We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. However, you may visit "Cookie Settings" to provide a controlled consent. Cookie Settings Accept All. Manage consent. Close Privacy Overview This website uses cookies to improve your experience while you navigate through the website. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website.
We also use third-party cookies that help us analyze and understand how you use this website. These cookies will be stored in your browser only with your consent. You also have the option to opt-out of these cookies. But opting out of some of these cookies may affect your browsing experience.
Necessary Necessary. Functional Functional. Performance Performance. Analytics Analytics. Advertisement Advertisement. Others Others. VPLS does not natively address this risk, so storm control mechanisms must be deployed. VPLS is often used by service providers to provide Ethernet Multipoint Services EMS and is also being adopted by Enterprises on a self-managed MPLS-based metropolitan area network MAN to provide high-speed any-to-any forwarding at Layer 2 without the need to rely on spanning tree to keep the physical topology loop free.
The MPLS core uses a full mesh of pseudowires and split-horizon to avoid loops. If the destination address is unknown, or is a broadcast or multicast address, the frame is flooded to all ports associated with the virtual bridge. Compared to traditional LAN switching technologies, VPLS is also more flexible in its geographic scaling, so that Customer Edge CE sites may be within the same metropolitan domain, or may be geographically dispersed on a regional or national basis.
The increasing availability of Ethernet-based multipoint service architectures from service providers, for both L2 VPN and L3 VPN services, is resulting in a growing number of enterprises transitioning their WANs to these multipoint services and VPLS is playing an increasingly important role in this transition. Other tunneling protocols may have larger headers and may require larger MTU values. Fragmentation within MPLS network is not allowed.
Therefore, it is extremely important to configure MTU appropriately so as to not drop traffic in the core or the service provider network. One of these links is in forwarding mode and is in blocking mode. Which link is in which mode depends on the placement of the MST root bridge. Cisco series platforms with Cisco IOS release Consider this solution even in situations in which all Layer 2 switches within the data center do not run the MST protocol.
However, depending on the data center design, there are several options for performing MAC-address flushing. Due to the insertion of a U-PE switch, there is no affect to the distribution device. EEM scripts are required on the intermediate U-PE switch instead of the aggregation switches as in option 4a. This design enables faster convergence time because the backup pseudowire always is up and ready for use. IOS native Yes The data center infrastructure is central to the IT architecture, from which all content is sourced or passes through.
It is critical to properly plan the data center infrastructure design, and to carefully consider performance, resiliency, and scalability. Data center design should also address flexibility to enable quickly deploying and supporting new services.
Designing a flexible architecture that efficiently supports new applications can provide a significant competitive advantage.
Such a design requires solid initial planning and thoughtful consideration of port density, access layer uplink bandwidth, true server capacity, oversubscription, and various other factor The data center network design is based on a proven layered approach, which has been tested and improved over several years in some of the largest data center implementations.
The layered approach provides the basic foundation of a data center design that improves scalability, performance, flexibility, resiliency, and maintenance. Figure shows the basic layered design. The core layer provides connectivity to multiple aggregation modules and provides a resilient Layer 3 routed fabric with no single point of failure. Server-to-server multi-tier traffic flows through the aggregation layer and can use services such as firewall and server load balancing to optimize and secure applications.
The smaller icons within the aggregation layer switch in Figure represent the integrated service modules. These modules provide services, such as content switching, firewall, SSL offload, intrusion detection, network analysis, and more. The server components consist of 1 RU servers, blade servers with integral switches, blade servers with pass-through cabling, clustered servers, and mainframes with OSA adapters.
These emerging technologies are restricted to server access and cannot currently be extended via VPLS. Figure illustrates interconnected data centers. Dual N-PE routers have been added in addition to core, aggregation, and access layers in each data center.
Two VLANs were provisioned for connectivity to public and private networks. These VLANs were then extended across data centers via pseudowire schemes as described in the solution section. End-to-end service validation was performed by using traffic tools to generate IP unicast, multicast, and simulated voice traffic on the network. Health checks were performed before and after each test. These checks included memory and CPU utilization, tracebacks, memory alignment errors, deviations in number of routes and mroutes, interface errors, line card status and syslog messages.
These names were selected to reflect remote locations or represent geographically dispersed locations and are not meant to imply the actual distances between these locations.
The data centers were collocated in a lab with back-to-back fiber connections. Hardware and Software Device Information Table provides information about the hardware and software that was used during testing. In this test suite, convergence is measured from the data source to the receiver end-to-end network convergence.
During convergence, packet loss is determined for each individual flow. For example, packet rate of pps corresponds to 1 millisecond ms convergence time for each packet dropped. Traffic Flow Even though three data centers are used in all the designs documented in this guide, only two data centers, namely London and San Jose were used for convergence tests.
Unidirectional traffic flows were provisioned across two data centers. For each traffic type, i. Thus the total number of unidirectional traffic flows from London to San Jose were and from San Jose to London were This special pseudowire is not blocked by STP nor used to forward any data packets. However, this feature requires that the access network be designed so that one of the N-PEs is always the root of MST.
This configuration requires that the root and backup root bridge be moved from the aggregation to the WAN edge layer. Therefore, any topology changes in MST instance 0 are propagated to all switches.
This approach prevents propagation of STP notifications and topology changes. Configuring MST in pseudowire is a two-step process: 1. The following provides snippets of configuration from N-PE and aggregation devices and output from various show commands. Configure N-PE1 as the root bridge for MST instance 0 and 1 by reducing the bridge priority to a value lower than the value found in step 1.
Current configuration : bytes! Ensure that all Layer 2 switches in the local data center are running MST. On Agg-1 , Agg-2, Access-1, and Access spanning-tree mode mst! Configure a higher cost on the aggregation switch link connected to N-PE so that regardless of the bandwidth of the inter-aggregation switch link, the inter-aggregation switch link always is in forwarding mode for all VLANs. MySQL High Availability explains how to use these replication, cluster, and monitoring features in a wide range of real-life situations.
Written by engineers who designed many of the tools covered inside, this book reveals undocumented or hard-to-find aspects of MySQL reliability and high availability -- knowledge that's essential for any organization using this database system.
Explore the binary log, a file for replication that helps in disaster recovery and troubleshooting Get The chapters are comprehensive and the flow of concepts is easy to understand. This book explains those factors in a way that smoothes the path to implementation and management. Whether you need an introduction to the technologies, a refresher course for IT managers and data center personnel, or an additional resource for advanced study, you'll find these guidelines and solutions prov This practical book explains replication, cluster, and monitoring features that can help protect your MySQL system from outages, whether it's running on hardware, virtual machines, or in the cloud.
Written by engineers who designed many of the tools covered, this book reveals undocumented or hard-to-find aspects of MySQL reliability and high availability-knowledge that's essential for any organization using this database system.
0コメント