NetworkManager[21107]: <info> (bond0): exported as /org/freedesktop/NetworkManager/Devices/6
connection
	id : "bond0" (s)
	uuid : "c6022030-cc6c-4747-b485-96fcacb9cfc9" (s)
	interface-name : "bond0" (s)
	type : "bond" (s)
	permissions :  (sd)
	autoconnect : FALSE (s)
	timestamp : 1404408352 (s)
	read-only : FALSE (sd)
	zone : NULL (sd)
	master : NULL (sd)
	slave-type : NULL (sd)
	secondaries :  (sd)
	gateway-ping-timeout : 0 (sd)


ipv6
	method : "link-local" (s)
	dhcp-hostname : NULL (sd)
	dns :  (s)
	dns-search :  (sd)
	addresses :  (s)
	routes :  (s)
	ignore-auto-routes : FALSE (sd)
	ignore-auto-dns : FALSE (sd)
	never-default : FALSE (sd)
	may-fail : TRUE (sd)
	ip6-privacy : -1 (sd)


ipv4
	method : "auto" (s)
	dns : 192.168.0.2 (s)
	dns-search :  (sd)
	addresses :  (s)
	address-labels :  (sd)
	routes :  (s)
	ignore-auto-routes : FALSE (sd)
	ignore-auto-dns : FALSE (sd)
	dhcp-client-id : NULL (sd)
	dhcp-send-hostname : TRUE (sd)
	dhcp-hostname : NULL (sd)
	never-default : FALSE (sd)
	may-fail : TRUE (sd)


bond
	interface-name : "bond0" (s)
	options : mode=balance-rr,miimon=1 (s)


NetworkManager[21107]: <info> Connection 'bond0' differs from candidate 'Bond connection 1' in bond.options, 802-3-ethernet.s390-options, 802-3-ethernet.cloned-mac-address, 802-3-ethernet.s390-subchannels, 802-3-ethernet.s390-nettype

[dcbw@blah NetworkManager (nm-0-9-10*)]$ nmcli con show "Bond connection 1"
connection.id:                          Bond connection 1
connection.uuid:                        7b651fc5-7c7d-4217-a91b-138bbaf017fe
connection.interface-name:              bond0
connection.type:                        bond
connection.autoconnect:                 no
connection.timestamp:                   1404408346
...
802-3-ethernet.mac-address:             --
802-3-ethernet.cloned-mac-address:      --
802-3-ethernet.mtu:                     auto
802-3-ethernet.s390-subchannels:        
802-3-ethernet.s390-nettype:            --
802-3-ethernet.s390-options:            
bond.interface-name:                    bond0
bond.options:                           miimon=1,updelay=0,downdelay=0,mode=balance-rr


Two problems:

1) The candidate has an 802-3-ethernet connection, but the generated connection does not.  If the candidate NMSettingWired is all defaults, then the candidate can match the generated connection.

2) bond.options doesn't match; the generated connection has updelay and downdelay options that were read from sysfs, but the candidate connection doesn't have those options because they are the default values.  If either connection has default bond options we should just ignore those when matching.