Yesterday I covered the detail associated with the launch of VMware's vSphere product and that it not only delivered HUGE performance gains, but had over 150 new capabilities that were not present in previous software products, such as VMware's Virtual Infrastructure.

A number of these enhancements have taken place at the switching and networking layer.
vSphere 4 has claimed to be able to deliver enough network I/o to saturate a 10Gbps for transmit and recieve, this is primarily due to the direct improvements for the VMkernel TCP/IP stack.

One of the capabilities that is included in vSphere is VMXNET Generation 3 or VMXNET3. It has additional features such as :

• VLAN Off-loading
• Large ring sizes for TX/RX - this is able to be configured from within the virtual machines
• TCP Segmentation offloading over IPv6
• IPv6 Checksums
• Windows 2008 side scaling support - enabled through the virtual machine on the adapters properties tab

The most exciting functionality in networking enhancements for vSphere is the distributed switch, which allows configuration of one vNetwork Switch for multiple hosts.
A distributed vNetwork Switch is the key feature that allows the scalability enhancements on the network side and opens up a world of possibilities that featuresets like Fault Tolerance leverage.

The vNetwork switch is also the basis of which the Cisco Nexus series switching is built upon, allowing administrators who are familiar with Cisco switching to expand upon the inbuilt switching featuresets, and integrate the virtual switching environment tightly into the datacenter. This has Operational benefits as well, reducing the time required to ramp up to vSphere and the next generation datacentre.
In summary there are three types of vNetwork switch options available for vSphere.

VMware vNetwork Standard Switch

The best description of this switch is that is is a host only switch, and has carries through all of same capabilities that a vSwitch in ESX 3.5 had plus some additions.

VMware vNetwork Distributed Switch (vDS)

The vDS is an extends the capabilities of the vNetwork standard switch because it is a single switch that is distributed across multiple servers in the datacenter.

Cisco Nexus Series Switches

The Nexus is a virtual switch developed in partnership with VMware and Cisco that allows extension of the capabilities that the VMware vNetwork Distributed Switch adds. The extensions to the capabilities are nothing short of astounding and include :

• IGMPv3 Snooping
• Virtual PortChannels
• Link Aggregation Control Protocol
• Source and Destination MAC addresses for load balancing
• Source and destination port IP for load balancing
• Additional hashing options for load balancing
• Differentiated Services Code Point (DCSP) for QOS
• Type of service for QOS
• Class of service for QOS
• Local PVLAN enforcement
• Access Control Lists (ACLs)
• IP Source Guard
• Dynamic Address Resolution Protocol (ARP) Inspection (DAI)
• Switched Port Analyzer (SPAN)
• Simple Network Management Protocol (SNMP) v3 Read and Write
• Packet Capture and Analysis
• RADIUS and TACACS support

More detail on all of these featuresets can be obtained via VMware's website and Cisco's website, but there is bound to be an option to suit your roadmap and strategy.