MAC Address Research Articles

Improving Ethernet Reliability and Stability Using Global Open Ethernet Technology

In this paper, authors present new schemes of our proposed Global Open Ethernet (GOE) technology from a viewpoint of improving reliability in metro-area Ethernet environment and show the numerical evidence on their performance results. Although several standardized or vendor proprietary technologies are proposed to improve Ethernet reliability, they still have reliability problems in terms of long failure recovery time (due to forwarding database (FDB) flush and recovery from a root bridge failure on spanning tree protocol), broadcast storm, and packet loss in network reconfiguration. To solve these problems, we introduce three schemes, a Per Destination - Multiple Rapid Spanning Tree Protocol (PD-MRSTP), a GOE Virtual Switch Redundancy Protocol (GVSRP), and an In-Service Reconfiguration (ISR) schemes. PD-MRSTP scheme reduces the failure recovery time by eliminating the need to flush the FDB and to recover from root bridge failures. GVSRP scheme ensures the reliability of connections between a GOE domain and a legacy Ethernet domain. Combined with PD-MRSTP, GVSRP prevents broadcast storm problems due to loops in the inter-domain area. ISR scheme enables in-service bridge replacement and upgrade without packet loss. Evaluating our prototype system, we obtained the following remarkable performance results. The GOE network using PD-MRSTP scheme delivered a fast failure recovery performance (4 ms) independent of the number of MAC address entries, whereas the legacy Ethernet network took 522 ms when a bridge had 6000 MAC address entries. Since we found that the failure recovery time increased in proportion to the number of MAC address entries, the one in large carrier network having one million of MAC address entries would take several tens of seconds. Thus using PD-MRSTP can reduce failure recovery time one ten-thousandth comparing with that of legacy Ethernet. In addition, evaluation of the ISR scheme demonstrated that a network can be upgraded with zero packet loss. Therefore, a GOE-based VPN is a promising alternative to other Ethernet VPNs for its reliability and stability.

A duplicate address resolution protocol in mobile ad hoc networks

In an IP-based network, automated dynamic assignment of IP addresses is preferable. In most wired networks, a node relies on a centralized server by using dynamic host configuration protocol (DHCP) to obtain a dynamic IP address. However, the DHCP-based approach cannot be employed in a mobile ad hoc network (MANET) due to the uncertainty of any centralized DHCP server. That is, a MANET may become partitioned due to host mobility. Therefore, there is no guarantee to access a DHCP server. A general approach to address this issue is to allow a mobile host to pick a tentative address randomly, and then use duplicate address resolution (DAR) protocol to resolve any duplicate addresses. In this paper, an innovative distributed dynamic host configuration protocol designed to configure nodes in MANET is presented. The proposed protocol not only can detect the duplicate address, but also can resolve the problem caused by duplicate address. It shows that the proposed protocol works correctly and is more universal than earlier approaches. An enhanced version of DAR scheme is also proposed in this paper to solve the situation of duplicate MAC address. The new and innovative approach proposed in this paper can make the nodes in MANET provide services to other networks and avoid packets from being delivered to incorrect destinations.

Efficient multicasting and broadcasting in layer 2 provider backbone networks

Ethernet has grown from its roots in LANs to contend in previously unchartered territory of MANs and WANs. A slew of projects underway in the IEEE 802 standards bodies plan to groom Ethernet with carrier grade features like high availability, fault management, and resiliency thus far found only in other circuit-switched technologies. These include, among others, IEEE 802.1ag (connectivity fault management), IEEE 802.1ad (provider bridges), and IEEE 802.1ah (provider backbone bridges). IEEE 802.1ah addresses the service and MAC address scalability of provider backbone bridges. Since Ethernet has been architected and designed for a shared medium, it inherently handles broadcast and multicast traffic very efficiently, unlike layer 3 technologies, where multicasting and broadcasting rely on using multiple point-to-point connections. With IEEE 802.1ah, Ethernet would be able to provide millions of service instances in a provider backbone network. While flooding of frames in a LAN may provide for good multicasting, flooding of data in a MAN or WAN could mean huge bandwidth wastages, especially when the remote peers are geographically distant, and the traffic is not necessarily destined to any of its local ports of the peers. In this article we explore technologies to Address efficient multicasting in provider backbone networks. We also consider extending this technology to address unknown unicast floods and efficient proxy of customer multicast frames.

A Virtual MAC Address Scheme for Mobile Ethernet

Heterogeneous wireless access is being integrated into IP networks to support future wireless systems. The enhanced IP technologies being developed must address both handover issues related to mobility management and security issues related to wireless access. We previously proposed a network architecture, Mobile Ethernet, based on wide area Ethernet technologies, that reduces overhead involving handover by managing mobility in the IEEE802 MAC layer. We also proposed a virtual MAC address scheme that introduces a host identifier into layer 2 to accommodate heterogeneous wireless access, manage handover between wireless accesses, provide scalability, and ensure security. In this paper, we design the virtual MAC address scheme for Mobile Ethernet and describe the sequence diagrams of the scheme. We also clarify the effect of our proposed scheme from the viewpoint of scalability by comparing the simulated signaling traffic load at handover with that using FMIPv6.

