Soft Examination Chapter 7 Next Generation Internet

next generation internet

1.IPv6

Defects of IPv4:

• Shortage of network addresses
• The routing speed is slow, the IPv4 header has as many as 13 fields, and the router processes a large amount of information
• lack of security features
• Does not support new business models

The research results on PIv6 are included in the RFC 2460 document published in December 1998

1.1 IPv6 packet format

• Version: Use 0110 to indicate IP version 6
• Communication type: used to distinguish different IP groups, which is equivalent to the service type field in IPv4.
• Flow mark: The original host uses this field to identify some packets that need special processing, such as special quality of service or real-time data transmission.
• Payload length: Indicates the payload length except the IPv6 fixed header 40 bytes, and the extension header is included in the payload length
• Next header: Indicates the type of the next header, which may be an IPv6 extension header or a higher-level protocol header
• Hop Limit: Used to detect routing loops
• source address
• target address

1.2 IPv6 address

An IPv6 address is an identifier for an interface or a group of interfaces, and IPv6 is assigned to interfaces , not to nodes . (A node may have multiple interfaces and thus multiple IPv6 addresses)

There are 3 types of IPv6 addresses:

• Unicast address: For nodes with multiple interfaces, a certain length of format prefixes are aggregated to form a unicast address

• Anycast address: an identifier representing a group of interfaces (which can belong to different nodes), can only be used as a target address, and can only be assigned to a router

• Multicast address: is the identifier of a group of interfaces (generally belonging to different nodes)

IPv6 address configuration:

• Stateful auto-configuration: DHCP service inherited from IPv4
• Stateless automatic configuration: First, the host appends the MAC address of its network card to the link-local address prefix 1111 1110 10 to generate a link-local address, and sends an ICMPv6 neighbor discovery request to verify the uniqueness of its address. Indicates unique if the request has no response. Otherwise, the host will use a randomly generated interface ID to form a new link-local address. After obtaining the link-local address, the host uses the address as the source address to send a multicast ICMPv6 router request message to all routers on the local link, and the router responds with a router advertisement message containing an aggregatable global unicast address prefix . The host uses the address prefix + its own interface ID to automatically configure a global unicast address.

1.3 IPv6 Routing Protocol

1. RIPng: Modifications to RIPv2:
   • UDP port number: use port 521
   • Multicast address: Use FF02::9 as the multicast address for RIPng routers in link-local scope
   • Routing prefix: use 128-bit IPv6 as routing prefix
   • Next Hop: 128 bits
2. OSPFv3
3. BGP4+
4. ICMPv6: Newly added the neighbor discovery function to replace the ARP protocol function, so there is no ARP protocol in the IPv6 system

2. Mobile IP

2.1 Communication Process of Mobile IP

Each mobile host is configured with a home address (home address) as a permanent identifier. When the mobile host leaves the home network, it is given a care-of address by the foreign agent at the location. The protocol provides a registration mechanism, so that the mobile host can obtain the care-of address through the home address. The home agent can forward the packet to the foreign agent through a secure tunnel, and then be submitted to the mobile host.

There is a home agent (home agent) process in each LAN, and their task is to track mobile hosts that belong to the local network but are connected to the Internet in other places. At the same time, there is also a foreign agent process, whose task is to monitor all mobile hosts that visit in different places. When a mobile host enters a site, it must register with a nearby foreign agent. Upon registration, a care-of address is assigned.

If another host sends information to the mobile host, the communication process:

1. The first packet is sent to the home address
2. The first packet is tunneled to the mobile host's care-of address
3. The home agent returns the sending node to the foreign agent's care-of address
4. The sending node tunnels subsequent packets to the care-of address of the mobile host

The care-of address is the end point of the tunnel, which may be the address of the foreign agent, or it may be a temporary address obtained by the mobile host (in this way, it can also work in networks without foreign agents).

2.2 Mobile IPv6

optimization:

• Simplifies the process of assigning the care-of address
• Usually only the first packet sent by the peer node is forwarded by the home agent. When the mobile node sends the "binding update" message to the home agent, other subsequent packets will be transmitted through the routing header, reducing the communication overhead of the network. .
• No foreign agent required

3. Transition from IPv4 to IPv6

3.1 Tunnel technology

• Tunnel Intermediary Technology
• automatic tunnel
• 6to4 tunnel: support IPv6 sites to communicate through IPv4 network
• 6over4: Generate an IPv6 link-local address from an IPv4 address
• ISATAP: automatic tunneling technology, which can penetrate NAT devices and establish IPv6 connections with hosts outside the private network

3.2 Protocol Translation Technology

Protocol translation technology used for communication between pure IPv6 hosts and pure IPv4 hosts

• SIIT: Stateless IP/ICMP Translation
• NAT-PT: Network Address Translation-Protocol Translation
• SOCKS64
• TRT

3.3 Dual protocol stack technology

It is suitable for communication between hosts that realize both IPv4 and v6 protocol stacks. In this case, use the appropriate protocol for the situation to communicate

• BIS
• BIA