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Link Control


available in GNS3 version 2.1 and later.

Packet Filters

Packet filters can be applied on links without stopping any node.

Supported packet filters are:

  • Frequency_drop drop a packet every x packets.
  • Packet_loss randomly drop a packet
  • Delay: adds latency and/or jitter.
  • Packet_corruption randomly corrupt a packet.
  • BPF_(Berkeley_Packet_Filter) filter packets matching a BPF expression.

All packet filters can be combined, meaning you can apply both a packet loss filter and a delay filter on the same link that will be active simultaneously.

To apply a packet filter, right-click on a link, and select Packet filters:


As an example, click the Delay tab, add a non-zero value for Latency, then click Apply:


The icon on the Delay tab changes from a red square to a green circle, indicating it’s active:


Click OK to close the Packet filters window:


A filter icon will be displayed on the link to indicate one or more packet filters are active.


It is possible to suspend a link. For instance, to simulate a temporary connectivity issue in your project. Suspending a link currently means that all packets going through the link will be dropped.

To suspend a link, right-click it and then select Suspend:


The link is now suspended, so no traffic can pass through it: