A survey of advanced ethernet forwarding approaches
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paper_title: Issues and approaches on extending Ethernet beyond LANs

paper_content:

Currently, LAN technology is predominantly Ethernet-based and offers packet-optimized switched technology. With more than 90 percent of Internet traffic originating from Ethernet-based LANs, efforts are underway to extend Ethernet beyond LANs into MANs and further into WANs. However, native Ethernet protocols need extensions or support from other technologies in order to succeed as MAN technology in terms of scalability, QoS, resiliency, OAM, and so on. The two emerging trends to carry Ethernet traffic across the MAN can be classified into native Ethernet (IEEE) protocol extensions, and encapsulation by another transportation technology such as MPLS networks. The goal is to offer new and challenging services such as virtual private LAN service, also known as transparent LAN service (TLS). This article presents a comprehensive overview of the required extensions/support of the Ethernet with an emphasis on the emerging provider bridge technology.
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paper_title: Issues and approaches on extending Ethernet beyond LANs

paper_content:

Currently, LAN technology is predominantly Ethernet-based and offers packet-optimized switched technology. With more than 90 percent of Internet traffic originating from Ethernet-based LANs, efforts are underway to extend Ethernet beyond LANs into MANs and further into WANs. However, native Ethernet protocols need extensions or support from other technologies in order to succeed as MAN technology in terms of scalability, QoS, resiliency, OAM, and so on. The two emerging trends to carry Ethernet traffic across the MAN can be classified into native Ethernet (IEEE) protocol extensions, and encapsulation by another transportation technology such as MPLS networks. The goal is to offer new and challenging services such as virtual private LAN service, also known as transparent LAN service (TLS). This article presents a comprehensive overview of the required extensions/support of the Ethernet with an emphasis on the emerging provider bridge technology.
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paper_title: Multiprotocol Label Switching Architecture

paper_content:

This document specifies the architecture for Multiprotocol Label ::: Switching (MPLS). [STANDARDS-TRACK]
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paper_title: Internet Group Management Protocol, Version 3

paper_content:

This document specifies Version 3 of the Internet Group Management Protocol, IGMPv3. IGMP is the protocol used by IPv4 systems to report their IP multicast group memberships to neighboring multicast routers. Version 3 of IGMP adds support for "source filtering", that is, the ability for a system to report interest in receiving packets *only* from specific source addresses, or from *all but* specific source addresses, sent to a particular multicast address. That information may be used by multicast routing protocols to avoid delivering multicast packets from specific sources to networks where there are no interested receivers.
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paper_title: Virtual Private LAN Service

paper_content:

Hydrogen and oxygen are produced from water in a process involving the photodissociation of molecular bromine with radiant energy at wavelengths within the visible light region and a subsequent electrolytic dissociation of hydrogen halides.
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paper_title: Hierarchical MAC address space in public Ethernet networks

paper_content:

Service providers are showing strong interest in building all-Ethernet public metropolitan networks that would compete with (and eventually replace) the existing network infrastructures based on SONET, Frame Relay, ATM and similar technologies. The main driving factor is the cost, as Ethernet-based technology is typically cheaper than any others available on the market. Despite successful initial laboratory and field deployment tests, there are still many unresolved issues related to metropolitan-scale Ethernet, such as the appropriateness of a spanning tree algorithm, broadcast flooding and MAC address table explosion in core switches. This paper focuses on the problem of MAC address table explosion by introducing a hierarchy into the address space, through Ethernet-inside-Ethernet packet encapsulation. The encapsulation allows core switches to be standard Ethernet switches, while the edge switches implement concepts presented in this paper. The proposed concept is thus transparent to the existing infrastructure and thereby allows building the network using readily available low-cost layer-2 switches.
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paper_title: On Count-to-Infinity Induced Forwarding Loops Ethernet Networks

paper_content:

Ethernet's high performance, low cost and ubiquity have made it the dominant networking technology for many application domains. Unfortunately, its distributed forwarding topology computation protocol - the Rapid Spanning Tree Proto- col (RSTP) - can suffer from a classic "count-to-infinity" problem that may lead to a forwarding loop under certain network failures. The consequences are serious. During the period of "count-to-infinity", which can last tens of seconds even in a small network, the network can become highly congested by packets that persist in cycles in the network, even packet forwarding can fail as the forwarding tables are polluted. In this paper, we explain the origin of this problem in detail and study its behavior. We find that simply tuning RSTP's parameter settings cannot adequately address the fundamental problem with "count-to- infinity". We propose a simple and effective solution called RSTP with Epochs. This approach uses epochs of sequence numbers in protocol messages to eliminate stale protocol information in the network and allows the forwarding topology to recover in merely one round-trip time across the network.
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paper_title: Optimizing QoS aware Ethernet spanning trees

paper_content:

