Application of Mobile IPv6 in Wireless Networks (1)

How should we set wireless network technology? How does IPV6 affect wireless networks? The following articles unveil the mysteries of us.

1. Introduction

3G network operators hope to provide a large number of application services for potential customers, including traditional voice services and unimaginable services. 3G networks can handle a large amount of traffic needs, which may lead to the implementation of mobile Internet.

Currently, the protocol used in the Internet is TCP/IP, which is very effective and successful in handling burst, asymmetric, and unpredictable data. Therefore, IP addresses will play an important role in 3G networks in the future, that is, the so-called full IP network. This is an indisputable fact. However, IP addresses still have some problems in 3G networks. For example, IP addresses do not support real-time QoS, and multimedia data in 3G networks must be supported in real time, these need to be done by other protocols. In addition, IP addresses cannot be moved between cells during data transmission.

Although IPv4 is still the main IP version in many fixed networks, some network operators have begun to consider using IPv6 in their network architecture, and 3GPP has used IPv6 as a standard protocol in 3G networks.

2. IP addresses in 3G networks

For economic reasons, network operators generally choose the IP protocol, because IP addresses are everywhere. From the perspective of engineering technology, the IP address structure is simple, which can be used for both fixed networks and mobile networks for ease of implementation and management. From the perspective of end users, what they need is that when accessing data, data integrity and consistency are ensured, and these IP addresses can also be completed. However, in 3G networks, IP addresses have special requirements:

* Data Transmission

* Data Exchange in circuit switching and Packet Switching Networks

3. All IP addresses

The 3GPP standard introduces a full IP network, but what is the network of this full IP address. People have different opinions on this. Some people think it is an end-to-end local IP solution, while others think it only involves the core network. Aside from these details, I think we can divide the network into three parts for discussion. These three parts include:

* Core network

* Wireless Network

* Wireless interface

3.1 advanced requirements for all IP Networks

3G network operators need to deal with two basic communication domains: Circuit Switching Network and packet switching network. Combining the two into one will lead to a more complex network. Some basic advanced requirements for a full IP network include:

* The end-to-end QoS of voice and other real-time data must at least reach the circuit switching network level.

* Call Control and telephone services, such as call transfer and caller identity.

* Mobility support

* Effective use of wireless spectrum

3.2 voice and real-time services

Voice Service is a basic network service provided by 3G. However, voice services have special quality requirements. For example, in the PSTN, voice has strict requirements on latency, ECHO, and definition. In VoIP, there will also be other factors that affect the voice, such as the latency caused by jitter and the definition Attenuation Caused by packet loss, as well as bandwidth restrictions and data compression. During voice and real-time data transmission, the late package is the lost package. Speech QoS relies on end-to-end performance, which means that each entity in the network must be allocated with sufficient resources. Currently, due to the use of resources such as RSVP (Resource Reservation Protocol) such a protocol or a stream classification scheme such as MPLS (multi-protocol stream tag switching) requires streaming management. If the operator can manage all the networks, these mechanisms can run well, but in fact they cannot.

However, if IPv6 is used, the situation may change. A flow tag domain is defined in IPv6, which can be used by RSVP. There is a filter in the RSVP information, which can be used to define the data type for transmission. For example, when an application needs to transmit a file or voice stream, a filter can be used to define a TCP port for file transmission and a UDP port for voice transmission. In IPv6, the header can be hidden behind many Control headers, so the receiver does not need to define the port, but can use the stream tag.

One noteworthy problem is that TCP was originally used for fixed networks for reliable transmission. However, it may not be suitable for wireless networks. Because wireless networks have higher error rates, which include signal attenuation, signal transfer from base stations, and load. In TCP, packet loss is considered a result of a network conflict, rather than a data bit transmission problem. If no correction is made, only TCP is used, therefore, a large number of packets in wireless networks will be considered as missing. Therefore, the efficiency of TCP is not high in wireless networks.

In addition to the stream marking domain, IPv6 also defines a priority domain, which can control the packet sending sequence. If priority is greater than 8, data with strict time requirements is obtained. Priority ranges from 0 ~ 7 is the data that can withstand latency. This domain facilitates QoS Management for 3G networks.