LACP Failing to TP Link SG3424 Switch

relmes

I'm trying to set up a LACP LAG between pfsense and a TP-LINK SG3424, but the link just seems to come up briefly and then drop and continues to flap between these states. Has anyone else tried this with these switches or had similar issues with others?

I've sucessufully tested the configuration between the pfsense device and another manufactures switch (MiLan MIL-SM801P). I've also been able to sucessfully create a LACP link between the Tp-Link and the MiLan switches. I just can't get it to be stable between the TP-Link and the Pfsense device. My gut feeling is that this is a bug with the TP-Link code, but it does seem to work fine with the other switch hence further investigation needed.

Everything is stripped back to bare bones:

1 interface on the LAG (em1)
No vlans on the LAG

Plug em1 into the MiLan swtich - LAG comes up striaght away

lagg0: flags=8843 <up,broadcast,running,simplex,multicast>metric 0 mtu 1500
options=4219b <rxcsum,txcsum,vlan_mtu,vlan_hwtagging,vlan_hwcsum,tso4,wol_magic,vlan_hwtso>ether 00:1b:21:c2:85:5f
inet6 fe80::21b:21ff:fec2:855f%lagg0 prefixlen 64 scopeid 0x8
nd6 options=3 <performnud,accept_rtadv>media: Ethernet autoselect
status: active
laggproto lacp
laggport: em1 flags=1c <active,collecting,distributing>Plug instead into the TP-Link and it flaps between:

lagg0: flags=8843 <up,broadcast,running,simplex,multicast>metric 0 mtu 1500
options=4219b <rxcsum,txcsum,vlan_mtu,vlan_hwtagging,vlan_hwcsum,tso4,wol_magic,vlan_hwtso>ether 00:1b:21:c2:85:5f
inet6 fe80::21b:21ff:fec2:855f%lagg0 prefixlen 64 scopeid 0x8
nd6 options=3 <performnud,accept_rtadv>media: Ethernet autoselect
status: active
laggproto lacp
laggport: em1 flags=1c <active,collecting,distributing>and

lagg0: flags=8843 <up,broadcast,running,simplex,multicast>metric 0 mtu 1500
options=4219b <rxcsum,txcsum,vlan_mtu,vlan_hwtagging,vlan_hwcsum,tso4,wol_magic,vlan_hwtso>ether 00:1b:21:c2:85:5f
inet6 fe80::21b:21ff:fec2:855f%lagg0 prefixlen 64 scopeid 0x8
nd6 options=3 <performnud,accept_rtadv>media: Ethernet autoselect
status: active
laggproto lacp
laggport: em1 flags=0<>

Testing whether a LACP link to TP-Link works at all, from the TP-Link switch I see:

When pfsense em1 connected TP-Link

SWT-TEST#show lacp 5 neighbor
Flags: S - Device is requesting Slow LACPDUs
F - Device is requesting Fast LACPDUs
A - Device is in active mode P - Device is in passive mode

Channel group 5
LACP port Admin Oper Port Port
Port Flags Priority Dev ID Key Key Number State

Output flaps between
Gi1/0/16 SA 32768 001b.21c2.855f 0 0x110 0x2 0xd
&
Gi1/0/16 SA 32768 001b.21c2.855f 0 0x110 0x2 0x3d

When MiLan switch connected TP-Link

SWT-TEST#show lacp 5 neighbor
Flags: S - Device is requesting Slow LACPDUs
F - Device is requesting Fast LACPDUs
A - Device is in active mode P - Device is in passive mode

Channel group 5
LACP port Admin Oper Port Port
Port Flags Priority Dev ID Key Key Number State
Initial state
Gi1/0/16 SA 1 0040.c830.7b50 0 0x65 0x7 0xd
Then stays stable on
Gi1/0/16 SA 1 0040.c830.7b50 0 0x65 0x7 0x3d

I don't belive the differing Priority, Operator Key and Port Numbers between these should be a factor. So the next step for me is to try and capture the LACP traffic for each scenario to see if I can work out what is different between them and why this might happen. Any advice on other things to try or gotchas I may have missed before I head down this path?

N.B. I'm currently trying this on 2.1Beta but I've had the same issue on 2.0.1 as well.</performnud,accept_rtadv></rxcsum,txcsum,vlan_mtu,vlan_hwtagging,vlan_hwcsum,tso4,wol_magic,vlan_hwtso></up,broadcast,running,simplex,multicast></active,collecting,distributing></performnud,accept_rtadv></rxcsum,txcsum,vlan_mtu,vlan_hwtagging,vlan_hwcsum,tso4,wol_magic,vlan_hwtso></up,broadcast,running,simplex,multicast></active,collecting,distributing></performnud,accept_rtadv></rxcsum,txcsum,vlan_mtu,vlan_hwtagging,vlan_hwcsum,tso4,wol_magic,vlan_hwtso></up,broadcast,running,simplex,multicast>

relmes

FYI - This seems to have been an issue with the switch. The recent firmware release (TL-SG3424_V1_130609) has a statement of "Improved the LACP function of TL-SG3424."

After upgrading the switch, it now works. Finally I can deploy the config I've been wanting! :-)

kejianshi

Thats funny… :P

I guess "working" is an improvement.