SCVMM Logical Networks Test

You have different types of networks in your organization, including corporate networks, management networks, and others. In VMM each of these networks is defined as a logical network. Logical networks are logical objects that mirror your physicals networks.

When you create logical networks, you assign them properties that match your physical environment. You specify the type of network, the associated network sites associated, and the static address pools if you're not using DHCP to assign IP addresses to VMs you create in the network sites. You also specify whether networks are isolated physically or virtually, using network virtualization and virtual LANs (VLANs).

To know what are logical networks that have been configured and what their properties are, use the SCVMM Logical Networks test.

This test auto-discovers the logical networks that have been defined in VMM, and reveals the properties that have been enabled for each. This way, you can rapidly identify the logical networks for which network virtualization has been enabled, VLANs have been enabled, or GRE is used.

Target of the test : SCVMM

Agent deploying the test : An internal agent

Outputs of the test : One set of the results for the logical networks defined in the target VMM

Configurable parameters for the test
Parameter Description

Test Period

How often should the test be executed.

Host

The IP address of the SCVMM server being monitored

Port

The port at which SCVMM listens. The default is 'null'.

Domain, Username, Password, and Confirm Password

The eG agent runs PowerShell scripts on SCVMM to pull metrics. To run these scripts, the eG agent requires the permission of an SCVMM administrator with 'read-only' privileges. In order to grant this permission to the eG agent, configure the Username and Password parameters of this test with the credentials of an SCVMM administrator with 'read-only' privileges. Confirm the password by retyping it in the Confirm Password text box. Then, specify the domain to which this user belongs against the Domain text box.

DD Frequency

Refers to the frequency with which detailed diagnosis measures are to be generated for this test. The default is 1:1. This indicates that, by default, detailed measures will be generated every time this test runs, and also every time the test detects a problem. You can modify this frequency, if you so desire. Also, if you intend to disable the detailed diagnosis capability for this test, you can do so by specifying none against DD frequency.

Detailed Diagnosis

To make diagnosis more efficient and accurate, the eG Enterprise suite embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test for a particular server, choose the On option. To disable the capability, click on the Off option.

The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled:

  • The eG manager license should allow the detailed diagnosis capability
  • Both the normal and abnormal frequencies configured for the detailed diagnosis measures should not be 0.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Is network virtualization enabled?

Indicates whether/not network virtualization has been enabled for this logical network.

 

By default, if you're using isolated VM networks in your VMM fabric, VMs associated with a network can only connect to machines in the same subnet. If you want to connect VMs further than the subnet, you will need a network virtualization gateway.

You set up network virtualization so that multiple VM networks are overload on the VMM logical networks that model your physical network topology and thus decouple the VM networks from the physical network infrastructure.

The values that this measure reports and their corresponding numeric values are listed in the table below:

Measure Value Numeric Value
Yes 1
No 0

Note:

By default, this measure reports the Measure Values listed in the table above to indicate whether/not network virtualization has been enabled. In the graph of this measure however, the same is indicated using the numeric equivalents only.

If this measure reports the value Yes, then use the detailed diagnosis of this measure to view the complete details of the logical network, which includes its isolation type, its accessibility mode (public or private), the names of adapters, and the hosts.

Is generic routing encapsulation (GRE) used?

Indicates whether/not network virtualization uses NVGRE(Network Virtualization using Generic Routing Encapsulation) for this logical network.

 

This measure is reported only if the Is network virtualization enabled? measure reports the value Yes for a logical network.

Network virtualization uses NVGRE (Network Virtualization using Generic Routing Encapsulation) to virtualize IP addresses. In NVGRE, the virtual machine's packet is encapsulated inside another packet. The header of this new, NVGRE-formatted packet has the appropriate source and destination provider area (PA) IP addresses. In addition, it has a 24-bit Virtual Subnet ID (VSID), which is stored in the GRE header of the new packet.

The values that this measure reports and their corresponding numeric values are listed in the table below:

Measure Value Numeric Value
Yes 1
No 0

Note:

By default, this measure reports the Measure Values listed in the table above to indicate whether/not network virtualization uses NVGRE. In the graph of this measure however, the same is indicated using the numeric equivalents only.

Is private VLAN enabled?

Indicates whether/not private VLANs are enabled for this logical network.

 

In a VMM, you can isolate VM Networks using either traditional VLAN/PVLANS or, or using network virtualization.

Private Virtual LANs (PVLANS) are often used by Service Providers (Hosters) to work around the scale limitations of VLANS. They essentially allow network administrators to divide a VLAN into a number of separate and isolated sub-networks which can then be allocated to individual customers (tenants). PVLANs share the IP subnet that was allocated to the parent VLAN. However, from a security perspective, although hosts connected to different PVLANs still belong to the same IP subnet, they require a router to communicate with each other and with resources on any other network.

The values that this measure reports and their corresponding numeric values are listed in the table below:

Measure Value Numeric Value
Yes 1
No 0

Note:

By default, this measure reports the Measure Values listed in the table above to indicate whether/not PVLANs are enabled. In the graph of this measure however, the same is indicated using the numeric equivalents only.

If the Is network virtualization enabled? measure reports the value Yes, then use the detailed diagnosis of this measure to view the complete details of the logical network, which includes its isolation type, its accessibility mode (public or private), the names of adapters, and the hosts.

Figure 2 : The detailed diagnosis of the Is network virtualization enabled? measure