VC FlexFabric 10Gb/24port module / sFlow configuration

[chuckk281]

Santosh was looking for help to configure sFlow on Virtual Connect:

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Dear Team,

Request your valuable information to fix the below mentioned issue in configuring sFlow on VC Flex Fabric 10Gb / 24 port.

Background information:

• To analyze the network performance and utilization we have a software module that can monitor the device (IMC-NTA module)

• On the VC flex, need to configure sFlow to capture samples of datagrams on ingress and egress interfaces and send them to IMC-NTA module (installed on a server)

• Current version on VC is 4.21

• This sFlow configuration can be done either via virtual connect manager or through CLI.

1.  

Problem Description:

Virtual Connect Manager:

• Added sflow receiver server details and enabled it

• When I tried to add bay-1 module, it was prompting to enter IP address, subnet mask and default gateway
• Am I supposed to enter actual bay IP details or else what other IP details need to be entered ?
• When I enter bay IP that is actually assigned via OA, it gave an error saying duplicate address and this is already assigned to Ethernet module

Normally on a Network switch, we configure sFlow Agent, sFlow ports and sFlow receiver. Where sFlow agent is switch itself so its own IP address is configured.

Kindly request your inputs on this issue, Thank You !

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Input from Aaron:

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I believe it’s an IP address on the VLAN/network you are sourcing your sFlow packets from.  Since the VC box is not a Layer 3 device, you have to specify an IP address on the source VLAN/network.

It’s not well explained in the VC User Guides, but you can deduce this is by the way it’s written.

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And from Mark:

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The error you are receiving is normal. You can use the same IP Address of the module (eth0) as the sflow interface. We don’t use the eth0 interface to send sFlow packets, eth0 is connected to the OA/Management network. When you enable sflow, a new interface (call it knt2) is created and that interface is what you are assigning a IP Address to either manually or via DHCP. It appears as a regular network interface to theLinux kernel, but it is a pseudo device created by Broadcom kernel driver. No incoming traffic is allowed on that interface other than the obvious (DCHP).

sflow traffic uses the network selected in the configuration to send datagrams to the receiver. If the receiver is on the same subnet, no Gateway address is necessary.

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Other input?