Advertising none portable Address Space to 2 ISP's

[NetEng631]

Hey Everyone,

I have a question for anyone doing routing at an ISP. As far as I know from working at an ISP in the past, you need portable IP address space either from ARIN or from an ISP to be able to advertise multiple paths on the Internet. Both your ISP also has to not Tag the route as No Export and not filter smaller networks out anything smaller then a /22. I think that it use to be /22 wa the smallest block exported bu ti think that has changed to a /24

Could someone with real knowledge fill me in on this or direct me to a web site that details this. Also if I am missing something on this please let me know.

Thanks

 

[Routerboy]

Non-portable IP space is generally the norm for customers obtaining it from an ISP. Non-portable means just that. It is IP space owned by the ISP which is leased to a customer for a set duration. That IP space should not be advertised by another ISP. As I have seen in the past this does happen sometimes! If you want to have 2 ISPs advertise your space the best thing to do is goto ARIN and get a block bigger than or equal to a /24 as this is the smallest block that will be advertised by your ISP.

Routerboy!

 

[NetEng631]

Thanks for the confirmation. It's just I have seen so many posts ignoring this issue that I taught I was missing something.