Conference 7.286::fddi

Hi Bob,

> 1) I believe the 2 PMC-FDDI NIC's need to be on the same Subnet, in order
>    for them to make a FDDI "ring" -- is this correct?

No. The formation of a "ring" is completely a function of the PMC-FDDI
adapter itself.  Each adapter simply needs to be "enabled" by the host
computer and ring formation happens.

The adapters need to be in the same subnet in order for a higher level
protocol to work.

> 2) Do the VME-FDDI IP Addresses need to be on the same Subnet as the 
>    PMC-FDDI, if these 2 NIC's are NOT communicating directly to one 
>    another?
> 3) What about the Ethernet IP address?

Typically no.  The usual situation (that is, no router) is for each
physical lan segment to have its own IP subnet.  This is how the node
decides on which segment to send a packet: it looks at the subnet
and then steers the packet to the appropriate physical device.
 
> 4) Will the one CPU be able to control the 3 network interfaces, assuming
>    the correct Unix drivers are configured?

Yes.

These systems would have five IP subnets defined:

	1. Ethernet 1
	2. Outside VME-FDDI 1
	3. PMC-FDDI to PMC-FDDI
	4. Ethernet 2
	5. Outside VME-FDDI 2

Regards,
Chuck

    
    Thanks for your answers, Chuck.
    
    If I were on the SBC in Backplane #1 and "pinged" a system 
    connected via Backplane #2's VME-FDDI network interface, 
    would this get "resolved" (maybe routed is a better word),
    given the configuration in .1 WITH the 5 different subnets
    as suggested in .2?
    
    -BobF

         	 VME Backplane #1
		+----------------+
  Ethernet ---->| SBC | PMC-FDDI |----+
		|----------------|    |
      outside --|    VME-FDDI    |    |  <---- SAS connections
      network	+----------------+    |
				      |  10. 20. 30. xx
				      | 255.255.255.000
				      |
         	 VME Backplane #2     |
		+----------------+    |
		| SBC | PMC-FDDI |----+
		|----------------|
		|    VME-FDDI    |----------------> DAS to AS600 (DEFPA-DA)
		+----------------+  10. 20. 40. xx
                                   255.255.255.000

?    If I were on the SBC in Backplane #1 and "pinged" a system 
?    connected via Backplane #2's VME-FDDI network interface, 
?    would this get "resolved" (maybe routed is a better word),
?    given the configuration in .1 WITH the 5 different subnets
?    as suggested in .2?
    
I've arbitrarily added some network numbers/masks to the picture to
make talking easier.

The SBC in Backplane #1 is pinging somebody on network 10.20.40, how's
this work?  First, since SBC does not have a locally connected network
number 10.20.40 it needs a router to resolve where the packet goes.
Suppose you set up SBC #2 as a router.  Then SBC #1 would have SBC #2's
address on network 10.20.30 as its Default Gateway.  Routing protocols
then kick in and SBC #1 learns to send traffic for network 10.20.40
out its own network 10.20.30.  SBC #2 in router mode would forward
traffic received on network 10.20.30 which is destined for network 10.20.40.

This is IP networking fundamentals and not specific to FDDI.

Chuck

    
    Thanks Chuck.
    
    Your right about it being IP fundamentals...I didn't see
    such a Notes Conference.  Are you aware of a TCP/IP conference?
    
    -Bob

SMURF::INTERNET_ARPA

    
    Thanks, the conference is SMURF::ARPA_INTERNET
    
    -Bob