Why don't ISPs peer with everyone?

[hank at efes.iucc.ac.il (Hank Nussbacher)]

On Mon, 6 Jun 2011, rucasbrown at hushmail.com wrote:

Please define ISP.

-Hank

> Hello,
>
> I wouldn't consider myself a network engineer, nor do I have any
> formal training, but why don't ISPs peer with every other ISP? It
> would only save EVERYONE money if they did this, no? Only issue I
> see is with possibly hijacked / malicious AS owners, but that's not
> very common to do without being caught.
>
> All the whole "don't peer with this guy" only makes your customers
> have worse latencies and paths to other people, making the Internet
> less healthy.
>
> Thanks,
> Rucas
>
> PS: sorry if I sent this twice; client lagged a bit.
>
>