The MPLS WG Archive

[Randy Bush <randy@psg.com>]

and which one will work for a large isp with lots of vpn customers and lots
of connections to other peer isps?

> the answer is no. There are various ways to design Internet connectivity
> within this environment, one of which is to carry full Internet routes on
> the PE router. Other options include default routing from VPN sites to a
> central site that has Internet connectivity, another is to offload the
> Internet routes from the PE and run direct eBGP sessions from the VPN site
> to the Internet exit point. Which option is actually taken will depend on
> the specific design requirements. Jim
> 
> At 08:37 26/10/2000 -0400, Barry Hass wrote:
> >Eric,
> >
> >Doesn't a PE router have to handle the full Internet routing
> >table, plus VRFs for whatever VPNs it is supporting? I think
> >that what some folks are suggesting is that BGP (not "the box",
> >but BGP specifically) is already bumping up against scaling
> >limits at 100,000 or so routes, and that burdening it with the
> >additional responsibility of managing VPNs is not such a great
> >idea. ("Some folks" please correct me if I'm wrong). Can you
> >comment on that?
> >
> >By the way, I don't have enough information to have an opinion
> >on this. I'm just trying to steer the discussion back to what
> >I thought was an interesting technical question before the
> >insults started to fly.
> >
> >> In the  NBVPN routing environment, it is  not true that 
> >> anyone  in the world
> >> needs to be  able to reach anyone else  in the world.  Each 
> >> VPN  has its own
> >> inter-connectivity  matrix,  much  smaller  than the  
> >> Internet  connectivity
> >> matrix.  Now if you add up all the VPN routes, summed over 
> >> all VPNs, you may
> >> indeed get  a much larger  number than the  number of 
> >> Internet  routes.  But
> >> there is no one box which needs  to hold them all.  Since an 
> >> instance of BGP
> >> runs in a particular box, and only  has to deal with the 
> >> routes that need to
> >> be in that box,  you don't run up against the same  box 
> >> scaling problems you
> >> run up  against in  the Internet routing  environment.  You 
> >> can  design your
> >> system to  have a given box  handle as many routes  or as few 
> >>  routes as you
> >> want.  
> > 
> 
> 
> Jim Guichard CCIE #2069
> Network Design Consultant EMEA
> Global Solutions Engineering 
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