Simplified, High-Performance 10GbE Networks Based on a Single Virtual Distributed Switch, Managed by VMware* vSphere 5.1

Table of Contents
1 Executive Summary .................................. 1
2 Overview: Evolution of Virtual Switches
to Enhance Efciency and Performance ................ 2
2.1 Managing Virtualized Trafc within
a Single Host with VSSs ................................2
2.2 Managing Virtualized Trafc across
Up to 350 Hosts with VDSs .............................4
3 Multiple Approaches to Virtualized
I/O Resource Sharing ................................. 5
4 Software Entities at the Heart
of the Virtualized Network ............................ 6
4.1 Virtual Network Interface Cards (Virtual NICs) ...........6
4.2 Port Groups and Distributed Port Groups ................ 6
4.3 VLANs and Private VLANs .............................. 6
5 Superior Trafc Management
with VDS-based Networking .......................... 7
5.1 Network Resource Management ........................9
5.2 Network Path Redundancy .............................9
6 Management and Security
for Virtual Networks and the Cloud ...................10
6.1 Network Management: VMware vCenter Server ........10
6.2 Health Check .........................................10
6.3 Network Rollback and Recovery .......................10
6.4 VMware ESXi* Dump Collector support .................11
7 Conclusion .......................................... 11
2 Overview: Evolution of Virtual Switches
to Enhance Efficiency and Performance
Large-scale virtualization involves the use of combinations of
virtual and physical networking components. Therefore, virtual
switches must provide similar capabilities to those of physical
switches in areas such as HA, quality of service, and security. It
must also perform that management at the data center level,
rather than at the level of a single physical host or isolated
segment of the virtual network. A single VMware VDS can handle
interconnections among virtual machines (VMs) on as many as
500 physical hosts, and a single vCenter instance can include as
many as 128 VDSs.
Simple server consolidation using virtualization replaces individual
servers with VMs, many of which can reside together on a single
host. Whereas networking among the non-virtualized servers
was based on cables, switches, and other physical components,
networking among the VMs requires the addition of virtualized,
software-based components. The simplest form of virtual networking
replaces the physical top-of-rack switch with a software-based
virtual switch that runs on the physical host, as shown in Figure 1.
A virtual switch works like a Layer 2 physical switch.
2.1 Managing Virtualized Traffic
within a Single Host with VSSs
In the non-virtualized version of the model shown in Figure
1, dedicated servers were often used to host specic
applications, for technical reasons such as using a specic OS,
for business reasons such as isolating payroll information, or
for legal reasons such as meeting regulatory requirements.
LAN connections between individual servers and the top-of-
rack switch were typically based on two 1GbE connections for
redundancy. Particularly network-intensive workloads might be
accommodated by additional 1GbE connections between the
server and the switch. In either case, certain limitations arose.
• Inflexible topologies. Physical connections segmented network
bandwidth into dedicated 1 Gb connections for different
traffic types, which could not easily be changed, decreasing
flexibility. To add bandwidth required physically connecting and
configuring new connections at the server and the switch.
• Inefficient designs. Network architects were forced to assign
extra bandwidth to servers by using link aggregation of multiple
connections, to handle workload peaks leading to poor overall
utilization of network resources.
• Prevalent bottlenecks. Even with link aggregation, connections
were still limited to a maximum of 1 Gb per session and required
additional switch configuration and coordination. Trying to
provide enough bandwidth for peak times on each of these
dedicated connections often put strain on budgets, because
over-provisioning was necessary to avoid not having enough
throughput available when it was needed.
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Simplied, High-Performance 10GbE Networks Based on a Single Virtual Distributed Switch, Managed by VMware vSphere* 5.1