InterVLAN Broadcast flooding problem
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‎09-15-2015 06:56 AM
Hello,
In our deployment we have a core switch (BD 8800) connecting to edge switches (x440-24p) through aggregation switches (x460-24x).
All the ports on edge switches are configured for at least two vlans, vlan 10 is voice and an untagged vlan for data or other applications.
Now the problem is I am seeing traffic (at least broadcast) from the untagged vlans appearing in voice vlan.
This is happening all over the network hence putting extra load on all ports and as a result the IP Phones are not able to acquire IP from DHCP server. If i remove the tagged vlan (i.e voice) from a specific port then the leakage from that port into voice vlan stops.
Any idea about solving this issue ?
In our deployment we have a core switch (BD 8800) connecting to edge switches (x440-24p) through aggregation switches (x460-24x).
All the ports on edge switches are configured for at least two vlans, vlan 10 is voice and an untagged vlan for data or other applications.
Now the problem is I am seeing traffic (at least broadcast) from the untagged vlans appearing in voice vlan.
This is happening all over the network hence putting extra load on all ports and as a result the IP Phones are not able to acquire IP from DHCP server. If i remove the tagged vlan (i.e voice) from a specific port then the leakage from that port into voice vlan stops.
Any idea about solving this issue ?
23 REPLIES 23
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‎09-17-2015 07:26 PM
@Ferhan: Are you still seeing high broadcasts on your source port?
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‎09-16-2015 05:37 AM
Martin I think you didnt notice but we already found the root cause of traffic appearing to be in different vlan. It was not actually in different vlan but because wireshark was in promiscuous mode that is why it was seeing those packets from the source vlan too (which was tagged on the port where i was monitoring it). Although I am still confused about why I was not able to see any tags in packets if wireshark was reading all the raw data.And I reduced the test scenario to a single single switch and disconnected it from the network so any chance of looping etc is out of the question.
Thanks for your suggestions but right now I am focused on reducing the broadcast at source port.
Thanks for your suggestions but right now I am focused on reducing the broadcast at source port.
Anonymous
Not applicable
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‎09-16-2015 04:13 AM
The only other thing that I can think of that would create that much broadcast traffic of the same type from a single device across two different vlans is that you have a loop somewhere. I know that doesn't seem possible in the scenario you have given but might be worth turning on spanning tree / elrp ?
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‎09-16-2015 03:37 AM
I did try bootprelay before starting this thread and that didnt help.But as I said earlier i have now resolved the dhcp issue. Right now I am only interested in reducing the broadcast being generated at the source ports because apparently that is too much for extreme switches and mitel phones to handle properly (even if the source of broadcast is a single device in entire network).
