SG550X Capabilities

[ammartalal]

Hello Everyone,

We have a number of Cisco SG550X-24-K9 switches, they are used as ToR switches for the Data Center (physical servers).

I enabled jumbo frame on all switches, but I am unable to set the MTU of the interfaces, neither from the UI nor from the CLI. I am also unable to check the current MTU for a certain interface. We are facing slowness in the network throughput on a few of the switches (they replaced Catalyst 2960G). As per the Data Sheet of the SG550X switches, switching capacity should reach 128 Gbps, but with only 2 servers connected we can get a throughput of 20 MBps, which is much lower than what we used to get on the older Catalyst 2960G switches.

Is there anything that needs to be modified or done to make the throughput faster on these switches?

[balaji.bandi · Accepted solution]

Personally these are not suggested to use DC environment, mostly these are small business access switches.

I was not suggested you should not use it, some people use it with their convinient.

They should get decent throughput  - we need to know how you testing ?

MTU concern :

If jumbo frames are disabled, the L3 traffic MTU for traffic is limited to 1518 bytes.
If jumbo frames are enabled, the L3 traffic MTU for traffic is limited to 9000 bytes.

Look at the ADmin guide how to setup :

https://www.cisco.com/c/en/us/support/switches/550x-series-stackable-managed-switches/products-maintenance-guides-list.html

but with only 2 servers connected we can get a throughput of 20 MBps

what servers are these, what speed they negotiated ? do teh server support jumbo frames ? what is the outcome default MTU ?

[Martin Aleksandrov · Accepted solution]

@ammartalal 

In addition to balaji, jumbo frames can be enabled/disabled globally for the system but not per port/interface. You might be seen that the changes will take effect only when enable the jumbo frames, copy run to start config and restart the switch. 

You have to further investigate servers' NIC configuration/jumbo frame support/teaming etc and make sure these match the switch port values. Furthermore, you look at switch port settings like auto advertisement/negotiation (should not be auto), flow control and MDI/MDIX. Using any SFPs?

Thanks,

Martin