
2003_
2005_
hos
ts
mobiles
605 Million users
Source:
Source:
Cerf
Cerf
, based on
, based on
www.nw.com
www.nw.com
, Jun 2000 + Ericsson
, Jun 2000 + Ericsson
IPv6
IPv6


Size Matters…
Size Matters…


Extended address space
Extended address space


128 bits long
128 bits long


Unicast
Unicast
, Multicast or Anycast formats
, Multicast or Anycast formats


Written in hex notation as 16
Written in hex notation as 16
-
-
bit integers
bit integers


E.g. 2001:630:80:0:0:0:0:1
E.g. 2001:630:80:0:0:0:0:1


3.4 x 10
3.4 x 1038
38
Addresses
Addresses


6.7 x 10
6.7 x 1023
23
Addresses / m
Addresses / m
2
2
on the earth
on the earth
IPv6 Addressing Model
IPv6 Addressing Model


Addresses are assigned to interfaces
Addresses are assigned to interfaces


Interfaces can have multiple addresses
Interfaces can have multiple addresses


Addresses have scope:
Addresses have scope:
link local
link local
,
,
site local
site local
,
,
global
global


Addresses are formed through the
Addresses are formed through the
combination of:
combination of:


Routing Prefix
Routing Prefix


where you are connected to
where you are connected to


Interface ID
Interface ID


who you are
who you are
Aggregatable Addresses
Aggregatable Addresses
2001:0630:0080:7030:0000:0000:0000:0001/64
F
ormat prefix
3 bits (001)
Reserved
8 bits
Prefix length
13
24
16
64
TLA
NLA
SLA
Interface ID
TLA
Top Level Aggregation identifier
NLA
Next Level Aggregation identifier
SLA
Site Level Aggregation identifier
IPv6 terminology can drop a single string of all 0s…
2001:630:80:7030::1/64
2001:630:80:7030::/64
loopback
::1
unspecified ::0
IPv4 Compatible
::148.88.8.6
IPv6 General Concepts
IPv6 General Concepts


Improved routing techniques
Improved routing techniques


Aggregated routing entries designed to
Aggregated routing entries designed to
reduce routing table sizes
reduce routing table sizes


Multicast supported as native
Multicast supported as native
communication mode
communication mode


Authentication and privacy capabilities
Authentication and privacy capabilities


Authentication header
Authentication header


Transport + Tunnel Mode
Transport + Tunnel Mode
Efficient Header
Efficient Header
Construction
Construction


IPv4 contains many redundant features…
IPv4 contains many redundant features…


Variable length IP header options
Variable length IP header options


IP header checksum
IP header checksum


…some inefficient ones…
…some inefficient ones…


Packet fragmentation
Packet fragmentation


… and some omitted
… and some omitted


Packet classification
Packet classification


All of which impact network performance
All of which impact network performance
IP: Head to Head
IP: Head to Head
+-
+-
+-
+-+-+-+-+-+-+-
+-
+-
+-
+-+-+
-+-+-+-+-+-+-+
-+
-+
-+
-+-+-+-+-+-+-+
|V
er
si
on| IH
L |Typ
e
of
S
ervic
e| To
ta
l
Le
ngth |
+-
+-
+-
+-+-+-+-+-+-+-
+-
+-
+-
+-+-+
-+-+-+-+-+-+-+
-+
-+
-+
-+-+-+-+-+-+-+
|


Identifica
ti
on



|
Flags| Frag
me
nt
O
ffset
|
+-
+-
+-
+-+-+-+-+-+-+-
+-
+-
+-
+-+-+
-+-+-+-+-+-+-+
-+
-+
-+
-+-+-+-+-+-+-+
|
Time to Live
|


Pr
otocol |
He
ad
er Checksum |
+-
+-
+-
+-+-+-+-+-+-+-
+-
+-
+-
+-+-+
-+-+-+-+-+-+-+
-+
-+
-+
-+-+-+-+-+-+-+
|



So
urce Address




|
+-
+-
+-
+-+-+-+-+-+-+-
+-
+-
+-
+-+-+
-+-+-+-+-+-+-+
-+
-+
-+
-+-+-+-+-+-+-+
|



D
es
ti
na
tio
n Ad
dress


|
+-
+-
+-
+-+-+-+-+-+-+-
+-
+-
+-
+-+-+
-+-+-+-+-+-+-+
-+
-+
-+
-+-+-+-+-+-+-+
|



O
pt
io
ns




|
Padding |
+-
+-
+-
+-+-+-+-+-+-+-
+-
+-
+-
+-+-+
-+-+-+-+-+-+-+
-+
-+
-+
-+-+-+-+-+-+-
+
0



