[c-nsp] Growing BGP tables

[Rodney Dunn]

It's not that simple.

BGP (as does other routing protocols) present
their routes to the RIB.  The RIB doesn't drive
update processing.  Just like the FIB doesn't
drive what gets populated in the RIB.  There
isn't a backwards notification mechanism available
to do that that I'm aware of.

I'll see if we can come up with something and let
you know.

Rodney


On Tue, Nov 23, 2004 at 08:16:27AM +1000, David J. Hughes wrote:
> 
> Hey Rodney,
> 
> How about ...
> 
> for each prefix received in update
>    for each more specific prefix in RIB
>      if RIB prefix ge /24 and same next hop as update prefix
>        drop RIB prefix
>    if update prefix ge /24
>      for each less specific prefix in RIB
>        if RIB next hop same as update next hop
>          drop update prefix
> 
> something like that would filter during the update and wouldn't require 
> another full copy of the table to be held.  I'm sure you guys could 
> come up with something more efficient but the basic idea would work 
> wouldn't it?
> 
> 
> David
> ...
> 
> 
> On 23/11/2004, at 7:59 AM, Rodney Dunn wrote:
> 
> > I don't see how you can do it without holding
> > a full copy of all updates because you are
> > making a decision for one update based on
> > matches of all other updates which is
> > back to storing a shadow copy.