Virtualization has a severe impact on the data network infrastructure. The data network infrastructure has two components, a storage network infrastructure and an end-user or web infrastructure component. The focus of the storage network is performance and reliability with relatively few connection points. Fibre Channel is the traditional and most popular end-to-end protocol used within storage networks. Ethernet is almost exclusively used for the end-user networks, because of its suitability for managing large numbers of connection points and dynamic reconfiguration of the network. In large IT data centers there are currently two separate networks with different switches, cabling and management. In smaller IT data centers, iSCSI over Ethernet is used instead of Fibre Channel, often over a separate Ethernet network.
It is very rare that separate networks are used for NAS protocol use, generally this is used over the general purpose LAN. High performance NAS use cases (such as VMware NAS datastores) require the same degree of planning and design as iSCSI or Fibre-Channel.
Converged 10 Gigabit Ethernet networks are emerging as a viable new option, today from hosts to top of rack switches, but is expected to reach deeper into the core LAN/SAN networks over time.
Virtualization bring two main challenges to the network infrastructure:
- Successful virtualization means that the servers are running at much higher utilizations. As a result more network and storage adapters are required in the servers to meet the data rates.
- It is much easier to move workloads between servers. As a result, servers need to be equipped with all the network cards to handle different workloads types.
The result is virtualization servers that have many cards. These cards need to be connected to the network infrastructure with cables connecting to the switches. As servers get smaller, cabling of servers is a severe constraint to effective utilization of floor space. Heat density is also an increasingly challenging problem.
The solution to this is to virtualize the adapters and provision fewer higher speed adapters that can run multiple storage and network protocols. These adapters are called Converged Network Adapters (CNAs) and is an important trend in networking that supports virtualization. The new Ethernet 10GbE standards allow the encapsulation of end-to-end storage protocols such as Fibre Channel (FC) within the Ethernet frames. FC over Ethernet is called FCoE. This allows servers to be configured in a general way, and be able to support workloads with either high storage traffic over the FCoE portion, and support user and web traffic over Ethernet.
Another key simplification initiative is to connect the network logically to a vApp construct and make a virtual machine, not a port, the end point of the network. In the same way that storage LUNs become invisible in a virtualized environment, so will ports.
- Resource Virtualization
- Availability of CNAs and 10GbE cards as standard
- FCoE Network from Server to Top-of-rack Switch
- Broad support for physical interface virtualization (SR-IOV)
- Broad support for logical interface virtualization (VLANs, NPIV, NPV)
- Application Encapsulation
- Ability to define network bandwidth and latency requirements at the vApp level
- Integration of hypervisor APIs for network requirements (e.g. bandwidth and latency)
- Integration of networks to provide end-point (Virtual Machine) level policy and control.
- Internal location independence
- Support of Virtual Networks
- FCoE extended out to Storage Arrays through common Ethernet Switched Infrastructure that support FCoE fully (including multihop)
- Native FCoE support on Storage Arrays
- Extension to VMware & network architecture that will allow network to logically connect to vApp and not a port(s) (requires extension to Ethernet Frames, e.g., CISCO VNLink)
- Network software is aware of virtual Networks and supports mapping of real ports to vApps
- Network supports the ability to move applications and data across the infrastructure non-disruptively and at high speed
- Network supports the ability to create and exploit an active/active topology for remote and local high-availability replication services
- External location Independence
- Enhanced security and monitoring for Virtual Networks
- Network supports multi-location data recovery including external resources
- Infrastructure capabilities to support geographic datacenter dispersion and hybrid cloud import/export will become increasingly important over time.
Footnotes: This research is an expansion of a section of research looking into The Value of the VMware Integration Journey