1

2

3

0 1 2 3 4 5 6 7 8 9 0 1 2 3 4
5 6 7 8 9
0
1

2

3
4
5 6 7 8 9 0 1
IP: Head to Head
IP: Head to Head
+-
+-
+-
+-+-+-+-+-+-+-
+-
+-
+-
+-+-+
-+
-+-+-+-+-+-+
-+
-+
-+
-+
-+-+-+-+-+-+
|V
er
si
on| Traffic Cl
as
s | Flow Labe
l |
+-
+-
+-
+-+-+-+-+-+-+-
+-
+-
+-
+-+-+
-+
-+-+-+-+-+-+
-+
-+
-+
-+
-+-+-+-+-+-+
|


Payload Le
ng
th



|
Next Heade
r
|

H
op Limi
t |
+-
+-
+-
+-+-+-+-+-+-+-
+-
+-
+-
+-+-+
-+
-+-+-+-+-+-+
-+
-+
-+
-+
-+-+-+-+-+-+
|









|
+









+
|









|
+




Sourc
e
Address




+
|









|
+









+
|









|
+-
+-
+-
+-+-+-+-+-+-+-
+-
+-
+-
+-+-+
-+
-+-+-+-+-+-+
-+
-+
-+
-+
-+-+-+-+-+-+
|









|
+









+
|
















|
+




D
es
ti
nat
io
n Address


+
|









|
+









+
|









|
+-
+-
+-
+-+-+-+-+-+-+-
+-
+-
+-
+-+-+
-+
-+-+-+-+-+-+
-+
-+
-+
-+
-+-+-+-+-+-+
0



1


2

3

0 1 2 3 4 5 6 7 8 9 0 1 2 3 4
5
6 7 8 9
0
1

2

3
4
5 6 7 8 9 0 1
What’s missing?
What’s missing?


The IPv6 protocol header is
The IPv6 protocol header is
streamlined for the common
streamlined for the common
-
-
case…
case…


Fixed format header (no options)
Fixed format header (no options)


No
No
checksum
checksum
-
-
left to transport and
left to transport and
data link layers, no need to
data link layers, no need to
check/recalculate each hop
check/recalculate each hop


No fragmentation (except at source)
No fragmentation (except at source)


Agree path
Agree path
MTU
MTU
at the source using
at the source using
Path
Path
MTU discovery
MTU discovery
What’s new
What’s new


Revised fields
Revised fields


Payload length
Payload length
vs.
vs.
Total length
Total length


Next Header
Next Header
vs.
vs.
Protocol type
Protocol type


Hop Limit
Hop Limit
vs.
vs.
TTL
TTL


New fields
New fields


Traffic Class
Traffic Class
:
:


To support differentiated services (e.g.
To support differentiated services (e.g.
prioritised best effort queuing)
prioritised best effort queuing)


Flow Label
Flow Label
:
:


Along with source address, allows identification
Along with source address, allows identification
of packets which are part of a ‘flow’
of packets which are part of a ‘flow’
Extensible headers
Extensible headers


Custom headers for specialist
Custom headers for specialist
functionality…
functionality…


Fragmentation Headers
Fragmentation Headers


Routing Headers
Routing Headers


Destination Options
Destination Options


Hop by Hop Headers
Hop by Hop Headers


Authentication and ESP
Authentication and ESP
IPv6 Extension Headers
IPv6 Extension Headers


In IPv6, Options are daisy
In IPv6, Options are daisy
-
-
chained in
chained in
extension headers…
extension headers…
IPv6 Header
Next header
= TCP
TCP Header + Data
IPv6 Header
Next hea
der =
Routing
Routing Hdr
Next hea
der =
TCP
TCP Header + Data
Fragment of TCP
Header + Data
IPv6 Header
Next hea
der =
Routing
Routing Hdr
Next hea
der =
Fragment
Fragment Hdr
Next hea
der =
TCP
Autoconfiguration
Autoconfiguration


Plug ‘n’ Play Networking…
Plug ‘n’ Play Networking…


IPv6 host requires three pieces of info
IPv6 host requires three pieces of info


IPv6 Address
IPv6 Address


IPv6 Network
IPv6 Network


IPv6 Gateway
IPv6 Gateway


Router Solicitation and Advertisement…
Router Solicitation and Advertisement…
Router Solicitation
Autoconfiguration
Autoconfiguration


Plug ‘n’ Play Networking…
Plug ‘n’ Play Networking…


IPv6 host requires three pieces of info
IPv6 host requires three pieces of info


IPv6 Address
IPv6 Address


IPv6 Network
IPv6 Network


IPv6 Gateway
IPv6 Gateway


Router Solicitation and Advertisement…
Router Solicitation and Advertisement…
Router Advertisement
2001:630:80:7000::/64
Autoconfiguration
Autoconfiguration


