Re: FW: /8s and filtering

[bmanning () vacation karoshi com]

> Hello,
>  No, this is not the case. I enquired and it seems multihoming is not a
> justification for a /24 in any RIR.
>
>  Does a network have to be able to fully utilize a /26 (25% of /24) in
> order to multihome?
>
> Harsha.

        You do err, not knowing the scripture.

        To multihome, you need to get (at least) two other providers to listen
        to your routing announcement(s).  Wango'z'tango! multihoming done.
        Your announcement can be as small as a /32 (although there was a
        time when at least one /33 was delegated...)
        
        What's that?  you want everyone running IP to reach your gopher
        server?  Tough luck.  then you must somehow meet/pass the  
        byzantine filtering rules (unpublished sometimes) that parties 
        which are three and four hops away from your edge will impose on 
        whatever announcements you happen to propogate.  The dead hand of 
        the CIDR mafia will eat your lunch and you'll have no recourse.

        So, whats a poor'lil player todo?  Some say that this works:

                ) build a rich peering mesh. (reduces your dependence
                  on any one transit provider)
                ) buy transit (where you -MUST-) and insist that you
                  understand BGP, peering, and how to prevent leakage.
                  Demand that they accept your announcement(s). 
                  [ note that this may turn transit into peering, which
                    may trigger other unpleasent SOPs from the salesdroids
                    but hey, multihoming is -worth- the effort...]

        as usual, YMMV.

--bill (who is earning the sobriquet "grumpy" today)