자율구성 계층구조 애드혹 네트워크를 위한 상호 연동방식의 토폴로지 탐색 및 라우팅 프로토콜

자율구성 계층구조 에드혹 네트워크(Self-organizing hierarchical ad hoc network, SOHAN)는 편평구조 에드혹 네트워크의 확장성을 향상시키기 위해 설계된 새로운 형태, 즉, 액세스 포인트, 전달 노드, 이동 노드의 3 계층의 애드혹 노드로 구성된 네트워크 구조이다. 본 논문에서는 SOHAN의 자율구성을 위한 토폴로지 탐색과 라우팅 프로토콜을 소개한다. 또한 높은 전송 용량을 갖는 최적의 클러스터 기반 계층구조 토폴로지를 형성하기 위한 링크 품질 및 MAC 지연 시간 기반의 크로스레이어 설계방식의 경로 척도를 제안한다. 토폴로지 탐색 프로토콜은 2.5 계층에서 MAC 주소를 기반으로 동작하는 라우팅 프로토콜을 위한 기본적인 정보를 제공한다. 이 라우팅 프로토콜은 AODV 프로토콜을 기반으로 하며, 계층구조의 장점을 활용하기 위해 토폴로지 탐색 프로토콜과 상호 연동하도록 설계된다. 시뮬레이션을 통해 전송용량, 종단간 지연시간, 패킷 전달률, 제어 오버헤드 관점에서 SOHAN의 우수한 성능과 확장성을 보인다. Self-organizing hierarchical ad hoc network (SOHAN) is a new ad-hoc network architecture designed to improve the scalability properties of conventional 'flat' ad hoc networks. This network architecture consists of three tiers of ad-hoc nodes, i.e.. access points, forwarding nodes and mobile nodes. This paper presents a topology discovery and routing protocol for the self-organization of SOHAN. We propose a cross-layer path metric based on link quality and MAC delay which plays a key role in producing an optimal cluster-based hierarchical topology with high throughput capacity. The topology discovery protocol provides the basis for routing which takes place in layer 2.5 using MAC addresses. The routing protocol is based on AODV with appropriate modifications to take advantage of the hierarchical topology and interact with the discovery protocol. Simulation results are presented which show the improved performance as well as scalability properties of SOHAN in terms of through-put capacity, end-to-end delay, packet delivery ratio and control overhead.

Assessment and optimization of schemes for tracking and routing to mobile users in packet-based networks

Although a lot of progress has been made in recent years, supporting mobility in the Internet is still a difficult challenge. The Internet today consists of multiple networks, interconnected by IP routers. In each network multiple subnetworks may coexist, also connected via routers. One subnetwork may connect multiple LAN segments by means of MAC switches. For scalability purposes, IP addresses are hierarchical, which allows routing decisions to be performed using address aggregates. Due to this addressing structure, the IP address of a mobile user needs to change dynamically as the user moves from one subnetwork to another (or one network to another) to match addressing at the new subnet (or the new network). Unlike IP addresses, MAC addresses are flat, as the scale of the problem is smaller. Switches inside a subnetwork track individual users and forward packets to them. If a source sends packets to a destination that is moving and changing IP addresses, the contents of the packet may refer to a destination address that is stale, and the packet may be discarded, or redirected by some special-purpose entity in the network known as an agent. The source may be informed of the change in the IP address of the destination as well, so that future packets can be sent directly to its new location. As users move inside a subnetwork, changes need to take place at one or more switches tracking that user, in an attempt to maintain connectivity to the user at all times. Tracking updates may take a long time to arrive at the agents, end-hosts and switches, which can result in a temporary loss of connectivity to the user. This becomes particularly noticeable when users are engaged in streaming multimedia applications, and may even result in the abortion of TCP sessions. Furthermore, current technologies significantly limit the number of individual addresses that can be tracked by a device built at a reasonable cost. Therefore, any solution to support mobility must deal with inherent delays caused by distances between the moving user and entities in the network that track and assist the user, as well as limitations of the current technology in terms of cost and performance. In this paper we assess, design and optimize schemes to support mobility in the Internet. These schemes exploit techniques called address-lookahead, packet n-casting, transparent learning and light-weight explicit registration. Via numerical simulation, we demonstrate considerable improvements in the user-perceived quality of applications, at no significant increase in cost. For example, 40% more voice calls can experience a high level of quality, at the cost of only a 3% increase in the bandwidth consumption in the Internet.

Distributed on-demand address assignment in wireless sensor networks

Sensor networks consist of autonomous wireless sensor nodes that are networked together in an ad hoc fashion. The tiny nodes are equipped with substantial processing capabilities, enabling them to combine and compress their sensor data. The aim is to limit the amount of network traffic, and as such conserve the nodes' limited battery energy. However, due to the small packet payload, the MAC header is a significant, and energy-costly, overhead. To remedy this, we propose a novel scheme for a MAC address assignment. The two key features which make our approach unique are the exploitation of spatial address reuse and an encoded representation of the addresses in data packets. To assign the addresses, we develop a purely distributed algorithm that relies solely on local message exchanges. Other salient features of our approach are the ability to handle unidirectional links and the excellent scalability of both the assignment algorithm and address representation. In typical scenarios, the MAC overhead is reduced by a factor of three compared to existing approaches.