Host builds IPv6 address from prefix
Host builds IPv6 address from prefix


Using EUI
Using EUI
-
-
64 identifier of interface
64 identifier of interface


Or padded MAC address…
Or padded MAC address…


In two frame message exchange
In two frame message exchange
Router Advertisement
2001:630:80:7000::/64
Deployment Issues:
Deployment Issues:
Transitioning to IPv6…
Transitioning to IPv6…
Contrary to popular belief, IPv6 is
Contrary to popular belief, IPv6 is
not
not
backward compatible…
backward compatible…
Compatibility Issues
Compatibility Issues


Introduce IPv6 connectivity into the IPv4 world
Introduce IPv6 connectivity into the IPv4 world


IPv6 hosts must be able to communicate with
IPv6 hosts must be able to communicate with
each other across IPv4 nets
each other across IPv4 nets


As native IPv6 networks become commonplace
As native IPv6 networks become commonplace


IPv4 hosts will need to communicate with each other across IPv6
IPv4 hosts will need to communicate with each other across IPv6
networks
networks


IPv6 hosts will need to communicate with IPv4 hosts
IPv6 hosts will need to communicate with IPv4 hosts


What about dual stacks?
What about dual stacks?
Plugging it Together…
Plugging it Together…


Three broad categories
Three broad categories


Tunnelling
Tunnelling
(6to4, 6over4, Tunnel brokers,
(6to4, 6over4, Tunnel brokers,
Teredo
Teredo
, ISATAP)
, ISATAP)


Allowing hosts that support IPv6 to talk IPv6
Allowing hosts that support IPv6 to talk IPv6
to other IPv6 hosts
to other IPv6 hosts


Translation
Translation
(SIIT, NAT
(SIIT, NAT
-
-
PT, SOCKS, BIS)
PT, SOCKS, BIS)


Translation between the two
Translation between the two


Dual Stack
Dual Stack
(DSTM)
(DSTM)
Dual IP Stacks
Dual IP Stacks


Simplest method: Both stacks in parallel
Simplest method: Both stacks in parallel
in hosts and routers
in hosts and routers


Upgrade routers, and host OS
Upgrade routers, and host OS


Host upgrade can be gradual
Host upgrade can be gradual


Application support:
Application support:


Existing applications continue to run
Existing applications continue to run


IPv6 applications (experimental or not…) can
IPv6 applications (experimental or not…) can
be introduced
be introduced


Interoperation of v4 and v6 is another issue
Interoperation of v4 and v6 is another issue


Applications to be modified to handle both?
Applications to be modified to handle both?
Dual IP Stacks (2)
Dual IP Stacks (2)


Issues
Issues


Solution does not scale:
Solution does not scale:


New IPv6 hosts that need IPv4 compatibility
New IPv6 hosts that need IPv4 compatibility
will quickly eat up IPv4 address space
will quickly eat up IPv4 address space


Two IP routing tables will place a burden on
Two IP routing tables will place a burden on
routers
routers


Entire path dual stack?
Entire path dual stack?


No real stimulus for moving to IPv6
No real stimulus for moving to IPv6
Dual Stack Transition
Dual Stack Transition
Mechanism (DSTM)
Mechanism (DSTM)


Addresses problem of new dual stack hosts
Addresses problem of new dual stack hosts
exhausting sparse IPv4 address space
exhausting sparse IPv4 address space


Allows IPv6 hosts to temporarily acquire an
Allows IPv6 hosts to temporarily acquire an
IPv4 global address
IPv4 global address


Uses a DHCPv6 server within each domain
Uses a DHCPv6 server within each domain


Assigns IPv4 address on temporary basis
Assigns IPv4 address on temporary basis


In instances where IPv6 hosts remain online,
In instances where IPv6 hosts remain online,
temporary assignment becomes permanent…
temporary assignment becomes permanent…
i.e. does not eradicate the problem altogether
i.e. does not eradicate the problem altogether
Tunnelling
Tunnelling


Common mechanism, where one protocol is
Common mechanism, where one protocol is
encapsulated in another
encapsulated in another


IPv6 over IPv4 tunnelling
IPv6 over IPv4 tunnelling


Used to transport IPv6 packets over networks
Used to transport IPv6 packets over networks
that can only understand IPv4
that can only understand IPv4


Normally the most common transition
Normally the most common transition
mechanism adopted in early stages
mechanism adopted in early stages


6BONE is an example of a virtual overlay
6BONE is an example of a virtual overlay
network of interconnected IPv6 over IPv4
network of interconnected IPv6 over IPv4
tunnels
tunnels


Can work in a variety of ways:
Can work in a variety of ways:
host to router
host to router
,
,
router to router
router to router
,
,
router to host
router to host
,
,
host to host
host to host
Tunnelling (2)
Tunnelling (2)


