Kheeran D's List: New Data Centre

• Veritas Cluster Server, HP TruCluster Server, Microsoft Windows NT/2000 Cluster Services (MSCS), Solaris Sun Cluster, HP Open VMS, and IBM Parallel Sysplex are examples of software that implement clustering functions. Some of these applications require that servers participating in the cluster be on the same IP subnet. The reason for this could be that heartbeats between the servers are not routable or that upon failure the same IP address that was active on one server becomes active on the surviving server.
• Veritas Cluster Server, HP TruCluster Server, Microsoft Windows NT/2000 Cluster Services (MSCS), Solaris Sun Cluster, HP Open VMS, and IBM Parallel Sysplex are examples of software that implement clustering functions. Some of these applications require that servers participating in the cluster be on the same IP subnet.
• Limit the scope of the Layer 2 environment to simplify spanning tree topology and speed convergence
• Provide multiple levels of redundancy to provide a tiered defense against multiple failures and to permit the fastest convergence
• Synchronous implementations utilize low-latency networks such as a LAN or optical networks when data centers are no more than 100 kilometers (km)

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• Cisco recommends isolating and reducing Layer 2 networks to their smallest diameter

  • Lochlan said the Cisco position was the opposite of this.
• High-availability clusters, server migration, and application mobility are some important use cases that require Layer 2 extension.
• Because the different data centers are independent bridged domains, it is beneficial to isolate their respective spanning trees
• Virtual Private LAN Services, or VPLS, is a class of VPN that supports the connection of multiple sites in a single bridged domain over a managed IP or MPLS network. VPLS presents an Ethernet interface to customers, simplifying the LAN or WAN boundary for enterprise customers and enabling rapid and flexible service provisioning, because the service bandwidth is not tied to the physical interface. All services in a VPLS network appear to be on the same LAN, regardless of location (Figure 16).

      

  VPLS uses edge routers that can learn, bridge, and replicate on a per-VPN basis. These routers are connected by a full mesh of tunnels, enabling any-to-any connectivity. VPLS operation emulates an IEEE Ethernet bridge.
• This approach allows the enterprise to build EoMPLS point to point across connections between two sites while these connections are being transported over the existing IP core. MPLS does not need to be deployed in the core network.

  • This seems like the most likely fallback we might need to adopt.
• The multipoint characteristic of VPLS allows easy evolution of the global architecture, with flexibility to incorporate new sites without service disruption.

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