Ethernet is gaining in importance in both access and metro networks. As a layer 2 technology, Ethernet gives a basic framework for routing, QoS and traffic engineering (TE), as well as a protocol for building up trees. IEEE 802.1 standards define default configuration parameters considering the topology only. We propose methods for resource management in Ethernet networks through spanning tree optimization for both STP (spanning-tree protocol) (IEEE 802.1D) and MSTP (multiple spanning-tree protocol) (IEEE 802.1s). As a result of optimization, we assign costs to the bridge ports in the network to build trees based on these costs via STP and MSTP. These trees yield optimized routing, TE and support for different QoS classes. We show on typical metro-access networks that, through optimization, the total network throughput can be significantly increased for both enforcing fairness or allowing starvation of some demands. This gain can be realized by simultaneously assigning demands to trees and routing these trees.
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paper_title: Metro Ethernet traffic engineering based on optimal multiple spanning trees

paper_content:

The flexibility, scalability, simplicity and low cost of Ethernet technology makes it an ideal networking technology for Metro networks. However, the new Ethernet-based solutions must be able to support the growing network needs of the enterprise including the various QoS requirements. Our focus in this paper is traffic engineering which is one of the integral components of QoS provisioning. We propose a scheme based on the generation and management of multiple spanning trees for near optimal traffic distribution.
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paper_title: Traffic engineering in enterprise ethernet with multiple spanning tree regions

paper_content:

IEEE 802.1s multiple spanning tree protocol (MSTP) is part of a family of standards for local and metropolitan area networks based on Ethernet protocol. MSTP allows a set of regions to be defined whose logical union spans the entire network, which in turn defines the association between VLANs and Spanning Tree Instances. In this paper we propose an algorithmic approach for constructing multiple spanning tree regions in the enterprise network domain which will provide better convergence time, reusability of VLAN tags, protection from failures, and optimal broadcast domain size.
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paper_title: Global open ethernet (GOE) system and its performance evaluation

paper_content:

This paper presents an overview of global open Ethernet (GOE) architecture as a cost-effective Ethernet-based virtual private network (VPN) solution, and discusses a hardware and software implementation of a prototype system. Three main approaches have been proposed for a VPN solution on metro-area network: resilient packet ring, Ethernet over multiprotocol label switching (EoMPLS), virtual bridged local area network-tag stacking (Q-in-Q). None of these schemes can satisfy the following requirements at the same time: network topology flexibility, affordable network functionalities, low equipment cost, and low operational cost. The proposed GOE system is designed to solve VPN management problems of these approaches with MPLS VPN functionality at a low cost of Ethernet-based solution. The key components of GOE are: 1) a novel GOE tag for high-speed switching and 2) a novel routing and protection module via per-destination multiple rapid spanning tree protocol (PD-MRSTP). Via the analytical performance evaluation of EoMPLS, Q-in-Q, and GOE, we show that the memory cost and the network utilization of GOE is two-three times smaller and 22% higher than the other approaches, respectively. We also have developed a GOE prototype system and obtained the following remarkable hardware and software performance results. The GOE core switch delivered 100% of theoretical maximum throughput (10 G) with zero packet loss even with the field programmable gate array platform, and its 10-G port density is 1.5 times denser than the best currently available products. The GOE switch using PD-MRSTP also delivered a significantly fast protection switching time (1.975 ms), which was significantly faster than legacy Ethernet switches. These performance evaluation results prove that the proposed GOE system can be used as a cost-effective high-performance Ethernet-based VPN solution.
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paper_title: Alternative multiple spanning tree protocol (AMSTP) for optical Ethernet backbones

paper_content:

The availability and affordable cost of Gigabit and 10 Gigabit Ethernet switches has impacted the deployment of metropolitan area networks (MAN) and campus networks. This paper presents a new protocol, the alternative multiple spanning tree protocol (AMSTP), that uses multiple source based spanning trees for backbones using Ethernet switches. It provides minimum paths and more efficient usage of optical backbone infrastructure than currently proposed protocols such as resilient packet ring and rapid spanning tree. The protocol exhibits features similar to MAC routing protocols like Link State Over MAC (LSOM) such as optimum path and effective infrastructure usage, without requiring MAC routing due to the use of the spanning tree protocol paradigm. AMSTP is not restricted to specific topologies such as ring or tree, but performs efficiently in arbitrary topologies. Among the application areas are optical backbones of campus and MANs.
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paper_title: OSI IS-IS Intra-domain Routing Protocol

paper_content:

This RFC is a republication of ISO DP 10589 as a service to the ::: Internet community. This is not an Internet standard.
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paper_title: Viking: a multi-spanning-tree Ethernet architecture for metropolitan area and cluster networks

paper_content:

