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sg 300-52 constant activity

we recently purchased a sg300-52.  i was told i would need to setup a port trunk to connect it our main catalyst.  However, i was able to connect a patch cable on the two devices and ping endpoint devices on both switches.  I also noticed that the activity lights are constantly blinking.  I'm not sure why.  Is there something i can do to slow the activity light?  it blicks constantly even in times of very low activity by the endpoint.

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Re: sg 300-52 constant activity

Hi Curtis,

Other traffic such as, broadcast traffic will be occurring within the vlan and it will be propagated on uplinks for devices within the same vlan..  You may be the uplink activity LED and maybe the PC activity LED flashing at the same time.

See the wireshark screen capture below taken from my PC.  It shows about 7percent of the traffic was broadcast or multicast related  traffic that will be broadcasted to all switch ports in the the same vlan. looking closely at this 10 second capture you will notice that 9.43 % of my traffic are plain old Layer 2 ARP packets.  I am not concerned.

Broadcast and multicast traffic within a vlan is normal.  Abnormal,  is when there may be too much of that traffic (many thousands of packets a second ) maybe due to some sort of Denial of service attack or bad NIC card. If multicast video is floating around , you may see several thousand packets per second for each multicast video stream.

Should you worry, not unless there is a denial of service attach going on.  Your symptoms however just indicate the activity LED is flashing, that sounds normal. If this LED  is almost always or flashing with great repetitively, then it's worth a wireshark trace to see what might be happening.

regards Dave.

Grab wireshark, and get a feel for the rate of traffic that is hitting the switch. I would think that rate of broadcast traffic shoudl not be too great.

2 REPLIES

Re: sg 300-52 constant activity

Hi Curtis,

Other traffic such as, broadcast traffic will be occurring within the vlan and it will be propagated on uplinks for devices within the same vlan..  You may be the uplink activity LED and maybe the PC activity LED flashing at the same time.

See the wireshark screen capture below taken from my PC.  It shows about 7percent of the traffic was broadcast or multicast related  traffic that will be broadcasted to all switch ports in the the same vlan. looking closely at this 10 second capture you will notice that 9.43 % of my traffic are plain old Layer 2 ARP packets.  I am not concerned.

Broadcast and multicast traffic within a vlan is normal.  Abnormal,  is when there may be too much of that traffic (many thousands of packets a second ) maybe due to some sort of Denial of service attack or bad NIC card. If multicast video is floating around , you may see several thousand packets per second for each multicast video stream.

Should you worry, not unless there is a denial of service attach going on.  Your symptoms however just indicate the activity LED is flashing, that sounds normal. If this LED  is almost always or flashing with great repetitively, then it's worth a wireshark trace to see what might be happening.

regards Dave.

Grab wireshark, and get a feel for the rate of traffic that is hitting the switch. I would think that rate of broadcast traffic shoudl not be too great.

Community Member

sg 300-52 constant activity

i went ahead and did this. i found that the sample captured 266 packets in 20 secs.  Definately not bad . Majority of the packets are arp and netbios.

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