- Technical Information
Presented below are the bandwidth requirements for NetLab and/or a similar setup:
- Network Connectivity Requirements (NETLAB+ Host Site)
- 5.0 Mb/s or higher Internet connection, with higher outbound burst capability
What we have setup in our current proposed lab environment are 20 workstations with 1Gb/s NIC cards in each as well as a vCenter server which also has a 1 Gb/s NIC card. The middle man between the two are two 2960 switches that are trunked together with a 1 GE connection. This will work, however this will not allow all of our host machines to operate at their full networking capabilities.
A proposed solution would be to eliminate one of the 2960 switches. From here we would use the 2960 switch that remains and take advantage of it’s two 10G ports. These 10 ports would then connect directly to the two 10G ports on the vCenter server. This is turn will allow for better throughput for the host machines to operate at their full networking capabilities.
Network testing specific
What has been done:
- Initial setup of PRTG and Kiwi (decided not to use this software since it duplicated abilities found in the others used with no additional benefit) in personal test environment.
- Additional configuration and testing needed to determine the best way gather network data. It was decided through this testing to use vCenters built in monitoring software and PRTG for the switch data.
- Initial data seems to be good, hard to tell without the ability to simulate large amounts of network traffic.
PRTG Network Monitor
- Allows up to 10 “sensors” (data collector sets) on the freeware version
- Uses SNMP polling to get its data
In this case the data will be provided by the Cisco switches in the classroom. Will be able to determine network load over time and compare real numbers coming from devices.
- Requires the SNMP settings be placed on the switches and configured to talk to the SNMP server
- Software uses a web interface to provide management of the SNMP server
- Alarms and reporting handled in the software
vCenter’s built in monitoring of its attached hardware
Allows direct view of hardware resources being accessed by Vcenter
Creates no extra overhead from additional software or services having to be run on a VM or physical hardware. Allows for historical monitoring and information can be pushed into excel spreadsheet format to further work with. We will need actual VM’s running to further create the correct metrics to verify we are tracking the needed data. This will allow us to track hard drive performance and CPU usage.
Initial Setup of PRTG walk through:
Startup configuration guru (their version of a wizard)
- Start at the Welcome screen
- Given the option of encrypting the web interface
- Account info setup
- You are allowed to select your version of SNMP to use. I went with v2 since it was the most commonly supported with Cisco devices
- There are built in sensors for monitoring ESXi (something that maybe useful for additional tracking during testing).
- There are additional questions about premade sensors like Mac servers and the like that will not apply to us.
- After the several questions about other network devices you have the option of setting up auto discovery to locate other devices on your network. This only works well on a very small network, I was able to exceed the counters allowed in this version just on my home network. Manual setup for counters will likely be the most reasonable plan for implementation in our test environment.
- Once initial configuration is completed you will be returned to the monitoring page where you can then track and modify the sensors you have set up for the network.
The actual addition of a sensor that tracks the bandwidth the switch is using is fairly straightforward. (Add additional info here on the process)
Traffic generation info here (and concerns).
Switch configuration for the SNMP monitoring:
From the switch the configuration is pretty simple. The following screen capture shows all the commands that are required to setup the monitoring.
The commands are entered in global configuration as you can see in the above capture.
The first command snmp-server community netlabtest1 ro does several things. The snmp-server community is used to set the snmp access string that will be used by the PRTG server for polling the switch. The netlabtest1 portion of the command creates the string name and ro makes it as a read only string. There are large security issues if the string write enabled instead of read, like the total loss of control of your device.
The next command access-list 10 permit 192.168.20.1 0.0.0.0 creates an access list that allows only the PRTG server to poll this switch. This command just adds an additional layer of security.
That command is followed with the snmp-server community netlabtest1 ro 10 command which assigns the access list that was just created to the snmp-community string of netlabtest1.
The final command snmp-server enable traps just activates all the traps that are built into the switch by default. (This is likely not necessary for what we will be using this feature for).
Vcenter Built-in performance monitoring:
Example of what tracking page will monitor:
Cisco’s documentation on SNMP setup: http://www.cisco.com/en/US/docs/switches/lan/catalyst2950/software/release/12.1_9_ea1/configuration/guide/swsnmp.html