Subject: RE: [dhcwg] Failover: poolreq message secondary-only?

From: "steve" <[email-masked]>
Date: Fri, 2 Nov 2001 16:57:39 -0500

Yes!!!

I have been advocating something similar a while back.

IMHO primary / backup ownership of addresses should be distinct from lease
state, and ownership transfer requests should be symmetrical.

Leases should belong to either the primary or the backup,
regardless of their status ( free, active, abandoned...).

This would be conceptually much cleaner.

Ownership transfer should be an explicit transaction.
The way it is today, it is implicit, when the lease gets given out,
because the lease ownership is mixed in with the life cycle states.

I failed to convince the rest of the failover gang, and finally
given up...perhaps you will have more luck.

/sG

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]On Behalf Of Ted
Lemon
Sent: Thursday, November 01, 2001 7:49 PM
To: [email-masked]
Subject: [dhcwg] Failover: poolreq message secondary-only?

The failover protocol draft says that only the secondary can send a poolreq
message, and indicates that the primary should attempt to reclaim backup
leases from the secondary by updating from backup to free.   This seems
strange to me.   Wouldn't it make more sense that whichever peer notices
that it is short on leases would send a poolreq to the other peer, and the
other would, if possible, send some leases out of its free pool?   The
advantage of doing it this way is that we don't have to worry about
conflict resolution - the secondary knows which leases it's assigned, so it
can just send what it wants to send to the primary.

I guess either way works - it just seems cleaner to make poolreq/poolresp
work symmetrically.

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---

From: Ted Lemon <[email-masked]>
Date: Fri, 2 Nov 2001 15:31:56 -0700

> This would be conceptually much cleaner.

Good heavens, that wasn't what I was proposing at all.   That would require 
a complete rewrite of the spec, which is out of the question.   I'm just 
asking for the restriction that only the secondary can send poolreq, and 
the primary send poolresp, be removed.

---

From: "steve" <[email-masked]>
Date: Fri, 2 Nov 2001 18:22:31 -0500

Given what we have, leases flow to the primary, as they get assigned.

What you propose would allow the primary to reclaim some of the un-used
backup
pool during normal operation.

I believe the current protocol already allows for this during
synchronization.
After the primary received all updates from the secondary, it can safely set
the status of any "backup" lease to "free", because the backup is not
running
until the synchronization is complete.

All said, what you propose is useful and worth doing.

/sg