Forum Linux.debian/ubuntu Paquets RX "dropped" sur interface en mode "bonding"

Bonjour,

Je viens de mettre en place un bonding de deux interfaces sur un serveur connecté à un switch Cisco en mode 802.3ad sous Debian Wheezy 7.1 (noyau 3.2.46 amd64).
Les cartes réseau sont des cartes Gigabit Intel I350.

Problème : ifconfig (et les outils de monitoring SNMP) fait apparaître de nombreux paquets RX en statut "dropped", ce qui de mon point de vue n'est pas normal (mais je suis loin d'être un pro en réseau !).

Pour info, voici quelques extraits de mes fichiers de configuration :

/etc/modules

  loop
  bonding
  mii

/etc/network/interfaces

  auto eth2
    iface eth2 inet manual
    bond-master bond0

  auto eth3
    iface eth3 inet manual
    bond-master bond0

  auto bond0
    iface bond0 inet static
    address 172.23.12.170
    netmask 255.255.255.0
    network 172.23.12.0
    broadcast 172.23.12.255
    gateway 172.23.12.1
    bond-mode 802.3ad
    bond-miimon 100
    bond-downdelay 200
    bond-updelay 200
    bond-lacp-rate 4
    bond-slaves none
    # dns-* options are implemented by the resolvconf package, if installed
    dns-nameservers 172.23.8.10 172.23.8.11
    dns-search mondomaine.fr

/proc/net/bonding/bond0

  Bonding Mode: IEEE 802.3ad Dynamic link aggregation
  Transmit Hash Policy: layer2 (0)
  MII Status: up
  MII Polling Interval (ms): 100
  Up Delay (ms): 200
  Down Delay (ms): 200

  802.3ad info
  LACP rate: fast
  Min links: 0
  Aggregator selection policy (ad_select): stable
  Active Aggregator Info:
    Aggregator ID: 1
    Number of ports: 2
    Actor Key: 17
    Partner Key: 308
    Partner Mac Address: 02:00:00:00:00:64

  Slave Interface: eth2
  MII Status: up
  Speed: 1000 Mbps
  Duplex: full
  Link Failure Count: 2
  Permanent HW addr: bc:30:5b:f6:b8:90
  Aggregator ID: 1
  Slave queue ID: 0

  Slave Interface: eth3
  MII Status: up
  Speed: 1000 Mbps
  Duplex: full
  Link Failure Count: 2
  Permanent HW addr: bc:30:5b:f6:b8:92
  Aggregator ID: 1
  Slave queue ID: 0

Sortie de ifconfig :

  bond0   Link encap:Ethernet  HWaddr bc:30:5b:f6:b8:90  
          inet adr:172.23.12.170  Bcast:172.23.12.255  Masque:255.255.255.0
          adr inet6: fe80::be30:5bff:fef6:b890/64 Scope:Lien
          UP BROADCAST RUNNING MASTER MULTICAST  MTU:1500  Metric:1
          RX packets:2590496 errors:0 dropped:933932 overruns:0 frame:0
          TX packets:878665 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 lg file transmission:0 
          RX bytes:301150114 (287.1 MiB)  TX bytes:139621158 (133.1 MiB)

  eth2    Link encap:Ethernet  HWaddr bc:30:5b:f6:b8:90  
          UP BROADCAST RUNNING SLAVE MULTICAST  MTU:1500  Metric:1
          RX packets:1010041 errors:0 dropped:8 overruns:0 frame:0
          TX packets:862494 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 lg file transmission:1000 
          RX bytes:97240781 (92.7 MiB)  TX bytes:137448366 (131.0 MiB)

  eth3    Link encap:Ethernet  HWaddr bc:30:5b:f6:b8:90  
          UP BROADCAST RUNNING SLAVE MULTICAST  MTU:1500  Metric:1
          RX packets:1580455 errors:0 dropped:11 overruns:0 frame:0
          TX packets:16171 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 lg file transmission:1000 
          RX bytes:203909333 (194.4 MiB)  TX bytes:2172792 (2.0 MiB)

  lo      Link encap:Boucle locale  
          inet adr:127.0.0.1  Masque:255.0.0.0
          adr inet6: ::1/128 Scope:Hôte
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:17 errors:0 dropped:0 overruns:0 frame:0
          TX packets:17 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 lg file transmission:0 
          RX bytes:2572 (2.5 KiB)  TX bytes:2572 (2.5 KiB)

Extrait de dmesg:

[    9.260649] bonding: Ethernet Channel Bonding Driver: v3.7.1 (April 27, 2011)
[    9.260658] bonding: MII link monitoring set to 100 ms
[   11.928070] ADDRCONF(NETDEV_UP): bond0: link is not ready
[   11.931786] bonding: bond0: Adding slave eth2.
[   12.436511] bonding: bond0: enslaving eth2 as a backup interface with a down link.
[   12.467843] bonding: bond0: Adding slave eth3.
[   12.816225] bonding: bond0: enslaving eth3 as a backup interface with a down link.
[   12.842742] bonding: bond0: Setting MII monitoring interval to 100.
[   12.842799] bonding: bond0: Setting down delay to 200.
[   12.842839] bonding: bond0: Setting up delay to 200.
[   12.844405] bonding: unable to update mode of bond0 because interface is up.
[   12.853623] bonding: bond0: Ignoring invalid LACP rate value 4.
[   12.861663] ADDRCONF(NETDEV_UP): bond0: link is not ready
[   15.590369] ixgbe 0000:01:00.0: eth2: NIC Link is Up 1 Gbps, Flow Control: RX
[   15.675747] bonding: bond0: link status up for interface eth2, enabling it in 0 ms.
[   15.675755] bonding: bond0: link status definitely up for interface eth2, 1000 Mbps full duplex.
[   15.677561] ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready
[   16.050053] ixgbe 0000:01:00.1: eth3: NIC Link is Up 1 Gbps, Flow Control: RX
[   16.075469] bonding: bond0: link status up for interface eth3, enabling it in 200 ms.
[   16.275330] bonding: bond0: link status definitely up for interface eth3, 1000 Mbps full duplex.
[   25.980658] bond0: no IPv6 routers present

Une idée ?
Je suis un peu sec sur le sujet, là… :-(

Merci

NdM (neox): correction de la syntaxe markdown pour mise en forme et prise en charge coloration syntaxique