GNS3 / GNS3/dynamips

Clarification of dynamips behavior regarding tap interfaces

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C
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Description

Let's assume this configuration:

dynamips \
        -i R1 \
        -X \
        -T 1024 \
        --idle-pc=0x6062dbb8 \
        -p 0:C7200-IO-FE \
        -s 0:0:tap:tap1 \
        -p 1:PA-FE-TX \
        -s 1:0:tap:tap3 \
        c7200-adventerprisek9-mz.152-4.M11.image

In my observation, this is what happens in regard to tap3 (we'll ignore tap1):
If the device does not exist on the host OS level at startup of dynamips, dynamips will create it (assuming sufficient permissions of the user account starting dynamips) and destroy the device when dynamips is being shut down.
If the device does exist on the host OS level at startup of dynamips, it'll be used as is and not destroyed when dynamips is being shut down.

That behavior is perfectly acceptable as far as I am concerned, though I did not find a description of the behavior in the documentation and want to make sure this behavior can be assumed to be consistent.

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First steps

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  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the existing documentation for dynamips tap interfaces and the shown dynamips command using tap3. Verify the described startup and shutdown behavior for pre-existing and newly created host interfaces, then document the confirmed behavior and any relevant permission requirements.

Written by the indexing model from the issue text.

Assessment

Domain
documentation, networking
Issue type
Documentation
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
48/100

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