IPv6 over IPv4 tunnels are classified as either
IPv6 over IPv4 tunnels are classified as either
configured
configured
or
or
automatic
automatic
, depending on the way
, depending on the way
the IPv4 address of the endpoint is determined
the IPv4 address of the endpoint is determined


Approaches
Approaches


6to4
6to4


popular, automatic, router to router
popular, automatic, router to router


6over4
6over4


single site, relies on IPv4 multicast
single site, relies on IPv4 multicast


Teredo
Teredo


connectivity to v4 hosts behind NAT
connectivity to v4 hosts behind NAT


ISATAP
ISATAP


site based, where v6 host and gateway is
site based, where v6 host and gateway is
separated
separated


Tunnel brokers
Tunnel brokers


(web
(web
-
-
based) mechanism for
based) mechanism for
obtaining a tunnel
obtaining a tunnel
Translation Tools
Translation Tools


Translation necessary for IPv6
Translation necessary for IPv6
-
-
only and
only and
IPv4
IPv4
-
-
only hosts to communicate, should be
only hosts to communicate, should be
done near network edge
done near network edge


Translates packets from one protocol to
Translates packets from one protocol to
another, taking form of header processing
another, taking form of header processing


Can take place at a number of layers
Can take place at a number of layers


IP layer
IP layer


Transport layer
Transport layer


Application layer
Application layer
Translation Tools (2)
Translation Tools (2)


Series of tools available
Series of tools available


SIIT
SIIT


translates between IPv4 and IPv6 headers
translates between IPv4 and IPv6 headers
using a translation algorithm located in the network
using a translation algorithm located in the network


NAT
NAT
-
-
PT
PT


maintains a pool of unique v4 add. that
maintains a pool of unique v4 add. that
it dynamically allocates to v6 nodes
it dynamically allocates to v6 nodes


BIS
BIS


takes NAT
takes NAT
-
-
PT with SIIT functionality and
PT with SIIT functionality and
moves it to the OS protocol stack within each host
moves it to the OS protocol stack within each host


SOCKS
SOCKS


application layer IPv6/IPv4 gateway
application layer IPv6/IPv4 gateway
based on SOCKS, translating between two
based on SOCKS, translating between two
terminated v4 and v6 connections
terminated v4 and v6 connections
The IPv6 Operations
The IPv6 Operations
IETF Working Group
IETF Working Group
(v6ops)
(v6ops)


Ngtrans
Ngtrans
group closed, replaced by v6ops
group closed, replaced by v6ops


More “operationally oriented”
More “operationally oriented”
wg
wg


Operating the “combined net” + avoiding a division
Operating the “combined net” + avoiding a division


Develop guidelines:
Develop guidelines:


Operation of shared v4/v6 Internet
Operation of shared v4/v6 Internet


How to deploy v6 into both v4
How t
o deploy v6 into both v4-
-
only and new installations
only and new installations


Why?
Why?


V6 is deploying today
V6 is deploying today


V6 has been hiding in a corner of the IETF
V6 has been hiding in a corner of the IETF


Timescales: Oct 2002
Timescales: Oct 2002


Aug 2003
Aug 2003
Deployment Issues:
Deployment Issues:
A full service?
A full service?
The bigger questions
The bigger questions


How long will deployment take?
How long will deployment take?


2 addressing modes co
2 addressing modes co
-
-
existing
existing


5/ 10 / 15 years?
5/ 10 / 15 years?


What support do we have now?
What support do we have now?


Hosts
Hosts


Routers
Routers


Applications
Applications


ISPs
ISPs


(see Tim and Duncan presentation later)
(see Tim and Duncan presentation later)
A Full IPv6 Service?
A Full IPv6 Service?


Production service needs commercial
Production service needs commercial
code
code


Stability, reliability issues
Stability, reliability issues


On backbone
On backbone


Possible now
Possible now


Hardware
Hardware
-
-
enabled?
enabled?


Applications
Applications


Perhaps some way off yet
Perhaps some way off yet
A Full IPv6 Service? (2)
A Full IPv6 Service? (2)


Do we have a significant driver?
Do we have a significant driver?


Less demand where IPv4 address space seen as
Less demand where IPv4 address space seen as
being sufficient
being sufficient


Users will not demand "IPv6" but demand IPv6
Users will not demand "IPv6" but demand IPv6
-
-
based applications
based applications


IPv4 address exhaustion?
IPv4 address exhaustion?


Major network infrastructure deployment (e.g., 3G)
Major network infrastructure deployment (e.g., 3G)


Significant research activities in UK and Europe
Significant research activities in UK and Europe


Universities,
Universities,
NRENs
NRENs
, Consortiums
, Consortiums


UK IPv6 Task Force
UK IPv6 Task Force
Thank you…
Thank you…
Questions?
Questions?