Two NIC using computer as switch

                                         |====|
       FiOS           Switch/LB6M        |    |
   [_...__...°]------>[_...__...°] ----->|____| Desktop / Ubuntu
         |  |    W1      | | |      W2   
         |  |            | | |    
         |  |            | | |
         v  v            v v v
  [wifi/other]          [.....°]
                        [.....°]
                        [.....°] Cluster / Ubuntu

Above is my current configuration. FiOS is acting as DHCP server for all. Desktop, cluster nodes and others are using same network. 10.0.0.xxx

I am trying to coect W1 to the desktop so that i am able to tu on the switch only when the cluster is ruing and keep off other time.

W2 and all coection from Switch to Cluster nodes are 10GbE.

I need the nodes on cluster to be able to access inteet from FiOS for updates as well as desktop be able to coect to nodes. For the speed, most of the data flows between each other over 10GbE and switch. I will be able to assign static ip to switch, nodes on cluster and the desktop.

I want to avoid parallel wire like W1 going from FiOS to Desktop. I am thinking of adding 4 hub un-managed switch to fork W1 to the switch and desktop would like to avoid that if i can use desktop as transparent port for switch to rest of the network.

Will there be any performance penalty on data transfer if using new switch or desktop in between.

I am fairly new in advance networking, but have fair linux experience. Can you please suggest any pointers, terms that i need to look at or any other suggestion.