|Applicable Versions||NetSim Academic||NetSim Standard||NetSim Pro|
In a network architecture, different layers have their own addressing scheme. The application layer uses hostnames, network layer uses IP addresses and the link-layer uses MAC addresses. Whenever a source node wants to send an IP datagram to a destination node, it needs to know the address of the destination. Since there are both IP addresses and MAC addresses, there needs to be a translation between them. This translation is handled by the Address Resolution Protocol (ARP).
The static ARP entries are address resolutions that are manually added to the cache table for a device and are retained in the cache on a permanent basis.
Static ARP settings can be found in the Static ARP Configuration tab which is part of the Run Simulation window that appears after clicking on the RUN button.
The different modes available for static ARP in Netsim are as follows:
1. Enable (Auto):
2. Enable (using file)
Static ARP can be enabled/disabled using Static ARP configuration option available in the Run Simulation window
- In NetSim static ARP option is enabled by default, due to which ARP messages will not be exchanged between devices during the simulation. This is assuming that the ARP tables are already updated prior to the simulation.
- If static ARP is disabled, then ARP tables will be empty during the start of the simulation and hence ARP messages are exchanged between the devices to update the ARP tables.
This can be observed in packet trace and Netsim Packet animation as follows:
In packet trace window, ARP packet flow can be observed by filtering Control Packet Type to ARP Request and ARP Reply
In the Animation window, we can see the flow of ARP Request and Reply packets as:
- If static ARP is set to Enable(file), the user can pass a file with ARP route table information as input to the simulation. ARP tables of nodes will be updated based on the input file and hence ARP messages will not be exchanged between the devices.
The standard format for ARP File is as follows: