Transcript G3_P2_InteroperabilityBetweenv4and v6

CSE 8343
Group 3
Advanced OS
Inter Operability
Between IPv4 and IPv6
Team Members
Aman Preet Singh
Rohit Singh
Nipun Aggarwal
Chirag Shah
Eugene Novak
CSE 8343
Group 3
Why IPv6 ?
Problems in IPv4
• Shortage of IP addresses
• Variable header size
• No support for Qos
• Security
• Not Plug n Play
IPv6 advantage over IPv4
• Scalability
• Fixed Header
• Quality of Service
• Security
• Plug and play
• Optimization
Advanced OS
Group 3
CSE 8343
Advanced OS
Why Interoperability ?
• IPv6 is a better option
• IPv4 is omnipresent
• Ipv6 is not an upgrade for IPv4
Moral of the story
• Interoperability between IPv4 and IPv6 is compulsory
Group 3
CSE 8343
Advanced OS
Transition Scenarios
IPv4
IPv4
IPv4
IPv4
IPv4
IPv4
IPv4
IPv6
IPv4
IPv6
IPv4
IPv4
IPv4
IPv6
IPv4
IPv4
IPv6
IPv6
IPv6
IPv6
IPv4
IPv6
IPv6
IPv6
IPv6
IPv6
IPv6
IPv4
IPv6
IPv6
CSE 8343
Group 3
Advanced OS
Methods for Interoperability: Dual IP stack
• Scenario A: IPv6 nodes needs to communicate with IPv4 nodes
Solution: Use Dual IP Stacks
• The hosts implement both protocols
• Use IPv4 compatible IPv6 addresses
• Disadvantages:
• Does not addresses the problem of shortage of IP addresses
• Is burdensome for the routers
Solution:
• Network Address Translator - Protocol Translator (NAT-PT)
• Dual Stack Transition Mechanism, or DSTM
CSE 8343
Group 3
Advanced OS
Methods for Interoperability: Tunneling
•
Scenario B: Islands of IPv6 need IPv4 network to communicate
Solution: Use Tunneling
• Append IPv4 header to IPv6 packet
• Route the packet to a host/router having dual
IP stacks
CSE 8343
Group 3
Advanced OS
Methods for Interoperability: Tunneling
Terminology:
• IPv4-only node: A host or router that implements only IPv4
• IPv6/IPv4 node: A host or router that implements both IPv4
and IPv6
• IPv6-only node: A host or router that implements only IPv6
Tunneling can be used in a variety of ways:
• Router-to-Router -- IPv6/IPv4 routers interconnected by
an IPv4 infrastructure can tunnel IPv6 packets between
themselves
• Host-to-Router -- IPv6/IPv4 hosts can tunnel IPv6 packets
to an intermediary IPv6/IPv4 router that is reachable via
an IPv4 infrastructure
• Host-to-Host -- IPv6/IPv4 hosts that are interconnected by
an IPv4 infrastructure can tunnel IPv6 packets between
themselves
• Router-to-Host -- IPv6/IPv4 routers can tunnel IPv6 packets
to their final destination IPv6/IPv4 host
CSE 8343
Group 3
Advanced OS
Methods for Interoperability: Tunneling
Techniques of Tunneling:
• Configured Tunneling
• Used for router-to-router and host-to-router tunneling
• The endpoint of the tunnel is different from the
destination of the packet being tunneled
• The tunnel endpoint address must be determined from
configuration information on the node performing the
tunneling
• Automatic Tunneling
• Used for host-to-host and router-to-host tunneling
• The endpoint of the tunnel is same as the destination
of the packet being tunneled
• IPv4 compatible addresses are used
• IPv6 packets that are not addressed to an IPv4-compatible
address can not be tunneled using automatic tunneling
CSE 8343
Group 3
Advanced OS
Methods for Interoperability: Tunneling
• Disadvantages of Tunneling:
• Not scalable
• Not feasible for dial up users
Solution:
• 6over4
• 6to4
• Tunnel Brokering
Group 3
CSE 8343
Advanced OS
Interoperability Techniques: NAT-PT
• Network Address Translation - Protocol Translation
• Uses a pool of V4 addresses for assignment to V6 nodes
