Network Address Research Articles

A Survey of NAT Behavior Discovery in VoIP Applications

Because of the foreseeing depletion of Internet Protocol (IP) addresses, Network Address Translation (NAT) is ubiquitously deployed to allow hosts to connect to the Internet through a single shared public IP address, which is a popular approach in deploying wireless local area network (WLAN). Although NAT proves to work well with traditional client/server applications, its existence and non-standard behaviors are the major problem which cripples voice over IP (VoIP) applications. In addition to some efforts which attempt to devise complicated protocols to tackle all NAT varieties, there are also efforts in Internet communities trying to standardize the behaviors of NAT. Therefore, it becomes crucial for a network device to discover the existence of NAT in its subnet and to determine the NAT behaviors, so that it can choose the optimal NAT traversal mechanisms to apply. In this paper, we surveyed the divergent NAT behaviors and then proposed a simplified NAT behavior discovery approach which is more suitable for VoIP applications. The proposed approach can reduce the call establishment time of VoIP applications, which is useful in scenarios where VoIP devices are administrated within a specific domain, e.g., 3G cellular networks.

Potential Impacts on Communications from IPv4 Exhaustion & IPv6 Transition

The Internet is in transition. The original address space, IPv4, is nearly exhausted; the Internet is in the progress of migrating to the new IPv6 address space. The Internet Protocol version 4 (IPv4) developed in the late 1970s has the capacity for about 4 billion unique addresses. It would have been hard to imagine in the 1970s that 4 billion addresses were not going to be enough. But by the early 1990s, Internet engineers recognized that the supply of addresses was relatively limited compared to likely demand, and they set to work designing a successor to IPv4. They developed a new Internet Protocol, IPv6, with a vastly increased address space: 340 trillion trillion trillion addresses. Broadband Internet access has become essential to the United States and the rest of the world. The exhaustion of IPv4 addresses and the transition to IPv6 could result in significant, but not insurmountable, problems for broadband Internet services. In the short term, to permit the network to continue to grow, engineers have developed a series of kludges. These kludges include more efficient use of the IPv4 address resource, conservation, and the sharing of IPv4 addresses through the use of Network Address Translation (NAT). While these provide partial mitigation for IPv4 exhaustion, they are not a long-term solution, increase network costs, and merely postpone some of the consequences of address exhaustion without solving the underlying problem. Some of these fixes break end-to-end connectivity, impairing innovation and hampering applications, degrading network performance, and resulting in an inferior version of the Internet. These kludges require capital investment and ongoing operational costs by network service providers, diverting investment from other business objectives. Network operators will be confronted with increased costs to offer potentially inferior service. The short term solutions are necessary because there is not enough time to completely migrate the entire public Internet to native IPv6 where end users can communicate entirely via IPv6. Network protocol transitions require significant work and investment, and with the exhaustion of IPv4 addresses looming, there is insufficient time to complete the full IPv6 transition. But the short-term solutions are problematic. The solution to the solution is to complete the transition to a native IPv6 network. A native IPv6 network will restore end-to-end connectivity with a vastly expanded address space, will improve network performance, and should decrease costs. Completing the transition of the public Internet to IPv6 will take time.

User-perceived reliability of shared protection systems with the Erlang type-k repair scheme

This paper describes the availability and mean time to first failure (MTTFF) of M-for-N shared protection systems (with M + N units) from the viewpoint of an arbitrary one of the N end users. Various forms of M-for-N shared protection are used to improve the reliability of telecommunication network devices such as access node devices, routers, switches, servers, network address translators, etc. In this paper, the time between failures of units and the time for repair are assumed to be an exponential distribution and the Erlang type-k distribution respectively. We consider the Erlang type-k distribution because repair time does not necessarily follow the exponential distribution and the Erlang type-k distribution is more flexible and useful for determining the system parameters such as the mean repair time and the variance based on the reliability objectives. The purpose of this paper is to evaluate the user-perceived reliability of such systems in a quantitative manner.

An Improved Algorithm About Failure Agreement Based on Distributed Shared Memory

According to the uniform addressing and direct localization of network address space, adopting multi-threaded, multi-copy store and block storage in pages, page tree sub-node parallel failure methods, these can improve the efficiency and parallel processing of the DSM system. It is significance for improving the performance of distributed systems.

Practical Evaluation of Stateful NAT64/DNS64 Translation

It is often suggested that the approach to IPv6 transition is dual-stack deployment; however, it is not feasible in certain environments. As Network Address Translation -- Protocol Tra ...

