Single router for P/PE functions

Mikael Abrahamsson swmike at
Fri Sep 4 04:14:52 UTC 2009

On Thu, 3 Sep 2009, Serge Vautour wrote:

> I'm pretty confident that a router can be used to perform P & PE 
> functions simultaneously. What about from a best practice perspective? 
> Is this something that should be completely avoided? Why? We're 
> considering doing this as a temporary workaround but we all know 
> temporary usually lasts a long time. I'd like to know what kind of mess 
> awaits if we let this one go.

Collapsing P/PE functions certainly saves CAPEX, the downside is that you 
might need to reload your PE (affecting customers) due to a core feature 
upgrade or bug fix, or the other way around. With separate P and PE 
functions and PEs being dual attached to two Ps, you can reboot P layer 
with minimal end customer impact.

I'd imagine that in smaller networks it makes more sense to collapse 
compared to larger network, because a smaller network has fewer customers 
to be affected by each router problem.

It's basically "put all the eggs in one basket" kind of issue, it's easier 
to carry around but you lose more when something happens.

Mikael Abrahamsson    email: swmike at

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