Authenticated ad hoc routing at the link layer for mobile systems

We have designed an authenticated link-level ad hoc routing protocol and integrated it with the Portland State University implementation of Mobile-IP. The routing protocol addresses link security issues. In our protocol, mobile nodes, as well as agents, broadcast ICMP router discovery packets. The router discovery packets are authenticated and bind the sender's MAC and IP addresses. Problems caused by tying IP subnet schemes to routing on radio links are eliminated. Security problems associated with ARP spoofing are also reduced. This link-level protocol is integrated with Mobile-IP on links where increased security is needed. The protocol replaces ARP, and may be integrated with higher-level multi-hop ad hoc routing protocols.

Group communication security on regional PC communication networks

Security management is an important issue on computer networks with a large number of subscribers. The authors have proposed a regional information network system, which establishes a virtual local area network (LAN) environment for the home users based on the optical subscriber system. A group communication mechanism was proposed, where the subscriber terminals are connected in a loop, so that the access from other subscriber terminals can be prevented without burdening the user by procedures such as address registration. This article shows two implementations for such a group communication, from the side of the subscriber and from the center. The security of each implementation is evaluated, being reduced to physical safety, and the conditions for guaranteeing safety in group communication are derived. It is shown that the safety of group communication is secured by terminal authentication in the regional PC communication network system, basic on the physical composition of the port in the center, containing the multiplexing router, an automatic registration function for the MAC address of the terminal, and the star topology of the optical subscriber system. ? 1999 Scripta Technica, Electron Comm Jpn Pt 1, 83(2): 10–19, 2000

Anatomy of a URL (and other Internet-scale namespaces. 1)

The author discusses the anatomy of a URL (Uniform Resource Locator). He considers domain names, IP addresses, MAC addresses, phone numbers, path names and names in HTTP messages.

MAC address test protocol for a reconfigurable dual‐ring local area network

AbstractThe address of the ring local area network (LAN) station most be unique in the ring. This paper considers the distributed control‐type ring LAN with the configuration management function and proposes an MAC layer address test protocol, which can avoid the duplication of MAC addresses. In the ring LAN, the number of stations contained in the ring is increased or decreased by contraction or expansion of the ring.The duplication of addresses can occur due to the change of the stations, i.e., the set of MAC addresses. Consequently, the proposed system executes the duplicat ed address test being aligned to the ring connection of the station or the ring reconfiguration. the station executes the duplicated address test by the same protocol for various topologies of the ring LAN, such as the single ring, the simple dual ring, and the dual ring with the hierarchical star‐ring structure. By the proposed protocol, it is possible to construct the ring LAN so that the stations have an inherent MAC address no matter how the ring may be reconfigurated.The proposed algorithm is described by the finite‐ state machine (FSM), and a series of processing flows is shown for the address test accompanying the ring reconfiguration. the proposed protocol is included in the IEEE Recommended Practice for the duplicated address test in the dual‐ring LAN with the ring reconfiguration function.

Reducing global address recognition delays in local area networks with spatial bandwidth reuse

Abstract A special class of local area networks have recently received much attention in which destination nodes remove packets from the network, allowing spatial bandwidth reuse or concurrent transmission of packets without collision. Destination removal requires that each node delay packets long enough so it can decode the destination address. If the address is a short label (say, 8-bit) the decoding time is short, but if we want to use global or MAC addresses of 48 or 64 bits, the sum of decoding times encountered by packets may result in unacceptably long delays, even at light traffic loads. In this paper, we propose protocols for reducing global address recognition delays which are designed to supplement existing protocols for local area networks with spatial bandwidth reuse. They are also designed to coexist with other addressing modes used for individual LANs, which are based on the use of very short, locally administered labels. Of particular interest is a completely decentralized protocol which achieves the low global address recognition delays of multi-access protocols and yet seamlessly reverts to efficient spatial bandwidth reuse at high loads. We focus on the MetaRing and MetaNet architectures and apply our methods to these local area networks. A simple probabilistic model is presented which demonstrates significant improvement in delay when our protocols are used.

ATM local area networks

LAN emulation offers a best-effort, connectionless, packet transfer service at the MAC sublayer, implemented on top of a connection-oriented ATM network LAN emulation using switched virtual connections requires address resolution to locate the destination end station followed by connection establishment to the resulting ATM address. Address resolution may be implemented by a broadcast technique or by an address server. The broadcast method is the simplest for small networks but a combination of both is probably better. The use of the MAC address to identify an end station, with dynamic binding to its current physical location in the ATM network, allows the ATM LAN segment to be viewed as a virtual LAN. The virtual LAN model permits end stations to move and change physical location while maintaining connection to the same ATM LAN segment. This greatly simplifies the management of large data networks. >