To Call or To Be Called Behind NATs is Sensitive in Solving the Direct Connection Problem

In this article, we first depict the call-role sensitivity problem in Network Address Translation (NAT) traversal, and then propose an approach to resolving the problem. The problem is whether a direct connection can be found between two peers across NATs mainly depends on the NAT type at the caller's side. We propose the extra-candidate connectivity check where both peers initiate a direct connectivity check to eliminate the effect of the call role. We have implemented the extra-candidate connectivity check and conducted experiments with 18 different NATs. Experimental results show that our approach can indeed resolve the call-role sensitivity problem, and maximize the direct connectivity rate (DCR) which is improved by 18.71% from the original scheme.

Extended UDP Multiple Hole Punching Method to Traverse Large Scale NATs

A Network Address Translator (NAT) is a popular technological tool used in networks, especially in small-sized networks. Recently, network operators have been considering deploying Large Scale NATs (LSNs) to cope with IPv4 address pool exhaustion. This will make it necessary to deal with several problems related to LSNs, such as multiple levels of NATs (cascaded NATs) and the shortage of port numbers used by NATs. To address these issues, this paper extends the concept of UDP Multiple Hole Punching previously proposed by us. The use of our proposed method enables an accurate Port Prediction and reduces the number of open ports. The new method can determine the low TTL values for IP packets. We also discuss the application of i-Path routers, which provide status information about NATs along a network path for end hosts. The use of these routers makes it easier to perform NAT traversal.

Network Security Alerts Management Architecture for Signature-Based Intrusions Detection Systems within a NAT Environment

Internet is providing essential communication between an infinite number of people and is being increasingly used as a tool for commerce. At the same time, security is becoming a tremendously important issue to deal with. Different network security solutions exist and contribute to enhanced security. From these solutions, Intrusion detection systems (IDS) have become one of the most common countermeasures for monitoring safety in computer systems and networks. The purpose of IDSs is distinguishing between intruders and normal users. However, IDSs report a massive number of isolated alerts. These isolated alerts represent low-level security-related events. Many of these isolated alerts are logically involved in a single multi-stage intrusion incident and a security officer often wants to analyze the complete incident instead of each individual simple alert. Another problem is that IDSs cannot work correctly with an environment managed with a NAT technique (Network Address Translation) since the host information (IP address and port number) are affected by the NAT devices. In order to address these limitations, the paper proposes a well-structured model to manage the massive number of isolated alerts and includes the NAT information in the IDS analysis. In fact, our solution permits to determine the real identities of entities implicated in security issues and abstracts the logical relation between alerts in order to support automatic correlation of those alerts involved in the same intrusion and to construct comprehensible attacks scenarios.

Design and analysis of new generation protocols for triple-play networks

Abstract Transmission Control Protocol (TCP)'s proven stability and scalability has made it the most widely used transport layer protocol for more than twenty years. However, as multimedia applications become ubiquitous over the internet, TCP has been found incapable of meeting their requirements, which place more emphasis on timeliness than on reliability. Because of that, many multimedia applications turn to UDP as their underlying transport protocol. However, the majority of video on demand and live broadcast applications predominantly use TCP over UDP (User Datagram Protocol), due to UDP's unresponsiveness to network conditions and problems with firewalls and NATs (Network Address Translations). TCP's poor performance in delivering real-time media is due to the following reasons: 1) TCP's emphasis on reliable in-order delivery causes frame jitter that interrupt media play out. 2) TCP's coarse-grained retransmission timeout (RTO) and its back-off mechanism is detrimental to any real-time based application. In this study, we propose a new variant of TCP with an early retransmission scheme as an enhancement to make it more suitable for streaming media. We call this new protocol TCP-ER. We performed extensive NS-2 simulations to show that: 1) the early retransmission scheme can reduce the number of retransmission timeouts in a variety of network environments, which results in a considerable decrease in number of retransmission timeouts and packet delay jitter. 2) Under same network conditions, constrained streaming over TCP-ER has a considerably lower number of late packets than its normal TCP counterpart. 3) TCP-ER has a higher throughput in severely congested network conditions, whereas it stays relatively fair with typical TCP implementations (specifically TCP-SACK) as congestion gets alleviated.

