Look at it this way: a dhcp server giving out addresses in a private class b with short lease times (an isp, say), using the hash table will result in MUCH higher performance than a flat, sorted list of available addresses.... It's a scalability thing.
Aubrey Wells wrote: > Hmm i meant to avoid the use of the word "random" in my post as its a > bad word to use in this context. Its not "random" per se, its just non- > deterministic. What that basically means is, you can't really predict > with 100% certainty what ip will be handed out next. There is a pre- > determined order to it (the hash table). What you will see 99% of the > time from ISC dhcpd (in my experience) is at the begining, when there > are 0 leases, the IPs will be handed out in descending order because > that's how the hash table with no entries to exclude gets built. After > there are leases out and ones in the middle expire and are placed back > in to the pool, its is non-deterministic which ip will get handed out > next. It could be the next one in descending order, it could be the > highest one of the ones just expired, it could be the oldest one > expired, or it could be one in the middle of the expired list. It all > depends on what the IPs that are available are and in what order they > expire/rejoin the pool. This is further complicated by the fact that a > client will ask for the ip that it knows it last leased, and if it is > currently unused (even if the lease is expired) the server will assign > it to that host. You can do some experiments with this by deleting > entries from the /var/lib/dhcp/dhcpd.leases (might be in a different > place on vyatta/debian) file to manually expire/delete leases. > > I didn't mean to imply that I think you're stupid, I was really asking > why it is such an issue. For some one to not use a product because it > assigns addresses in descending rather than ascending order is odd > IMHO and I figured there was some weird requirement. > > ------------------ > Aubrey Wells > Senior Engineer > Shelton | Johns Technology Group > A Vyatta Ready Partner > www.sheltonjohns.com _______________________________________________ Vyatta-users mailing list Vyatta-users@mailman.vyatta.com http://mailman.vyatta.com/mailman/listinfo/vyatta-users
