Conference turris::digital_unix

9340.0. "load balancing, failover, gated (again)" by MEOC02::MCCOY (want peace ? -> work for justice) Tue Apr 01 1997 05:42

    Load Balancing & failover again.
    
    note 6869 offers some advice, but the information is not complete.  For
    example, how and in which box are "half the routes" defined for each of the
    two routers described?
    
    My environment
    
    Digital	Digital
    Unix #1	Unix #2
      |		  |
      |		  |
    ===================
      |		  |
      |		  |
    cisco	cisco
    rtr #1	rtr #2
      |		  |
      |	 2mbps	  |
      |	 links	  |
      |		  |
    ISP	      	ISP      
     == INTERNET ==
    
    For the Digital Unix boxes I want
    A	load balancing (or something close)
    B   failover from rtr to rtr
    C	the ability to set routing weights on Digital Unix systems (IE rtr1
    gives better routes than rtr2, etc)
    
    For A & B, I thought that gated + OSPF would provide a solution as I
    know on cisco that OSPF will support path splitting/load sharing. 
    Having configured gated for OSPF, I discovered that the Digital Unix 
    kernel is apparently unable to support the notion of multiple routes to
    a single destination.   Scratch true load balancing.  
    
    I then re-read the gated documentation and discovered an option command
    "gendefault" which will create a default route in the kernel, but only
    with when EGP or BGP is used as the routing protocol.
         
    So, I think the solution is to use the gendefault (with preference
    clause) with one Unix system with primary prefence pointing to cisco #1
    (secondary prefence to cisco #2) and the other vice-versa, and enable
    BGP4 on the cisco.
    
    Has anyone tried this, or come up with a better solution to the
    problem?  Any sample configs for BGP4/gated would be really appreciated.
    
    cisco also support a "distance" command, which allows incoming routes
    to be arbitrarily weighted.  Is there anything equivalent for gated or
    elsewhere in Digital Unix?  I can't see it in the docs....
    
    Finally, which version(s) of gated is/are in Digital Unix 4.0/a/b ?
    
    thanks
    
    andrew mccoy
    NSIS, Melbourne, Australia.