I'm not sure if this will be much help; however, since no one is responding, I thought I would give my 2 cents. Before I do though, there are two things I must note. B) I have never worked with ns2 (or ns-3 for that matter) and A) I know almost nothing about FCoE; so my 2 cents on this matter could be worth dog poo.
According to ns2's own wiki, ns2 was designed to simulate TCP(/IP), Routing and Multicasting protocols.
According to wikipedia
, FCoE's protocol takes place of the IP protocol (makes sense, doing it this way allows other networked devices to just ignore what it doesn't understand.)
Data centers used Ethernet for TCP/IP networks and Fibre Channel for storage area networks (SANs). With FCoE, Fibre Channel becomes another network protocol running on Ethernet, alongside traditional Internet Protocol (IP) traffic. FCoE operates directly above Ethernet in the network protocol stack, in contrast to iSCSI which runs on top of TCP and IP. As a consequence, FCoE is not routable at the IP layer, and will not work across routed IP networks.
My summation of all this: Ns-2 probably wont model FCoE out of the box. If you hunt around enough you may find someone who has implemented the FCoE protocol, but this is doubtful.
In fact, the more I read about FCoE, it sounds less like something you'd run through a network simulator, but rather some kind of specialized hardware to do the simulation. The hardware is designed to guarantee packet delivery unlike the normal Ethernet hardware.
Are you sure you're asking the correct question? You may get more help if you explain why you're trying to emulate FCoE "Network" traffic.
Anyway, there's my two cents. I hoped it help.