Simplicity, cost effectiveness, scalability, and the economies of scale make Ethernet a popular choice for local area networks, as well as for storage area networks and increasingly metropolitan-area networks. These applications of Ethernet elevate it from a LAN technology to a ubiquitous networking technology, thus prompting a rethinking of some of its architectural features. One weakness of existing Ethernet architecture is its use of single spanning tree, which, while useful at avoiding routing loops, leads to low link utilization and long failure recovery time. To apply Ethernet to cluster networks and MANs, these problems need to be addressed. We propose a multi-spanning-tree Ethernet architecture, called Viking, that improves both aggregate throughput and fault tolerance by exploiting standard virtual LAN technology in a novel way. By supporting multiple spanning trees through VLAN, Viking makes the most of the inherent redundancies in most mesh-like networks and delivers a multi-fold throughput gain over single-spanning-tree Ethernet with the same physical network topology. It also provides much faster failure recovery, reducing the down-time to a sub-second range from that of multiple seconds in single-spanning-tree Ethernet architecture. Finally, based only on standard mechanisms, Viking is readily implementable on commodity Ethernet switches without any firmware modifications.
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paper_title: Simple Network Management Protocol (SNMP)

paper_content:

This RFC is a re-release of RFC 1098, with a changed "Status of this ::: Memo" section plus a few minor typographical corrections. This memo ::: defines a simple protocol by which management information for a ::: network element may be inspected or altered by logically remote users. ::: [STANDARDS-TRACK]
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paper_title: SmartBridge: a scalable bridge architecture

paper_content:

As the number of hosts attached to a network increases beyond what can be connected by a single local area network (LAN), forwarding packets between hosts on different LANs becomes an issue. Two common solutions to the forwarding problem are IP routing and spanning tree bridging. IP routing scales well, but imposes the administrative burden of managing subnets and assigning addresses. Spanning tree bridging, in contrast, requires no administration, but often does not perform well in a large network, because too much traffic must detour toward the root of the spanning tree, wasting link bandwidth.
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paper_title: Termination Detection for Diffusing Computations

paper_content:

This invention relates to an electronically rotatable antenna which includes several radially arranged Yagi antennae having a common drive element. Reflector and director elements of each Yagi antenna are sequentially rendered operative by biasing suitable diodes short-circuiting them to a ground-plate. The radiation pattern is step-by-step rotated. Directivity is increased by short-circuiting other elements belonging to other arrays than the main one, those elements defining generatrices of a parabola having the driver element as a focus and the reflector element as an apex.
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paper_title: STAR: a transparent spanning tree bridge protocol with alternate routing

paper_content:

With increasing demand for multimedia applications, local area network (LAN) technologies are rapidly being upgraded to provide support for quality of service (QoS). In a network that consists of an interconnection of multiple LANs via bridges, the QoS of a flow depends on the length of an end-to-end forwarding path. In the IEEE 802.1D standard for bridges, a spanning tree is built among the bridges for loop-free frame forwarding. Albeit simple, this approach does not support all-pair shortest paths. In this paper, we present a novel bridge protocol, the Spanning Tree Alternate Routing (STAR) Bridge Protocol, that attempts to find and forward frames over alternate paths that are provably shorter than their corresponding tree paths. Being backward compatible to IEEE 802.1D, our bridge protocol allows cost-effective performance enhancement of an existing extended LAN by incrementally replacing a few bridges in the extended LAN by the new STAR bridges. We develop a strategy to ascertain bridge locations for maximum performance gain. Our study shows that we can significantly improve the end-to-end performance when deploying our bridge protocol.
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paper_title: Rbridges: transparent routing

paper_content:

This work describes a method of interconnecting links that combines the advantages of bridging and routing. The basic design is a replacement for a transparent bridge and makes no assumption about higher layer protocols. It involves creating an infrastructure of switches (which we call Rbridges, for "routing bridges") in which packets are routed, although, as with bridges, layer 2 end code location is learned through receipt of data packets. It avoids the disadvantages of bridges, since packets within the infrastructure need not be confined to a spanning tree, and packets are protected with a hop count and not proliferated while in transit, so there is no need for any artificial startup delay on ports to avoid temporary loops. This allows IP nodes to travel within a multi-link campus without changing IP addresses. The paper introduces further optimizations for IP, such as avoiding hooding ARP messages through the infrastructure, and (for IP nodes), allowing Rbridges to avoid learning on data packets.
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paper_title: Achieving sub-second IGP convergence in large IP networks

