Comment by AtlasBarfed
1 day ago
Setting aside the address scarcity issue, how is IPv6 going to simplify the routing table? If anything, it would just be an explosion of the number of addresses?
I mean a million is objectively a large number if it's all on paper, but to me, that's not a particularly large data set for talking about the entire freaking internet.
And how cheap of a SOC can handle that in memory? A better question might be to even make a system on a chip that couldn't handle that memory?
The small ISP that serves my home has six IPv4 prefixes and one IPv6 prefix.
My small hosting provider has I think 7 v4 prefixes, but could be one v6 prefix. Maybe not --- a lot of their /22s are advertised as four /24s to allow for a DDoS Mitigation provider to attract traffic when needed; but it'd probably still be fewer prefixes with v6.
Not every ASN looks the same, but many of them would advertise a lot fewer prefixes if they could get contiguous addresses, but it's not possible/reasonable to get contiguous allocations for v4.
Since the routing table is organized around prefixes, if there is complete migration, the routing table will probably be smaller.
A single /32 IPv6 prefix is actually easier on the router (computational and memory wise) than a dozen /24 IPv4 prefixes.
Huh A single prefix is easier on the router than a dozen.. I should hope so? Isn’t this kind of like saying the grade 1 math test is easier than the grade 12 math test ?
It's not just any memory. When it comes to core infrastructure routers those routes need to fit into specialized and expensive CAM (Content Addressable Memory) to do the lookups in hardware. And on every single one.
Right but that's still not really answering his question. Sure, the constant factor is higher for router TCAM memory. Still: you can sum this post up as "in the late 1990s, tier-1 carriers filtered advertisements for all but the 'swamp' range down to /19s or smaller prefixes; now everything is the 'swamp'". Why is that?
The issue is; in the default free zone, every peer which gives you a full table, gives you 1 million routes. Core infrastructure is not getting refreshed every 5 year, I have heard so...
There theory might be that an organisation would end up advertising a single prefix, rather than whatever they have now (say 40 networks with various prefixes).