Conference 7.286::fddi

2108.0. "FDDI transparency to SRB Token Ring traffic" by LFOIS1::MOUSSU (so unusuaL terM) Fri Aug 09 1996 06:38

  [ cross-posted in FDDI and CISCO notesfiles ]
  
  We have a large bank here planning a metropolitan network between 8 to 10 
  locations in the Paris area. 
  Unless more details needed, much significant facts are:
  - beside other minor needs, each location is mainly a Token Ring based LAN: 
  the outgoing device is an existing Cisco 4500 router that we would connect 
  to a concentrator included in a ring crossing both GSW/FDDIs.
  - Data traffics are  NETbeui, IP and SNA/LLC2.
  
  In summary we will build an FDDI MAN interconnecting several CISCO routers.
  
  The customer has been worried about some limitations the solution would 
  bring concerning the FDDI transparency to SR bridging for Token Ring frames.
  In my understanding, the main concern is about the way that Cisco routers 
  convert TR frames to FDDI format and vice-versa.
  I guess there is no problem about pure IP (routed) traffic but the question 
  is about NETbeui and SNA/LLC2 traffic where transparent translation would 
  suppress the SR information.
  
  In the present situation they're linked thru E1 lines and all goes well. Is 
  there a difference if we use an FDDI datalink:
  - does that imply that we should use a "neutral" intermediate protocol, eg. 
  encapsulate or tunnel all non-IP frames into IP (RSRB ?) In such a case 
  they're concerned with the performance side. 
  - Are there other alternatives with less performance drawback ?
  - More, would enabling spanning tree on the GSW/FDDI have an effect or not ?
   
  Thanks for helping
  Laurent
  

Encapsulating the non-rotable traffic in IP is probably your best bet.

I doubt very much if the Cisco box would even forward the TR traffic with or
without source routing info. I'm not aware of any vendor that supports source
routing on FDDI.

-tom

>>I doubt very much if the Cisco box would even forward the TR traffic with or
>>without source routing info. I'm not aware of any vendor that supports source
>>routing on FDDI.
    
    Uh, actually, we do.  :-)  Novell supports source routing over both
    Token Ring and FDDI and our NetWare ODI drivers for DEFEA and DEFPA
    support it.

    I can't say whether or not our FDDI bridges support it, but our FDDI
    concentrators do (not that there's much them to do with regards to
    source routing).
    
    - Larry

Ok, I stand corrected. I still doubt very much that our bridge products support
source-routing but the question asked in .0 concerns cisco brouters so it's
moot.

There used to be a cisco-related notesfile. A question there might be
appropriate.

-tom

    The DEC Bridges do not support source routing.