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Re: v6 multihoming and route filters
Le 06-07-04 à 16:59, Iljitsch van Beijnum a écrit :
On 4-jul-2006, at 13:48, Marc Blanchet wrote:
And again, b) is what I'm proposing since the first (personal)
version of the draft:
- filter/do not advertise any prefix longer than /48.
If we agree on this (filter/do not advertise any prefix longer
than /48), than I'll put it back into the draft!
What would be the purpose of filtering at /48?
- simple: through out anything longer: so /64, /56 will be filtered.
end of it.
That allows for 2^45 = 351 trillion prefixes in the routing table,
which I suspect won't work too well on current routers. And it only
takes a handful of /32s deaggregated into /48s to inflate the IPv6
global routing table to a size larger than the current IPv4 routing
table.
the fact that I'm suggesting to filter at the /48 level is just that
I don't know how to build a concensus right now on another more
restrictive boundary. for the global routing table perspective, I
would love to recommend /32 or smaller, but I'm not sure we can get
that agreement.
have you read the first version of the draft (draft-blanchet-v6ops-
ipv6-routing-guidelines-00.txt?
So filtering at /48 really doesn't buy you anything,
yes, see above: filtering any /56 or /64 or /127 or ...
Is my point clearer?
Marc.
either you don't care and/or you have large routers and then
prefixes longer than /48 won't make much of a difference, or you
care and/or you have small routers and then /48 is too much already.
And in theory, anycast addresses should be announced into inter-
domain routing (when the anycast group spans ASes) as /128s... Or
maybe that one has been removed in an update of the RFC in
question, not sure.
By the way:
mysql> select count(*) from addrspace where type='ipv6' and num > 35;
+----------+
| count(*) |
+----------+
| 137 |
+----------+
mysql> select country, descr as prefix, num as pfxlen from
addrspace where type='ipv6' and num > 35 and not descr like
"2001:7f8:%" and not descr like "2001:504:%" and not descr like
"2001:503:%";
+---------+------------------+--------+
| country | prefix | pfxlen |
+---------+------------------+--------+
| JP | 2001:7fa:: | 64 |
| HK | 2001:7fa:0:1:: | 64 |
| KR | 2001:7fa:0:2:: | 64 |
| JP | 2001:7fa:0:3:: | 64 |
| TW | 2001:7fa:1:: | 48 |
| ID | 2001:7fa:2:: | 48 |
| NZ | 2001:7fa:3:: | 48 |
| NZ | 2001:7fa:4:: | 48 |
| CN | 2001:7fa:5:: | 48 |
| VN | 2001:7fa:6:: | 48 |
| JP | 2001:7fa:7:: | 48 |
| KR | 2001:7fa:8:: | 48 |
| AU | 2001:7fa:9:: | 48 |
| AU | 2001:7fa:a:: | 48 |
| AU | 2001:7fa:b:: | 48 |
| AU | 2001:7fa:c:: | 48 |
| AU | 2001:7fa:d:: | 48 |
| AU | 2001:7fa:e:: | 48 |
| ID | 2001:7fa:f:: | 48 |
| CN | 2001:7fa:10:: | 48 |
| US | 2001:500:: | 48 |
| US | 2001:500:1:: | 48 |
| US | 2001:500:2:: | 48 |
| US | 2001:500:3:: | 48 |
| US | 2001:500:4:: | 48 |
| US | 2001:502:100e:: | 48 |
| US | 2001:502:2eda:: | 48 |
| US | 2001:502:4612:: | 48 |
| US | 2001:502:7a71:: | 48 |
| US | 2001:502:ad09:: | 48 |
| US | 2001:502:cfb5:: | 48 |
| US | 2001:502:d399:: | 48 |
| US | 2001:502:f3ff:: | 48 |
| BR | 2001:12f8:: | 48 |
| AR | 2001:12f8:1:: | 48 |
| CO | 2001:12f8:2:: | 48 |
| MX | 2001:12f8:4000:: | 48 |
+---------+------------------+--------+
37 rows in set (0.16 sec)
=========
IPv6 book: Migrating to IPv6, Wiley, 2006. http://www.ipv6book.ca
Mine is published by Apress, see http://www.runningipv6.net/ :-)
=========
IPv6 book: Migrating to IPv6, Wiley, 2006. http://www.ipv6book.ca