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Conference netcad::hub_mgnt

Title:DEChub/HUBwatch/PROBEwatch CONFERENCE
Notice:Firmware -2, Doc -3, Power -4, HW kits -5, firm load -6&7
Moderator:NETCAD::COLELLADT
Created:Wed Nov 13 1991
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:4455
Total number of notes:16761

2567.0. "DECswitch 900EF and Ethernet frame types" by SNOFS1::KHOOJEANNIE () Thu Jul 27 1995 02:46

    A customer wants an Ethernet to FDDI switch that can handle multiple
    Ethernet frame types.
    
    Currently, he has a Cisco Catalyst, linking Ethernet segments to FDDI
    servers (using Digital FDDI NICs), and is using Ethernet 2, 802.3 (raw IPX)
    and 802.2 simultaneously.  The switch converts incoming Ethernet packets to
    FDDI SNAP format, but for outgoing packets, it converts the 802.2
    packets back, but cannot determine what to do with the others.
    
    Can the DECswitch 900EF handle this scenario?  Any suggestions for this
    customer?                          
    
    Thank you
    Jeannie
T.RTitleUserPersonal
Name		DateLines
2567.1All three cannot co-existNETCAD::KRISHNAThu Jul 27 1995 22:4234
    Jeannie,
         On the DECswitch 900EF, you have the capability to enable Raw
    IPX translation using HUBwatch or SNMP. This applies to all the ports,
    This feature cannot be enabled on a per port basis. Here is the table
    for frame translation both directions:
    
    Ethernet to FDDI
    
    Ethernet Frame Rcvd               FDDI Frame Sent
                                Raw IPX Switch (Disabled)     Enabled
    
    1. Ethernet 2                  FDDI SNAP                  FDDI SNAP
    2. Raw IPX                     FDDI Raw IPX               FDDI SNAP
    3. 802.2                       FDDI 802.2                 FDDI 802.2
    
    FDDI to Ethernet
    
    FDDI Frame Rcvd                   Ethernet Frame Sent
                                 Raw IPX (Disabled)           Enabled
    
    1. FDDI SNAP                   Ethernet 2                  Raw IPX
    2. FDDI 802.2                  802.2                       802.2
    
    So we can handle Raw IPX and 802.2 simultaneously. If the Raw IPX
    switch is enabled both Ethernet 2 and Raw IPX get translated to FDDI
    SNAP frame, when we receive a FDDI SNAP frame in response, we cannot
    distinguish on a per address or even a per port basis as to which were
    speaking Ethernet 2 and which were speaking Raw IPX. So we translate
    all to Raw IPX. If the Raw IPX switch is not enabled all FDDI SNAP
    frames get translated to Ethernet 2. So both Raw IPX and Ethernet 2
    cannot coexist on the same switch.
    
    Hope this helps,
    Krishna
2567.2Another Q on FDDI Raw IPXSNOFS1::KHOOJEANNIEHumpty Dumpty was pushedThu Dec 07 1995 03:2115
    Thanks Krishna
    
    Just to confirm that I understand this:
    
    When an FDDI Raw IPX frame is received, is it converted back to
    Ethernet Raw IPX whether or not the "raw IPX" switch is enabled or
    disabled?
    
    i.e. if "raw IPX" is disabled, a raw IPX Ethernet host cannot talk to an
    FDDI host but can still talk across an FDDI backbone to another raw IPX
    Ethernet host?
    
    Thanks
    Jeannie
2567.3NETCAD::MILLBRANDTanswer mamThu Dec 07 1995 12:554
Krishna has left the company.  You might try asking your question 
in the FDDI conference.

	Dotsie
2567.4NETCAD::B_CRONINFri Dec 08 1995 21:277
    
    Yes, Raw IPX will be fine across the two bridges. 
    
    If a station on the FDDI is cobbled together to see the raw IPX,
    it could talk back, but there are no standard IPX over FDDI
    applications
    that do this.