Messages cités pour référence (si rien alors fin de message) : Le
31/01/2014 16:59, Fernando Gont a écrit :
On 01/31/2014 12:26 PM, Alexandru Petrescu wrote:
And it's not just the NC. There are implementations that do not limit
the number of addresses they configure, that do not limit the number of
entries in the routing table, etc.
There are some different needs with this limitation.
It's good to rate-limit a protocol exchange (to avoid dDoS), it's good
to limit the size of the buffers (to avoid buffer overflows), but it may
be arguable whether to limit the dynamic sizes of the instantiated data
structures, especially when facing requirements of scalability - they'd
rather be virtually infinite, like in virtual memory.
This means that the underlying hard limit will hit you in the back.
You should enforce limits that at the very least keeps the system usable.
At the end of the day, at the very least you want to be able to ssh to it.
This is not a problem of implementation, it is a problem of unspoken
assumption that the subnet prefix is always 64.
Do you know what they say assumptions? -- "It's the mother of all f* ups".
It's as straightforward as this: whenever you're coding something,
enforce limits. And set it to a sane default. And allow the admin to
override it when necessary.
It is unspoken because
it is little required (almost none) by RFCs. Similarly as when the
router of the link is always the .1.
That's about sloppy programming.
Train yourself to do the right thing. I do. When I code, I always
enforce limits. If anything, just pick one, and then tune it.
Speaking of scalability - is there any link layer (e.g. Ethernet) that
supports 2^64 nodes in the same link? Any deployed such link? I doubt so.
Scan Google's IPv6 address space, and you'll find one. (scan6 of
<http://www.si6networks.com/tools/ipv6toolkit> is your friend :-) )
Do you think they have somewhere one single link on which 2^64 nodes
connect simultaneously? (2^64 is a relatively large number, larger than
the current Internet).
Or is it some fake reply?
Alex