• Requires no change at the end nodes
• Protocol translation is done using SIIT protocol (rfc 2765)
• Maintains session information
A
IPv6
NAT-PT
C
IPv4
B
• How NAT-PT works:
• IPv6 Node A wants to communicate with the IPv4 Node C
• Node A creates a packet as following:
Source Address, SA=FEDC:BA98::7654:3210 and Destination
Address, DA = PREFIX::132.146.243.30
CSE 8343
Group 3
Advanced OS
Interoperability Techniques: NAT-PT
• How NAT-PT works: continued ……
• NAT-PT locally allocates an address (e.g: 120.130.26.10)
from its pool of addresses
• The packet is translated to IPv4
• The translation parameters are cached for the duration
of the session and the IPv6 to IPv4 mapping is retained
by NAT-PT
• Thus resulting IPv4 packet has SA=120.130.26.10 and
DA=132.146.243.30
Disadvantage:
• Pool of V4 addresses assigned for translation purposes is
exhausted
Group 3
CSE 8343
Advanced OS
Interoperability Techniques: DSTM
• Dual Stack Transition Mechanism
• Provides interoperability in an IPv6 dominant network
• Transition mechanism and not a protocol
• Main Components
• DSTM server
• DSTM client
• DSTM border router
DSTM
Server
B
A
IPv6
DSTM
Border Router
IPv4
CSE 8343
Group 3
Advanced OS
Interoperability Techniques: Tunnel Brokering
• Tunnel Brokering
• Allows IPv6 isolated islands to communicate through
IPv4 network
• Ideal choice for small IPv6 site and hosts
• Dedicated servers configure tunnels client’s behalf
• The tunnel broker model has the following components
• Tunnel Broker
• Tunnel Server
• Dual stack Host (user)
Tunnel
Server
User
Tunnel
Broker
Tunnel
Server
Tunnel
Server
CSE 8343
Group 3
Advanced OS
Interoperability Techniques: Tunnel Brokering
• Using the Tunnel Broker
• The Client
• Submits the request to access the services of the
Tunnel Broker
• Provides its IPv4 address
• The Tunnel Broker
• Assigns a Tunnel Server to the client
• Assigns IPv6 global addresses to the tunnel end points
• Assigns a lifetime to the tunnel
• Sends the configuration information to the client
• Tunnel Management
• Lifetime Timer
• Using some sort of keep alive mechanism
• Make the Tunnel Server periodically deliver to the Tunnel
Broker the IPv6 traffic statistics for every active tunnel
CSE 8343
Group 3
Advanced OS
Interoperability Techniques: 6to4
• 6to4
• Allows IPv6 sites to communicate with each other over
the IPv4 network without explicit tunnel setup
• Typically implemented in border routers
• At least one IPv4 address required for the site
• IPv6 domains build their own IPv6 prefix based on the IPv4
address of the border router
• The border router can easily tunnel the packet due to the
use of prefixes
CSE 8343
Group 3
Advanced OS
Other Interoperability Techniques
• 6over4
6over4 is an elegant solution for interconnecting isolated IPv6
hosts in an IPv4 site. IPv6 multicast is implemented over IPv4
multicast. Using IPv6 multicast, IPv6 nodes can then use
Neighbor Discovery to configure themselves.
IPv4 multicast is not generally available on all networks,
and there are scalability issues with this approach.
• Dual Stack ALG
Dual-stack servers are used as proxies to perform protocol
translation with one proxy server per application (http, ftp,
smtp, etc)
Very few IPv4 addresses are required (they are only needed
for the proxies)and
protocol translation step may not be such a large price to pay
in situations where firewalls and proxy server already exist,
which is the case in many LAN
CSE 8343
Group 3
Advanced OS
Questions or Comments