VPLS level Broadcast storm

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Feb 12th, 2010
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If we have broadcast storm in the VPLS

will it be CPU processed,I mean to say like in a normal L2 switch scenario

whenever there is a brodcast storm the cpu of L2 switch will go high but in the

case of VPLS lets say in 7600 will the cpu also spike.

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Laurent Aubert Fri, 02/12/2010 - 18:00
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On 7600, broadcast will be punted to the RP CPU if the router has a L3 interface. If there is no L3 interface, broadcast may be punted to the SP CPU (IGMP snooping for ex).



tahseen12 Sat, 02/13/2010 - 03:19
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What you r saying that the CPU will spike if VPLS level broadcast

storm takes place.What if there is no laye 3 interface on 7600 just configured with vpls and L2 loop happens(cpu wud spike or no).Do u have any document refering this.


Laurent Aubert Mon, 02/15/2010 - 09:27
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The SUP of the 7600 has two CPU. Basically one for the L3 activities (RP CPU) and one for L2 activities (SP CPU).

Without L3 interface, broadcast are not punted and flooded in hardware. There are special cases where some specific broadcast packets may be punted to the SP CPU (we are only L2 here) like if it's an IGMP packets and IGMP snooping is enabled.

So a storm of such packets could overload the CPU.




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