Dell switches behaving abnormal and facing network issues

I would suggest a completely separate VLAN dedicated for Management. Also, you might take a look at storm control on you switch.

 

Storm Control

 

A traffic storm occurs when incoming packets flood the LAN resulting in network performance

degradation. The Storm Control feature protects against this condition.

The switch software provides broadcast, multicast, and unicast storm recovery for individual interfaces.

Unicast Storm Control protects against traffic whose MAC addresses are not known by the system.

For broadcast, multicast, and unicast storm control, if the rate of traffic ingressing on an interface

increases beyond the configured threshold for that type, the traffic is dropped.

To configure storm control, you will enable the feature for all interfaces or for individual interfaces, and

you will set the threshold (storm control level) beyond which the broadcast, multicast, or unicast traffic

will be dropped.

Configuring a storm-control level also enables that form of storm-control. Disabling a storm-control level

(using the “no” version of the command) sets the storm-control level back to default value and disables

that form of storm-control. Using the “no” version of the “storm-control” command (not stating a

“level”) disables that form of storm-control but maintains the configured “level” (to be active next time

that form of storm-control is enabled).

 

NOTE: The actual rate of ingress traffic required to activate storm-control is based on the size of incoming packets

and the hard-coded average packet size of 512 bytes - used to calculate a packet-per-second (pps) rate - as the

forwarding-plane requires pps versus an absolute rate Kbps. For example, if the configured limit is 10%, this is

converted to ~25000 pps, and this pps limit is set in forwarding plane (hardware). You get the approximate desired

output when 512bytes packets are used.

 

CLI Example

 

The following examples show how to configure the storm control feature an Ethernet interface. The

interface number is 1/g17.Example #1: Set Broadcast Storm Control for an Interface

 

console#configure

console(config)#interface ethernet 1/g17

console(config-if-1/g17)#storm-control broadcast ?

 

                 Press enter to execute the command.

level                  Configure storm-control thresholds.

 

console(config-if-1/g17)#storm-control broadcast level ?

 

               Enter the storm-control threshold as percent of port

                          speed. Percent of port speed is converted to

                          PacketsPerSecond based on 512 byte average packet

                          size and applied to HW. Refer to documentation for

                          further details.

 

console(config-if-1/g17)#storm-control broadcast level 7

 

Example #2: Set Multicast Storm Control for an Interface

 

console(config-if-1/g17)#storm-control multicast level 8

 

Example #3: Set Unicast Storm Control for an Interface

 

console(config-if-1/g17)#storm-control unicast level 5

 

Hope this helps,

 

Keep us updated if you can.

Hi Willy,

Thank you for your solution but the problem is we have to carefully configure the storm control threshold otherwise it will once again affect the network performance right or we can only select the unknown unicast, broad and multicast option right?

We have one more query on Management VLAN is

1.  If we configure management VLAN what will be switched port mode of uplink ports i.e. trunk or General? I tried with trunk but it didn't work

2. What will be the interface mode of firewall connected interface? General or trunk. We have placed servers on VLAN 48 and it should be accessible from other locations also.

Please help us on this configuration query because we are very new to Dell switches..

Regards,

Yugandhar

Broadcast Storm Control

When Layer 2 frames are forwarded, broadcast, unknown unicast, and multicast frames are flooded to all

ports on the relevant virtual local area network (VLAN). The flooding occupies bandwidth, and loads all

nodes connected on all ports. Storm control limits the amount of broadcast, unknown unicast, and

multicast frames accepted and forwarded by the switch.

Here is a PDF with information about Storm Control.

www.dell.com/.../app_note_5.pdf

general or trunk has to specifically have the switchport allowed vlan add XX for each VLAN that will pass.  On a 62xx trunk doesn't auto include all VLANs on the 62xx