I think bidirectional ports and links are fine as the current 'group' concept.  They provide a useful shorthand for those that wish to use them, but 
do not need to be first class citizens of the schema.  

So yes - close the issue, since its a non issue.  

This is embarrassing: I don't remember what this was about.

I can imagine a few things:
1) introduce bidirectional links as "first class citizens" (to paraphrase Jason).
2) find a way to support undirected links (see artf6533 in the use cases)

As for 1): Roman brought it up again, and Jason wrote something similar in the NML examples after OGF 33 (see line .. at https://forge.ogf.org/svn/
repos/nml-examples/201109-switchservice/2vlans_option1.xml). I like bidirectional ports too, but rather spent my time on other issues right now. I 
would support proposals from others, but right now won't pick it up myself.

As for 2): I like to support this use case, but don't know how right now.

In either case, I don't know what this is about, and either don't want to take it up or don't know how to take it up, so I unassign myself. Can we 
close this?