On Sun, Mar 13, 2011 at 3:42 PM, Christopher Morrow <morrowc.lists@gmail.com> wrote:
not everyone drinks the mpls koolaide... so it's not always 'just a label switch' and depending upon how large your PE mesh is, there are
If it isn't just a label switch, then features can (and sometimes do) drive upgrades (therefore costs.)
not need that info, but the edge likely does, yes? Have 100g customers today? planning on having them in the next ~8/12/18 months?
If you did your purchasing the way Bill Herrin suggests, you'd buy a box with 100GbE ports for a POP or branch that is not projected to have 100GbE customers, just because it's the biggest box. His position is that man-power to do an upgrade is always more costly than capital dollars for the actual equipment, and ignores the fact that the biggest box is by no means guaranteed to offer new *features* which may be required. I think most of your post is responding to a mis-read of my post, so I'll skip back to the FIB size question at hand:
sometimes... sometimes it's just business. I suppose the point here is that a box doesn't live ~12 months or even 24, it lives longer. Planning that horizon today is problematic when a box today (even the largest box) tops out just north of 2m routes (v4, I forget the mix v4/6 numbers). your network design may permit you to side step that issue in places, but planning for that number is painful today.
I'm not comfortable making the generalization that buying the box with the largest available FIB is always the most cost-effective choice. In some "box roles," traffic growth drives upgrades, and increased FIB size in future boxes will be one advantage of a future upgrade that also increases port speed or density. In other "box roles," features drive upgrades, and again, FIB size may increase in future boxes which will be bought anyway to gain desired features. It's foolish and overly-simplistic to assume that every box upgrade will be driven by an eventual exhaustion of FIB capacity. Currently, FIB capacity is being driven by the needs of service providers' VPN PE boxes. This is great for networks that do not have that need, because it is driving FIB capacity up (or cost down) and further reducing the chance that FIB exhaustion will trigger an upgrade before other factors, such as port speed/density/features. -- Jeff S Wheeler <jsw@inconcepts.biz> Sr Network Operator / Innovative Network Concepts