Characterizing VLAN usage in an operational network

Garimella, Prashant; Sung, Yu-Wei Eric; Zhang, Nan; Rao, Sanjay

doi:10.1145/1321753.1321772

Cited by 26 publications

(20 citation statements)

References 9 publications

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“…While we focus on complexity within an ISP's network configuration, prior works [7,15,18,11] have focused on the causes for complexity in enterprises. These studies found core enterprise network designs to be complex due to the usage of VLANs, routeredistribution commands, and network security and filtering policies.…”

Section: Related Workmentioning

confidence: 99%

Demystifying configuration challenges and trade-offs in network-based ISP services

Benson

Shaikh

2011

Proceedings of the ACM SIGCOMM 2011 Conference

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ISPs are increasingly offering a variety of network-based services such as VPN, VPLS, VoIP, Virtual-Wire and DDoS protection. Although both enterprise and residential networks are rapidly adopting these services, there is little systematic work on the design challenges and trade-offs ISPs face in providing them. The goal of our paper is to understand the complexity underlying the layer-3 design of services and to highlight potential factors that hinder their introduction, evolution and management. Using daily snapshots of configuration and device metadata collected from a tier-1 ISP, we examine the logical dependencies and special cases in device configurations for five different network-based services. We find: (1) the design of the core data-plane is usually service-agnostic and simple, but the control-planes for different services become more complex as services evolve; (2) more crucially, the configuration at the service edge inevitably becomes more complex over time, potentially hindering key management issues such as service upgrades and troubleshooting; and (3) there are key service-specific issues that also contribute significantly to the overall design complexity. Thus, the high prevalent complexity could impede the adoption and growth of network-based services. We show initial evidence that some of the complexity can be mitigated systematically.

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Section: Related Workmentioning

confidence: 99%

Demystifying configuration challenges and trade-offs in network-based ISP services

Benson

Shaikh

2011

Proceedings of the ACM SIGCOMM 2011 Conference

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“…VLAN characterization studies. Garimella et al studied VLAN use in a campus network; they highlighted the prevalence of VLANs, characterized different types of misconfiguration, and showed that routing traffic between proximal hosts but distinct VLANs can result in significantly longer layer-3 paths [8]. In contrast, we study the relationships between IP-layer paths and layer-2 paths, and the effects of this sharing on redundancy and diagnosis.…”

Section: Related Workmentioning

confidence: 90%

Characterizing VLAN-induced sharing in a campus network

Tariq

Mansy

Feamster

et al. 2009

Proceedings of the 9th ACM SIGCOMM Conference on Internet Measurement

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Many enterprise, campus, and data-center networks have complex layer-2 virtual LANs ("VLANs") below the IP layer. The interaction between layer-2 and IP topologies in these VLANs introduces hidden dependencies between IP level network and the physical infrastructure that has implications for network management tasks such as planning for capacity or reliability, and for fault diagnosis. This paper characterizes the extent and effect of these dependencies in a large campus network. We first present the design and implementation of EtherTrace, a tool that we make publicly available, which infers the layer-2 topology using data passively collected from Ethernet switches. Using this tool, we infer the layer-2 topology for a large campus network and compare it with the IP topology. We find that almost 70% of layer-2 edges are shared by 10 or more IP edges, and a single layer-2 edge may be shared by as many as 34 different IP edges. This sharing of layer-2 edges and switches among IP paths commonly results from trunking multiple VLANs to the same access router, or from colocation of academic departments that share layer-2 infrastructure, but have logically separate IP subnet and routers. We examine how this sharing affects the accuracy and specificity of fault diagnosis. For example, applying network tomography to the IP topology to diagnose failures caused by layer-2 devices results in only 54% accuracy, compared to 100% accuracy when our tomography algorithm takes input across layers.

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“…A few studies [9,11] examined traffic characteristics in enterprises, and other recent work developed models for design and configuration in enterprises [3,7]. Our work adds to these by shedding light on the nature of reachability policies in enterprises.…”

Section: Related Workmentioning

confidence: 92%

Mining policies from enterprise network configuration

Benson

Maltz

2009

Proceedings of the 9th ACM SIGCOMM Conference on Internet Measurement

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Few studies so far have examined the nature of reachability policies in enterprise networks. A better understanding of reachability policies could both inform future approaches to network design as well as current network configuration mechanisms. In this paper, we introduce the notion of a policy unit, which is an abstract representation of how the policies implemented in a network apply to different network hosts. We develop an approach for reverse-engineering a network's policy units from its router configuration. We apply this approach to the configurations of five productions networks, including three university and two private enterprises. Through our empirical study, we validate that policy units capture useful characteristics of a network's policy. We also obtain insights into the nature of the policies implemented in modern enterprises. For example, we find most hosts in these networks are subject to nearly identical reachability policies at Layer 3.

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Characterizing VLAN usage in an operational network

Cited by 26 publications

References 9 publications

Demystifying configuration challenges and trade-offs in network-based ISP services

Demystifying configuration challenges and trade-offs in network-based ISP services

Characterizing VLAN-induced sharing in a campus network

Mining policies from enterprise network configuration

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