Hello, Currently APNIC's policy means that if an organization can fully use a /26 (since 25% of /24=/26 and to satisfy the multihoming requirement the organization will need to have a prefix advertised by two or more ISPs) it can get a multihoming assignment from APNIC. If Class C /8s are over and ISPs maintain their filtering policies, the bar would be raised to fully using a /24 instead (since 25% of /22 = /24 and filtering in Class A is done at /22). 8 of the 9 APNIC /8s are from the Class C space. Only one is from the Class A space. However there are only three untouched /8s left in the Class C space - 197/8, 222/8, 223/8. Actually, I wanted to know if the filtering policies will change to accommodate this - i.e. will /24s be allowed in the Class A space? I was also curious about this - if I am a customer who wants to multihome and can justify only a /24, I would go to an ISP which has an allocation from the Class C space rather than one from the Class A space. Do ISPs get to choose where the allocation comes from? Harsha.
I was also curious about this - if I am a customer who wants to multihome and can justify only a /24, I would go to an ISP which has an allocation from the Class C space rather than one from the Class A space.
It doesn't matter. For all practical purposes, basement multihomers only care that their two or three providers have their route.
Do ISPs get to choose where the allocation comes from?
Ask your ISP if they'll let you choose. But it usually doesn't matter, if you can only justify a /24, you'll find about the same filtering policies in both traditional class A space and class C space. But again, it doesn't matter. So long as each of your providers will honor your route (and why wouldn't they, you're paying them to) you shouldn't have a problem. Just pick your most reliable provider, and the one you're pretty sure you're going to stay with the longest, and get your IP space from them. Make sure they don't mind you advertising your block through other providers. And give some thought to hiring a competent consultant to help you. You can hire a consultant even if you are the consultant. In fact, no competent consultant would do otherwise outside his or her area of expertise. Don't learn to multihome at your client's expense. ;) DS
Hello, Currently APNIC's policy means that if an organization can fully use a /26 (since 25% of /24=/26 and to satisfy the multihoming requirement the organization will need to have a prefix advertised by two or more ISPs) it can get a multihoming assignment from APNIC.
If RIRs begin allocating really long prefixes, it would be best if they did it all from a single block. Allowing providers to allow long prefixes only from that block, rather than having to accept /24 willy nilly across the entire address space. Also, just because an RIR is allocating out of former class C does not necessarily mean providers will accept a /24, if the RIR allocation policy is shorter than /24. However, this is not a problem as long as the entity receiving the address space always announces their largest aggregate. It is only a problem when people only announce more-specifics.
participants (3)
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bdragon＠gweep.net -
David Schwartz -
Harsha Narayan