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We describe and analyse in details the various factors that influence the convergence time of intradomain link state routing protocols. This convergence time reflects the time required by a network to react to the failure of a link or a router. To characterise the convergence process, we first use detailed measurements to determine the time required to perform the various operations of a link state protocol on currently deployed routers. We then build a simulation model based on those measurements and use it to study the convergence time in large networks. Our measurements and simulations indicate that sub-second link-state IGP convergence can be easily met on an ISP network without any compromise on stability.
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paper_title: Generalized Multi-Protocol Label Switching (GMPLS) Signaling Functional Description

paper_content:

This document describes extensions to Multi-Protocol Label Switching (MPLS) signaling required to support Generalized MPLS. Generalized MPLS extends the MPLS control plane to encompass time-division (e.g., Synchronous Optical Network and Synchronous Digital Hierarchy, SONET/SDH), wavelength (optical lambdas) and spatial switching (e.g., incoming port or fiber to outgoing port or fiber). This document presents a functional description of the extensions. Protocol specific formats and mechanisms, and technology specific details are specified in separate documents.
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paper_title: Carrier-grade Ethernet for packet core networks

paper_content:

Ethernet is a permanent success story, extending its reach from LAN and metro areas now also into core networks. 100 Gbit/s Ethernet will be the key enabler for a new generation of true end-to-end carrier grade Ethernet networks. This paper first focuses on functionality and standards required to enable carrier-grade Ethernet-based core networks and possible Ethernet backbone network architectures will be discussed. The second part then evaluates the CAPEX and OPEX performance of Ethernet core networks and competitive network architectures. The results propose that Ethernet will not only soon be mature enough for deployment in backbone networks but also provide huge cost advantages to providers. A novel complete, cost-effective and service-oriented infrastructure layer in the area of core networks will arise. The industry-wide efforts to cover remaining challenges also confirm this outlook.
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Title: A Survey of Advanced Ethernet Forwarding Approaches

Section 1: INTRODUCTION
Description 1: This section introduces the recent advances in Ethernet technology and its deployment in large-scale networks. It discusses the limitations of traditional Ethernet in terms of resilience, scalability, and integrated control features, and outlines the scope and organization of the survey.

Section 2: ETHERNET IN THE MAN CORE: METRO ETHERNET NOTIONS AND SERVICES
Description 2: This section provides an overview of Metro Ethernet (ME) notions and services, including a comparison with Asynchronous Transfer Mode (ATM) and a description of the different regions within a Metropolitan Area Network (MAN).

Section 3: Advantages Compared to ATM
Description 3: This section outlines the main advantages of deploying Ethernet in the MAN core compared to ATM, such as better quality/cost trade-off, higher flexibility, less overhead, BRAS decentralization, and true multipoint-to-multipoint connectivity.

Section 4: Challenges
Description 4: This section discusses the challenges Ethernet faces when applied to the MAN core, including issues with reliability, scalability, and the necessity for traffic segregation and control.

Section 5: Services
Description 5: This section covers the conceptual guidelines and standardization approaches for Ethernet services, defining categories such as E-LINE, E-LAN, E-TREE, and discussing the services defined by the IETF for Ethernet transport over Packet Switched Networks (PSNs).

Section 6: Achieving Scalability: Traffic Segregation and Control
Description 6: This section explains the methods used to achieve Ethernet scalability in the MAN, focusing on traffic segregation through tagging and encapsulation schemes, and techniques to control multicast traffic.

Section 7: IEEE SPANNING-TREE APPROACHES
Description 7: This section provides an overview of current IEEE spanning-tree standards, including STP, RSTP, and MSTP, and highlights their differences and evolution.

Section 8: NOVEL SPANNING-TREE BASED APPROACHES
Description 8: This section describes advanced Ethernet approaches that build upon spanning-tree protocols, such as Global Open Ethernet (GOE), Alternative Multiple Spanning Tree Protocol (AMSTP), and other novel solutions to improve convergence and resilience.

Section 9: ALTERNATIVE ETHERNET FORWARDING APPROACHES
Description 9: This section examines approaches that enhance Ethernet forwarding by departing from traditional spanning-tree protocols, focusing on methods that support shortest-path and multiple-path routing while maintaining the connectionless nature of Ethernet.

Section 10: CONNECTION-ORIENTED ETHERNET APPROACHES
Description 10: This section explores approaches that build carrier-grade Ethernet services by establishing connection-oriented tunneling and traffic engineering solutions, detailing methods such as PBB-TE, VLAN Cross-Connect (VXC), and T-MPLS.

Section 11: SUMMARY AND CONCLUSIONS
Description 11: This section summarizes the findings of the survey, discussing the potential and limitations of both connectionless and connection-oriented Ethernet approaches for large-scale network deployments, and concludes with insights on the future direction of Ethernet forwarding technologies.