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

• Enabling or disabling LACP on an uplink port group. Link
Aggregation Control Protocol (LACP) on a vSphere distributed
switch provides a method to control the bundling of several
physical ports together to form a single logical channel. LACP
on a vSphere distributed switch allows network devices to
negotiate automatic bundling of links by sending LACP packets
to a peer. LACP sends frames down all links that have the
protocol enabled. If it finds a device on the other end of the
link that is also LACP enabled, it independently sends frames
along the same links, enabling the two units to mutually detect
multiple links and then combine them into a single logical link.
Note that the preferred method used to provide redundancy
for iSCSI traffic is to use multiple paths (MPIO), which is not
supported on LACP-enabled uplinks. Likewise, FCoE connections
also need special configurations if LACP is used. See the
VMware vSphere 5.1 Storage Configuration documentation
for more details.
6 Management and Security
for Virtual Networks and the Cloud
Software tools from VMware are vital to the transition in mindset
away from physical segmenting and static bandwidth allocation,
to distributed switching and dynamic bandwidth re-allocation.
Utilizing automated resource management in both the data
center and the cloud lets the network tune resource usage as
needed, in real time, with security deeply intertwined with the
architecture’s approach to administration. Key management tools
that are either incorporated into vSphere or designed explicitly
for ease of integration with it are described below.
6.1 Network Management: VMware vCenter Server
As the central management console for the vSphere
environment, VMware vCenter Server provides both operational
control and proactive management of all virtual and physical
resources, including VMs, physical hosts, and virtual switches.
VMware vCenter Server automates the robust dynamic network-
resource allocation described in this paper, eliminating the
guesswork and inefciency associated with static assignments
of bandwidth.
6.2 Health Check
VMware vSphere 5.1 Health Check helps identify conguration
errors in distributed switches, including mismatched VLAN trunks
between a distributed switch and physical switch; mismatched
Maximum Transmission Unit (MTU) settings between physical
network adapters, distributed switches, and physical switch
ports; and mismatched virtual teaming policies for the physical
switch port channel settings. Health Check monitors the following:
• VLAN. Checks whether the physical access switch port VLAN
trunk configuration matches the distributed switch distributed
port group VLAN range setting.
• MTU. Checks whether the physical access switch port MTU
jumbo frame settings per VLAN matches the distributed
switch MTU setting.
• Teaming policies. Checks whether the physical access switch
ports’ EtherChannel setting matches the distributed switch
distributed port group IPHash teaming policy settings.
6.3 Network Rollback and Recovery
vSphere network rollback can help prevent accidental
misconguration of management networking and loss of
connectivity to the host by rolling back to a previous valid
conguration. In vSphere 5.1, rollback is enabled by default.
However, you can enable or disable rollbacks at the vCenter
Server level. Several networking events can trigger a rollback,
including the following:
• Host networking rollbacks occur when an invalid change is
made to the host networking configuration. Every network
change that disconnects a host also triggers a rollback.
• Distributed switch rollbacks occur when invalid updates are
made to distributed switch-related objects, such as distributed
switches, distributed port groups, or distributed ports.
If an invalid conguration for any of the changes occurs, one
or more hosts will be disconnected from the vCenter server.
The recovery option in vSphere 5.1 allows administrators to
connect directly to a host and x distributed switch properties
or other networking miscongurations using the DCUI. The
rollback and recovery features provide the required reliability to
the vSphere Distributed Switch to avoid management network
conguration issues.
The ESXi core dump client, Dump Collector, sends VMkernel
core contents to a network server when the system encounters
a critical failure.
ESXi 5.1 Dump Collector supports both vSphere standard and
distributed switches, as well as Cisco Nexus* 1000 series
switches. Dump Collector can mark 802.1pq tags on dump packets
when congured to do so. Dump Collector can also use any
available uplink when the port group the collector is congured
on is connected to a team.
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Simplied, High-Performance 10GbE Networks Based on a Single Virtual Distributed Switch, Managed by VMware vSphere* 5.1