Scalability issues in the Internet routing system

Tue Oct 18 17:41:53 UTC 2005

Andre Oppermann wrote:
> 
> I guess it's time to have a look at the actual scalability issues we
> face in the Internet routing system.  Maybe the area of action becomes
> a bit more clear with such an assessment.
> 
> In the current Internet routing system we face two distinctive scalability
> issues:
> 
> 1. The number of prefixes*paths in the routing table and interdomain
>    routing system (BGP)
> 
> This problem scales with the number of prefixes and available paths
> to a particlar router/network in addition to constant churn in the
> reachablility state.  The required capacity for a routers control
> plane is:
> 
>  capacity = prefix * path * churnfactor / second
> 
> I think it is safe, even with projected AS and IP uptake, to assume
> Moore's law can cope with this.

Moore's law for CPUs is kaput. Really, Moore's Law is more of an 
observation, than a law. We need to stop fixating on Moore's law for the 
love of god.  It doesn't exist in a vacuum, Components don't get on the 
curve for free.  Each generation requires enormously more capital to 
engineer the improved Si process, innovation, process, which only get 
paid for by increasing demand.   If the demand slows down then the 
investment won't be recovered and the cycle will stop, possibly before 
the physics limits, depending on the amount of demand, amount of 
investment required for the next turn etc.

Also, no network I know is on the upgrade path at a velocity that they 
are swapping out components in a 18 month window. Ideally, for an 
economically viable network, you want to be on an upgrade cycle that 
lags Moore's observation. Getting routers off your books is not an 18 
month cycle, it is closer to 48 months or even in some cases 60 months.

Then we have the issue of an memory bandwidth to keep the ever changing 
prefixes updated and synced.

/vijay