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Large flow detection
The familiar television test pattern is used to measure display resolution, linearity and calibration. Since fast and accurate detection of large flows is a pre-requisite for developing load balancing...
View ArticleBay Area Network Virtualization talk
This talk from a recent Bay Area Network Virtualization Meetup describes how sFlow and OpenFlow can be combined to develop performance aware software defined networking (SDN) applications.Some of the...
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F5 BIG-IP LTM and TMOS 11.4.0
The latest TMOS 11.4.0 release for F5's BIG-IP Local Traffic Manager (LTM) includes comprehensive L2-7 support for sFlow, from packet sampling and interface counters to application response times, URLs...
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Multi-tenant performance isolation
This incident report from an OpenStack based cloud data center illustrates how performance problems can propagate and affect multiple tenants within the data center. This article will examine the...
View ArticleLarge Scale Production Engineering talk
A recent Large Scale Production Engineering (LSPE) meeting included a number of talks looking different aspects of software defined networking (SDN):"Introduction to SDN/Openflow"Xin Huang - Sr....
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Large flow detection script
Large flow detection describes how sFlow monitoring scales to rapidly detect large flows (flows consuming more than 10% of a link's bandwidth). The chart displays the test pattern developed in the...
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Marking large flows
Figure 1: Conceptual view of flow scheduling over a datacenter fabricDeconstructing Datacenter Packet Transport describes how priority marking of packets associated with large flows can improve...
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Top of rack network virtualization
Network virtualization (credit Brad Hedlund)Support for tunneling protocols (NVGRE, VxLAN etc.) and OpenFlow in top of rack switches allows physical hosts to participate in the virtualized network that...
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Visibility and the software defined data center
The emerging software defined data center (SDDC) involves automated control of all network, server, storage and application resources - resulting in a "cloud operating system." Unified visibility is...
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Northbound APIs for traffic engineering
Figure 1:Performance aware software defined networkingPrevious articles on this blog have looked at use cases for performance aware software defined networking, including DDoS mitigation, load...
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Frenetic, Pyretic and Resonance
Northbound APIs for traffic engineering describes some of the limitations with current OpenFlow controllers and describes some of the features needed to support traffic engineering applications....
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RESTful control of switches
Figure 1: Performance aware software defined networking with OpenFlow controllerSoftware defined networking (SDN) controllers typically offer RESTful Northbound APIs to support application developers....
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NSX network gateway services
Figure 1:VMware NSX network gateway services partnersVMware recently released the list of Network Gateway Services (top of rack switch) partners. All but one of these vendors supports the sFlow...
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RESTflow
Figure 1: Embedded, on-switch flow cache with flow record exportThis article describes RESTflow™, a new method for exporting flow records that has significant advantages over current approaches to flow...
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Packet loss
The timeline describes an outage on Sunday, August 25th in Amazon's Elastic Block Store (EBS) service that affected a number of companies, including: Instagram, Vine, Airbnb and Flipboard - see...
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Wile E. Coyote
One of the classic moments in a Road Runner cartoon is Wile E. Coyote pursuing the Road Runner into a cloud of dust. Wile E. Coyote starts to suspect that there is something wrong, but remains...
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Embedding SDN applications
Figure 1:Performance aware software defined networkingPerformance aware software defined networking describes a general architecture for integrating real-time analytics in software defined networking...
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DNS amplification attacks
Figure 1:DNS Amplification Variation Used in Recent DDoS Attacks (Update)DNS Amplification Variation Used in Recent DDoS Attacks (Update) describes how public DNS servers can be used to amplify the...
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ICMP unreachable
Figure 1: ICMP port unreachableFigure 1 provides an example that demonstrates how Internet Control Message Protocol (ICMP) destination port unreachable messages are generated. In the example, host h1...
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UDP packet replication using Open vSwitch
UDP protocols such as sFlow, syslog, NetFlow, IPFIX and SNMP traps, have many advantages for large scale network and system monitoring, see Push vs Pull. In a typical deployment each managed element...
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