Broadcast storm-control and WS-X6704-10GE linecard

[RamJ55775]

Hi,

I have trouble with broadcast storm control on WS-X6704-10GE linecard on switchport with dozen of vlans trunked. Settings on interface regarding storm control currently are:

   interface TenGigabitEthernet3/2

storm-control broadcast level 8
storm-control action trap

Show log:

024812: Jul  6 22:45:45.686 MET-DST: %PM_PLATFORM-5-PORTDROP: Port TenGigabitEthernet3/2 dropped packets due to storm control
024857: Jul  7 03:20:52.531 MET-DST: %PM_PLATFORM-5-PORTDROP: Port TenGigabitEthernet3/2 dropped packets due to storm control

At 03:20 there was only cca. 400 Mbit/s of traffic on that interface (inbound traffic), so I am wondering how can that amount of traffic cause triggering of broadcast storm control(level 8@10G interface = 800Mbit of traffic). AFAIK that amount of broadcast traffic would cause major problems on device (cisco 6500).

Here are some additional informations:

show asic-version slot 3
Module in slot 3 has 3 type(s) of ASICs
        ASIC Name      Count      Version
            JANUS          2      (1.0)
              SSA          2      (8.0)
           ROHINI          4      (1.4)

show version
Cisco IOS Software, s72033_rp Software (s72033_rp-ADVIPSERVICESK9-M), Version 15.1(2)SY1, RELEASE SOFTWARE (fc4)

cisco WS-C6506-E (R7000) processor (revision 1.0) with 983008K/65536K bytes of memory.

Is there any problem/bug with implementation of broadcast storm control on that type of linecard?

[shekchau]

Hey,

Storm control monitors incoming traffic over an interval of 1 sec and the input rate that you get in 'sh int <int ID>' is by default of the interval of 5 minutes and least can be 30 secs. So, at the time of the b/c traffic being suppressed the input rate of b/c would have surely been more than 800mbps for 1 sec interval.

My point is, if the load-interval on an interface is even the lowest, 30 secs, the input rate is the mean of 30 secs and does not imply the traffic rate for an interval of 1 sec which is the interval used by traffic suppression mechanism in storm-control.

To check the total discards due to storm-control, you may check the output of 'show int tengig3/2 counters storm-control.

You may check the document below for reading more about storm-control:

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst6500/ios/12-2SX/configuration/guide/book/storm.html 

Regards,

Shekhar

[RamJ55775]

Hi,

Tnx for reply. You are correct, I overlooked traffic storm control interval od 1 sec and input rate interval of 5 minutes, but I'm just wondering if that linecard has some issues with traffic storm control implementation. I have read that level of 0,34% broadcast traffic on 10G interface  can crash the box, and I have broadcast storm control trap alarms triggered @ level 8.5 (that's huge amount of broadcast traffic).

show interfaces tenGigabitEthernet 3/2 counters storm-control

Port             UcastSupp %     McastSupp %     BcastSupp %  TotalSuppDiscards
Te3/2                 100.00          100.00            8.50             108833

[shekchau · Accepted solution]

Hi,

From the same doc that I shared, here is the excerpt that should answer your question:

On these modules, these levels suppress all traffic:

--WS-X6704-10GE: 0.33 percent or less

--WS-X6724-SFP 10Mbps ports: 0.33 percent or less

--WS-X6748-SFP 100Mbps ports: 0.03 percent or less

Yes, 800 Mbps is a huge amount of b/c, I would suggest you to take netdr capture when the b/c storm occurs. Below is the procedure to take the captures:

switch#debug netdr capture rx interface tengig3/2

Switch#show netdr cap

Switch#undebug all

Copy the data and paste in the tool, click here, and parse the data to know the statistics about the dump like top-talker etc.

Regards,

Shekhar

[RamJ55775]

Hi,

I'll look into debug netdr option and try to capture some traffic.

Tnx for your help.

Regards,

Ram J.