Switching

I am getting the following log message nearly every minute:

"l2ald[1164]: L2ALD_ST_CTL_IN_EFFECT: ge-0/0/4.0: storm control in effect on the port"

However, I do not see unusually high broadcast/multicast traffic on that interface that could have triggered storm control, "monitor interface ge-0/0/4" shows only a few hundred incoming or outgoing broadcast/multicast packets per second, and the network works without any noticeable problems.

Switch: ex4300-48t (2 units in a virtual chassis configuration)

Software: JUNOS 13.2X51-D20.3

Configuration:

root@sw7> show configuration interfaces ge-0/0/4
unit 0 {
    family ethernet-switching {
        interface-mode access;
        vlan {
            members default;
        }
        storm-control default;
    }
}

root@sw7> show configuration forwarding-options
forwarding-options {
    storm-control-profiles default {
        all;
    }
} 

Port ge-0/0/4 is connected to another switch, should I use trunk mode? I don't use any VLANs except the factory-configured default VLAN (all ports in VLAN default, configured like ge-0/0/4).

Hi,

I would recommend configuring a storm control level using bandwidth (see below).  You could then monitor the log messages.  This document should assist.

http://www.juniper.net/techpubs/en_US/junos13.2/topics/example/rate-limiting-storm-control-configuring-els.html

Hi,

I have tried different settings (bandwidth-level 500000, bandwidth-percentage 80) for the default profile and also applied a specific profile to ge-0/0/4 with both of these settings but the storm control log messages still appear regularly.

I do not see any broadcast/multicast traffic peaks on that interface, values are always more ore less like this:

monitor interface ge-0/0/4
sw7                               Seconds: 68                  Time: 09:53:52
                                                           Delay: 1/0/2
Interface: ge-0/0/4, Enabled, Link is Up
Encapsulation: Ethernet, Speed: 1000mbps
Traffic statistics:                                              Current delta
  Input bytes:             4410862777054 (122528496 bps)          [1047174072]
  Output bytes:            1205514496980 (60181496 bps)            [530982310]
  Input packets:              4378117265 (15559 pps)                 [1088524]
  Output packets:             3065368861 (13648 pps)                  [941777]
Error statistics:
  Input errors:                        0                                   [0]
  Input drops:                         0                                   [0]
  Input framing errors:                0                                   [0]
  Policed discards:                    0                                   [0]
  L3 incompletes:                      0                                   [0]
  L2 channel errors:                   0                                   [0]
  L2 mismatch timeouts:                0                                   [0]
  Carrier transitions:                 3                                   [0]
  Output errors:                       0                                   [0]
  Output drops:                        0                                   [0]
  Aged packets:                        0                                   [0]
Active alarms : None
Active defects: None
Input MAC/Filter statistics:
  Unicast packets             4377525955                             [1088440]
  Broadcast packets               173374                                  [23]
  Multicast packets               417936                                  [61]
  Oversized frames                     0                                   [0]
  Packet reject count                  0                                   [0]
  DA rejects                           0                                   [0]
  SA rejects                           0                                   [0]
Output MAC/Filter Statistics:
  Unicast packets             3053495176                              [938448]
  Broadcast packets             11820938                                [3325]
  Multicast packets                52747                                   [4]
  Packet pad count                     0                                   [0]
  Packet error count                   0                                   [0]

The broadcast counters increase at less than 100 packets per second, I have watched the monitoring output for 5 minutes and got a few of these storm control log messages during that time but could not see any broadcast/multicast traffic peaks.

Hi Tobias,

L2ALD is the Layer 2 Address Learning Daemon - it's possible that storm control isn't kicking in because of brodcast packets, but the rate of new MAC Addresses being learnt.

Is it possible you have a loop in the network or some other interface flapping? (Though this may not be the case, as I would expect brodacast traffic rate to be a lot higher).

See if:

show ethernet-switching statistics | find ge-0/0/4

 gives you a clue.

Hope this helps,

Hi Tobias,

I'm facing the same issue. Can you please share the solution.

Thanks

skoppula,

This is a bit of an old thread, but...here's a few other things to try.

You can see if mac-move is an issue by enabling mac-move-limit on your switch. set a limit of 1 or 2.

If you have a mac-address cycling between different ports, it should show up here, similar to error messages generated on the old Catalyst switches. Check the log for outputs.

http://www.juniper.net/documentation/en_US/junos13.3/topics/reference/configuration-statement/mac-move-limit-port-security.html

If you get a hit on a specific mac that's moving around, you can track it down with the following command, as  you'll probably see the mac address cycling between various ports in this output.

'show ethernet-switching table'

As a matter of troubleshooting - since the EX4300 includes multicast by default in it's storm-control, you could opt-out specifically multicast traffic and see if the message continues to occur. If the messages stop, then you can be reasonably certain it's multicast traffic hitting your storm control filters. Perform the same test for unknown unicast/broadcast. 

http://www.juniper.net/documentation/en_US/junos14.2/topics/task/configuration/rate-limiting-storm-control-disabling-cli-els.html#jd0e196

Seeing this message with default settings, pretty much always means you've likely got a loop somewhere, as the default limits are pretty high for this type of traffic (multicast excluded - depending on your network).

We had this issue with that version of code.  After a tac case it turned out that there was a bug causing the mac learning not to be working correctly and thus causing flooding and triggering the storm control.

for we got recommended to go to 14.1

we have also requested some feature requests to add some detail to these storm control messages:

what is triggering it, which of the traffic types BUM, offending macs etc etc.

to make it useful.

and some way of tracing.