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Community Member

4948E High CPU


we have 2 4948's with DCM connected to them.

When DCM joins to some mcast group to take traffic everything works fine.

When we connect DCM ports where we are sending traffic we got 99% CPU with process "Cat4k Mgmt LoPri".

show platform health gives next output:

bg-he-l-2#show platform health

                     %CPU   %CPU    RunTimeMax   Priority  Average %CPU  Total

                     Target Actual Target Actual   Fg   Bg 5Sec Min Hour  CPU

K5CpuMan Review       30.00  89.52     30     19  100  500   48   6    2  109:01

Port configuration is :

interface GigabitEthernet1/15

description LINK dcm xxx

no switchport

ip address

ip pim sparse-mode

load-interval 60


When we connect this port back to 7609 to 6748 card everything is ok...

Hall of Fame Super Bronze

4948E High CPU

what multicast group is used for the DCM?

what's the TTL setting?

7600s have HW limiter for some of these conditions while the 4500 does not.

Community Member

4948E High CPU

But we have problem on 4948 not on 7600... On 7600 everything works ok.

Community Member

4948E High CPU

It's seems that mcast packets are software switched on 4948 with cat4500e-entservicesk9-mz.151-1.SG.bin

I can not find command like on 7600 for hardware multicast switching.

Community Member

4948E High CPU

Issue has been resolved with downgrade to

cat4500e-entservicesk9-mz.150-2.SG4.bin multicast packets are hardware switched and there is no high CPU.

Why 15.x version switch multicast packets in software ?

Community Member

4948E High CPU

And confirmet by TAC that this bug is when source is directly connected to 4948.

There is no problem with 15.0.2-SG4...

Cisco bug id is CSCtg79438

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