bonded active-backup ethernet-wifi drops packets

["Brian J. Murrell" <brian@interlinx.bc.ca>]

[-- Attachment #1: Type: text/plain, Size: 2719 bytes --]

Hi.

I have an active-backup bonded connection on a 5.1.6 kernel where the
slaves are an Ethernet interface and a wifi interface.  The goal is to
have network transparent (i.e. same and IP address on both interfaces)
interface which takes advantage of high-speed and low-latency when it
can be physically plugged into the wired network but have portability
when unplugged through WiFi.

It all works, mostly.  :-/

I find that even when the primary interface, being the Ethernet
interface is plugged in and active, the bonded interface will drop
packets periodically.

If I down the bonded interface and plumb the Ethernet interface
directly, not as a slave of the bonded interface, no such packet
dropping occurs.

My measure of packet dropping, is by observing the output of "sudo ping
-f <ip_address>.  In less than a few minutes even, on the bonded
interface, even with the Ethernet interface as the active slave, I will
have a long string of dots indicating pings that were never
replied.  On the unbonded Ethernet interface, no dots, even when
measured over many days.

My bonding config:

$ cat /proc/net/bonding/bond0
Ethernet Channel Bonding Driver: v3.7.1 (April 27, 2011)

Bonding Mode: fault-tolerance (active-backup)
Primary Slave: enp0s31f6 (primary_reselect always)
Currently Active Slave: enp0s31f6
MII Status: up
MII Polling Interval (ms): 100
Up Delay (ms): 0
Down Delay (ms): 0

Slave Interface: enp0s31f6
MII Status: up
Speed: 1000 Mbps
Duplex: full
Link Failure Count: 0
Permanent HW addr: 0c:54:15:4a:b2:0d
Slave queue ID: 0

Slave Interface: wlp2s0
MII Status: up
Speed: Unknown
Duplex: Unknown
Link Failure Count: 1
Permanent HW addr: 0c:54:15:4a:b2:0d
Slave queue ID: 0

Current interface config/stats:

$ ifconfig bond0
bond0: flags=5187<UP,BROADCAST,RUNNING,MASTER,MULTICAST>  mtu 1500
        inet 10.75.22.245  netmask 255.255.255.0  broadcast 10.75.22.255
        inet6 fe80::ee66:b8c9:d55:a28f  prefixlen 64  scopeid 0x20<link>
        inet6 2001:123:ab:123:d36d:5e5d:acc8:e9bc  prefixlen 64  scopeid 0x0<global>
        ether 0c:54:15:4a:b2:0d  txqueuelen 1000  (Ethernet)
        RX packets 1596206  bytes 165221404 (157.5 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 1590552  bytes 162689350 (155.1 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

Devices:
00:1f.6 Ethernet controller: Intel Corporation Ethernet Connection (2) I219-LM (rev 31)
02:00.0 Network controller: Intel Corporation Wireless 8265 / 8275 (rev 78)

Happy to provide any other useful information.

Any ideas why the dropping, only when using the bonded interface?

Cheers,
b.



[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 488 bytes --]