이동 에이전트를 이용한 유무선 네트워크의 통합관리 기법

중앙 집중적 네트워크 관리 구조인 SNMP(Simple Network Management Protocol)를 무선 네트워크 관리에 적용하면 네트워크 과부하, AP에서의 NAT(Network Address Translation)로 인한 관리의 문제, 그리고 무선 노드의 성능 저하가 발생한다. 본 연구에서는 이러한 문제를 해결하기 위해 MA(Mobile Agent)를 도입한 유무선 네트워크 통합 관리 기법을 제안한다. 제안기법에서 유선 네트워크는 SNMP 기반으로 관리하고 무선 네트워크는 AP 또는 무선 노드에 SNMP를 MA 기반으로 구현하여 관리한다. 또한, SNMP 응답 메시지 내에 중복되는 OID 정보를 줄이는 방법도 제시한다. 분석을 통해 제안 기법이 제시된 문제를 해결하고 무선 노드에 대한 처리 시간이 개선됨을 보인다. Appling centralized network management architecture SNMP(Simple Network Management Protocol) to wireless networks causes the network overhead, NAT(Network Address Translation) problem on AP, and performance degradation of mobile nodes. In this paper, we propose an integrated management scheme for wired and wireless networks using mobile agents in order to solve above problems. In our proposed scheme, SNMP is applied to manage wired networks and MAs of SNMP are implemented in APs or wireless nodes to manage wireless networks. In addition, we propose a method to reduce the redundant OID information within SNMP response messages. Through the analysis, we show that our proposal resolves the given problems and reduces the processing delay of the wireless nodes.

System Virtualization and Efficient ID Transmission Method for RFID Tag Infrastructure Network

The use of RFID tag which identifies a thing and an object will be expanded with progress of ubiquitous society, and it is necessary to study how to construct RFID network system as a social infrastructure like the Internet. First, this paper proposes the virtualization method of RFID tag network system to enable the same physical RFID network system to be used by multiple different service systems. The system virtualization not only reduces the system cost but also can dramatically reduce the installation space of physical readers and the operation cost. It is proposed that all equipments in the RFID network system except RFID tag could be shared with the conventional virtual technologies. Then, this paper proposes the conditional tag ID processing and the efficient tag ID transmission method which can greatly reduce the processing time and processing load in RFID tag Infrastructure network The conditional tag ID processing allows that tag ID is valid only at a certain time zone of day or in a certain area. The efficient tag ID transmission method uses the virtual network address of the service center as a part of the ID of an RF tag, which allows the direct ID forwarding to the service center.

Security Concerns in IPv6 and Transition Networks

ABSTRACT This whitepaper introduces the concept of a transitional network, defines what it is, how it is used and why a transitional network is necessary. A brief history of IPv6 is given followed by a review of the known vulnerabilities associated with the IPv6 protocol. Popular transition strategies are explored in greater detail around issues of cost, implementation and security vulnerabilities. Mitigation techniques and counter-measures are reviewed against known exploits for each of the transition mechanisms. The last section offers an in depth investigation into the IPv6 mobility protocol, Network Address Translation - Protocol Translation (NAT-PT) and tunneling options.

A Novel Data-Oriented Name Service

The Internet has evolved from its original design. (1)The user cares about what they are looking for, not which machine provides the data or the service. The host-to-host Internet tends to become a data-oriented network. (2) In the pressures of commerce and security, the middleboxes, such as network address translators (NATs), firewalls and caching servers, become commonplace in current Internet. They improve the performance of the applications and security, but also violate the Internet layering and are difficult to maintain and configure. To adapt these changes, we proposed the novel Data-Oriented Name Service (DONS), which gives a clean-slate redesign of Internet naming and name resolution. It achieves (1) permanence, getting the resource using the persistent name; (2) semantic-free, improving the flexibility and functionality of the network; (3) middlebox integration, allowing and facilitating the deployment of middleboxes; (4) self-certifying, authenticating the source.

The Delay-Friendliness of TCP for Real-Time Traffic

TCP has traditionally been considered inappropriate for real-time applications. Nonetheless, popular applications such as Skype use TCP since UDP packets cannot pass through restrictive network address translators (NATs) and firewalls. Motivated by this observation, we study the delay performance of TCP for real-time media flows. We develop an analytical performance model for the delay of TCP. We use extensive experiments to validate the model and to evaluate the impact of various TCP mechanisms on its delay performance. Based on our results, we derive the working region for VoIP and live video streaming applications and provide guidelines for delay-friendly TCP settings. Our research indicates that simple application-level schemes, such as packet splitting and parallel connections, can reduce the delay of real-time TCP flows by as much as 30% and 90%, respectively.

Understanding block-level address usage in the visible internet

Although the Internet is widely used today, we have little information about the edge of the network. Decentralized management, firewalls, and sensitivity to probing prevent easy answers and make measurement difficult. Building on frequent ICMP probing of 1% of the Internet address space, we develop clustering and analysis methods to estimate how Internet addresses are used. We show that adjacent addresses often have similar characteristics and are used for similar purposes (61% of addresses we probe are consistent blocks of 64 neighbours or more). We then apply this block-level clustering to provide data to explore several open questions in how networks are managed. First, we provide information about how effectively network address blocks appear to be used, finding that a significant number of blocks are only lightly used (most addresses in about one-fifth of 24 blocks are in use less than 10% of the time), an important issue as the IPv4 address space nears full allocation. Second, we provide new measurements about dynamically managed address space, showing nearly 40% of 24 blocks appear to be dynamically allocated, and dynamic addressing is most widely used in countries more recent to the Internet (more than 80% in China, while less than 30% in the U.S.). Third, we distinguish blocks with low-bitrate last-hops and show that such blocks are often underutilized.

