Network Congestion from singular VLAN

[BashedRoot]

Upgrading from Cisco 3750 to 3650 L3 switches in a few days. One problem we've had is some specific VLANS might push say about 10-15MBps consistently, and they literally hog up the network pipes, or switches it seems until the server is turned off. They're also even limited at 100 speed.

How can this problem be prevented on the 3650?

[Jason Guto]

What type of traffic is this? Could QoS be applied on the traffic? Might want to look at ether-channels to increase throughput (bandwidth will not increase).

In addition, it might also help to look at the Access Layer, Distribution concepts and the 80/20 vs 20/80 rule.

If you already have a single vlan consuming 10%-15% of your total uplink bandwidth - might be time to have a topology change.

[BashedRoot]

Hello,

I don't think any QoS is in place. I'm not sure what the client is doing, but I think it's a high packet in/out related activity. Probably data scraping or some proxy, not sure.

I know it's about 15MBps up/down consistent.

What channels are you referring to exactly? How would I increase throughput on the 3750 also in the meantime before the 3650 upgrade?

Thanks.

[Jason Guto]

Hi BashedRoot,

I am not sure if the solution of EtherChannel would fit your topology or issue. Yet, you might want to look into it.

EtherChannel/Port Channels allow you to bond up to  8 ports on your model of switch. Take a look at the following link - not sure if it is out of date, but will give  you a good place to start.

http://www.cisco.com/c/en/us/support/docs/lan-switching/etherchannel/12023-4.html#catalyst

[Deepak Kumar]

Hi,

Share your switch configuration and If possible then share traffic type also.

Regards,

Deepak Kumar

www.deepuverma.in