more specific routes in today reality

Comments followed.

> 
> Hi,
> 
> On Tue, Oct 09, 2001 at 09:13:05PM +0200, Jan-Ahrent-Czmok wrote:
> > Some providers are multihomed
> > but cannot cover the costs, even for a small lir.
> 
> If you want to be multihomed, the costs for routers & co. are 
> far higher
> than for being LIR.  If you can't afford being LIR, be single-homed.
> 

Great! Now we have to collect routing policies from thousands of small LIRs
while still
have to deal with thousands of small prefixes.


> 
> Nonsense.  Nobody is announcing 192.0.0.0/8, or supernets of other's
> networks - and what is in the RIPE database doesn't affect routing.
> 
> To show the first few things from 192/8:
> 
> *>i192.0.32.0       195.158.244.133               100      0 
> 1755 1239 5676 226
> i
> *>i192.0.34.0       195.158.244.133               100      0 
> 1755 1239 5676 226
> i
> * i192.0.36.0       195.206.66.61            3    100      0 
> 3300 701 2914 20144
>  i
> *>i                 195.158.244.133               100      0 
> 1755 1239 2914 2014
> 4 i
> * i192.1.0.0/16     195.206.66.61            3    100      0 
> 3300 701 1 i
> *>i                 195.158.244.133               100      0 
> 1755 1239 1 i
> * i192.2.0.0/16     195.206.66.61            3    100      0 
> 3300 701 1 i
> *>i                 195.158.244.133               100      0 
> 1755 1239 1 i
> 
> so if I filter those, why should the traffic go to XLink?    
> Why should
> *any* traffic go to RIPE?  It will be just blackholed (or 
> default-routed
> to one of my upstreams, if I happen to have a default-route).
> 
> Please do your homework about routing and BGP before selling people 
> consulting about multihoming.
> 

Now more and more major ISPs are filtering out routes from other ISPs (
becuase we don't have
transit agreements) so the multi-homed customer have to have their own AS.

And if the major ISPs stop listening to the more specfic routes then even
using the address from PI space won't work (unless you are big enough).

All these solutions kind of imply that if you can't have /20 prefix then you
can't be multi-homed. What happen if a customer want to have an OC-48
multi-homed link but only use prefix < /20 (that happens to the Internet
Exchange people a lot ) ? 


Ping Lu
Cable & Wireless USA
Network Tools and Analysis Group
W: +1-703-292-2359
E: plu at cw.net