What is the ip range I should order for my internet connection

dan_track · ‎12-09-2009

Hi,

I've asked someone here what range of ip's should I order for my new internet connection. I'm looking for PI ip's so I can do full bgp peering with two ISP's. I'm based in the UK so RIPE is our assigner.

So far I've been told that to do full bgp peering with two different ISP's I need to order a /24 range as that is the lowest range at which BGP can summarise on the internet. Is that true? What will happen if I get less that that e.g /25 or /27 etc..

Thanks

Dan

Jon Marshall · ‎12-09-2009

dan_track wrote:

Hi,

I've asked someone here what range of ip's should I order for my new internet connection. I'm looking for PI ip's so I can do full bgp peering with two ISP's. I'm based in the UK so RIPE is our assigner.

So far I've been told that to do full bgp peering with two different ISP's I need to order a /24 range as that is the lowest range at which BGP can summarise on the internet. Is that true? What will happen if I get less that that e.g /25 or /27 etc..

Thanks

Dan

It's best to check with your ISPs what they will advertise. If you got less than a /24 then the ISPs would not advertise your range although it needs checking as i say.

Provider independant addressing is very useful with dual connections to different ISPs but best to talk to them about what they will and won't do.

Jon

Giuseppe Larosa · ‎12-09-2009

Hello Dan,

for true eBGP multihoming you need a public AS number, then an IP address block is associated to your ASN.

by the way a true eBGP multihoming is probably required to confirm public ASN assignment (this was true years ago before 4 bytes ASN have been introduced)

it is true that mininum prefix advertisable on the internet is /24

see

http://www.ripe.net/ripe/docs/ripe-484.html

this is the current IPv4 assigment policy at RIPE RIR.

>> The minimum size of a sub-allocation is /24. This is the smallest prefix length that can be reverse delegated and allows for a reasonable number of small assignments to be made by a downstream network operator.

There is some burocracy and you need to fill some application forms.

Hope to help

Giuseppe