Navigation:  Structural Engineering Library > Installation, Activation & Licensing > How It Works > Network License Manager

 

Can you explain your Network License Manager?

 

ENERCALC's Network License Manager (NLM) is an alternative to the Internet Activation method of obtaining "permission" to run one or more installations of the Structural Engineering Library (SEL) on your computer(s).

 

When you use the NLM, it becomes the "gatekeeper" that holds your "pool" of available "seats" and it controls your SEL activations.  The SEL communicates with the NLM and "requests" an activation.  As long as you have an available "seat" in your "pool" of licenses, the NLM will grant permission for your SEL to run.  If the NLM finds that you have already used all of your available "seats", then it will provide an informative text box indicating this, and it will give you the option to view a list of currently activated users.

 

There are a couple important features to note:

 

1. Since the NLM becomes the "gatekeeper" for managing your "seats", the individual SEL installations must be able to communicate with the NLM across your LAN.  However, there is no need for Internet access at the individual workstations.  This is an attractive feature for any organization whose policy prohibits all Internet access from the individual workstations.  This also makes the NLM an attractive activation option for large organizations trying to share several seats but that happen to experience unreliable Internet service.

 

2. Although the NLM does have its strengths as mentioned in the previous item, it does have some drawbacks.  One of those drawbacks is that it does NOT allow an activation to be removed from the LAN.  This means that it is not possible to activate a laptop and take it off your "campus" or site.  Please consider the Internet Activation system if this is a necessary function for your activation needs.

 

Some notes of interest:

 

•The NLM itself must actually be Internet Activated when it is first installed.  After that initial activation, it is not necessary for the NLM to maintain Internet connectivity.

•If there is no ability to provide Internet connectivity even for the brief initial activation, it is possible to activate the NLM manually by using a Manual Activation Code that is generated by ENERCALC specifically for the server that the NLM resides on.

 

For additional information see the following: www.enercalc.com/pdf/EC_Activation_Network.pdf

 

 

 

How does the Network License manager communicate between all the computers ?

 

The ENERCALC Network License Manager (NLM) uses broadcasting to make itself known to the client computers.  When a copy of the Structural Engineering Library (SEL) is started, it also broadcasts its presence on the network, which the Network License Manager will detect.  Broadcasting and IP address sensing is performed this way:

 

The Network License Manager uses two types of data broadcast:
 

▪An "I Can Do" broadcast (used to tell the other machines that the NLM is running) is actually broadcast to all machines on your LAN. This means only one packet leaves the server, but every machine on your LAN can read it in one go.
 
The packets are also sent to all "Additional IP Addresses" you have added to the NLM's list.
 

▪A data broadcast (i.e. sending data from the NLM) is sent individually to every machine which is registered in its internal service queue.
 

This way network traffic is kept to a minimum (“I Can Do” packets), but error-recovery is performed on an individual basis (data packets).
 

Each instance of the application (meaning the NLM and the SEL) uses two ports to communicate on.  One TCP and one UDP port are used.
 

The following table shows the default port numbers for each instance running on a machine.  The default number of instances is 5.
 

 

 

 

If the application is connecting over the WAN then these ports need to be open.  Proxy is now supported.