Modeling and analysis of Internet worm propagation

Although the frequency of Internet worm's outbreak is decreased during the past ten years, the impact of worm on people's privacy security and enterprise's efficiency is still a severe problem, especially the emergence of botnet. It is urgent to do more research about worm's propagation model and security defense. The well-known worm models, such as simple epidemic model (SEM) and two-factor model (TFM), take all the computers on the internet as the same, which is not accurate because of the existence of network address translation (NAT). In this paper, we first analyze the worm's functional structure, and then we propose a three layer worm model named three layres worm model (TLWM), which is an extension of SEM and TFM under NAT environment. We model the TLWM by using deterministic method as it is used in the TFM. The simulation results show that the number of NAT used on the Internet has effects on worm propagation, and the more the NAT used, the slower the worm spreads. So, the extensive use of NAT on the Internet can restrain the worm spread to some extent.

Network Address Translation: Extending the Internet Address Space

Network Address Translation (NAT) and Network Address and Port Translation (NAPT) are widely used to separate networks and share IPv4 addresses. They're valuable tools for network administrators and help with the imminent exhaustion of IPv4 address space and the transition to IPv6. This article surveys recent standardization efforts in this area.

Research on network address mapping algorithm in IPv6 private network

Internet protocol version 6 (IPv6)-to-IPv6 network address translation (NAT66) is a new technology, which is proposed to provide the address independence benefit associated with IPv4-to-IPv4 NAT (NAT44) while minimizing the problems. Some corporate network managers may deploy NAT66 in their internal IPv6 network to hide their topology, to utilize multi-homing and so on. This paper introduces the checksum-neutral two-way network address mapping algorithm used in ANT66 to solve the problem of network translation from an IPv6 address to another in global systems engineering (GSE) mode and implements it both in a Linux host and a customer-provided equipment (CPE) router with netfilter/iptables. Meanwhile, this paper gives the experimental results in IPv6 network to show the performance.

Optimizing BitTorrent-like peer-to-peer systems in the presence of network address translation devices

BitTorrent nowadays is one of the most important peer-to-peer (P2P) file-sharing applications on the Internet, and it has also inspired many other P2P applications such as live or on-demand video streaming services. On the other hand, Network Address Translation (NAT) has become pervasive in almost all networking scenarios, from residential Internet access to enterprise networks. Despite the effort of NAT traversal, it is still very likely that P2P applications cannot receive incoming connection requests properly if they are behind NAT. To quantify the performance impact of NAT on BitTorrent-like P2P systems, we have created and validated a detailed but tractable mathematical model. We have also proposed and briefly examined a simple but effective strategy to mitigate the negative impact on NAT peers. In this paper, we further extend our model to cover the proposed biased optimistic unchoke strategy, and optimize the system performance in terms of both average peer download time and system finish time. We also create a new, faster Java-based BitTorrent simulator, which is used to validate the extended model and show the optimality of the proposed strategy and its boundary conditions.

A collaborative P2P scheme for NAT Traversal Server discovery based on topological information

In the current Internet picture more than 70% of the hosts are located behind Network Address Translators (NATs). This is not a problem for the client/server paradigm. However, the Internet has evolved, and nowadays the largest portion of the traffic is due to peer-to-peer (p2p) applications. This scenario presents an important challenge: two hosts behind NATs (NATed hosts) cannot establish direct communications. The easiest way to solve this problem is by using a third entity, called Relay, that forwards the traffic between the NATed hosts. Although many efforts have been devoted to avoid the use of Relays, they are still needed in many situations. Hence, the selection of a suitable Relay becomes critical to many p2p applications. In this paper, we propose the Gradual Proximity Algorithm (GPA): a simple algorithm that guarantees the selection of a topologically close-by Relay. We present a measurement-based analysis, showing that the GPA minimizes both the delay of the relayed communication and the transit traffic generated by the Relay, being a QoS-aware and ISP-friendly solution. Furthermore, the paper presents the Peer-to-Peer NAT Traversal Architecture (P2P-NTA), which is a global, distributed and collaborative solution, based on the GPA. This architecture addresses the Relay discovery/selection problem. We have performed large-scale simulations based on real measurements, which validate our proposal. The results demonstrate that the P2P-NTA performs similarly to direct communications with reasonably large deployments of p2p applications. In fact, only 5% of the communications experience an extra delay that may degrade the QoS due to the use of Relays. Furthermore, the amount of extra transit traffic generated is only 6%. We also show that the P2P-NTA largely outperforms other proposals, where the QoS degradation affects up to more than 50% of the communications, and the extra traffic generated goes beyond 80%.