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 Advanced OS 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

CSE 8343 Group 3 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

CSE 8343 Group 3 Advanced OS Transition Scenarios IPv4 IPv4 IPv4 IPv4 IPv4 IPv4 IPv6 IPv4 IPv6 IPv4 IPv4 IPv4 IPv6 IPv4 IPv6 IPv4 IPv6 IPv4 IPv6 IPv6 IPv6 IPv4 IPv6 IPv4 IPv6 IPv6 IPv6 IPv6 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 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 Methods for Interoperability: Tunneling

CSE 8343 Group 3 Advanced OS 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 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 Methods for Interoperability: Tunneling

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

Disadvantages of Tunneling: Not scalable Not feasible for dial up users Solution: 6over4 6to4 Tunnel Brokering Methods for Interoperability: Tunneling CSE 8343 Group 3 Advanced OS

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 Interoperability Techniques: NAT-PT CSE 8343 Group 3 Advanced OS C B A NAT-PT IPv6 IPv4 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::

How NAT-PT works: continued …… NAT-PT locally allocates an address (e.g: ) 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= and DA= Interoperability Techniques: NAT-PT CSE 8343 Group 3 Advanced OS Disadvantage: Pool of V4 addresses assigned for translation purposes is exhausted

Interoperability Techniques: DSTM CSE 8343 Group 3 Advanced OS 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 A B DSTM Server IPv6 IPv4 DSTM Border Router

Interoperability Techniques: Tunnel Brokering CSE 8343 Group 3 Advanced OS 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) User Tunnel Broker Tunnel Server Tunnel Server Tunnel Server

Interoperability Techniques: Tunnel Brokering CSE 8343 Group 3 Advanced OS 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

Interoperability Techniques: 6to4 CSE 8343 Group 3 Advanced OS 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

Other Interoperability Techniques CSE 8343 Group 3 Advanced OS 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