Dell EMC SmartFabric OS10 User Guide Release 10.5.0

Multi-hop FIP-snooping bridge

In typical deployments, ENode-connected switches are not directly connected to the core FC switch. Multiple intermediate switches are connected in between the switches. To establish a point-to-point connection and for secure transmission between the ENode and the FCF, all intermediate switches must support FSB to pass the FIP and FCoE traffic.

OS10 switches support the multi-hop FIP-snooping bridge. You can interconnect multiple FSBs to communicate with an upstream FC switch.

• Access FSB— This is the node that is directly connected to ENode. In the following example, FSB1 is the access FSB.
• Core FSB— This is the node that is directly connected to the FCF. In the following example, FSB2 is the core FSB.

The default port mode is the ENode. You must explicitly configure the other modes using the fip-snooping port-mode command. The following port modes are supported:

• ENode—Only one ENode MAC address per interface can be learnt. Configure this mode on the port connected to the ENode.
• FCF—If you configure the FSB with FCF port mode, all the FIP packets sent between the ENode and the FCF are snooped and the sessions and ENodes are learnt. Configure the FCF mode on the access FSB ports connected to the FCF-facing side.
• ENode-transit—This mode is configured on the intermediate FSBs or Layer 2 (L2) DCBX switches to which ENodes are connected.
• FCF-transit—Only the FCF advertisement and VLAN responses are snooped to learn the FCF. The FCF-transit does not learn the ENodes and session information. Configure the FCF-transit mode on the FCF-facing side of the core FSB switch.

The FCF can be in NPG or F-Port mode. The access FSB switches validate the frames and installs ACLs per the FCF to allow only FCoE and FIP traffic across the FCF.

Clear virtual link frames

When an FSB clears an FCoE session for some reason, the other devices in the network, such as the ENode, FCF, and transit switches, are not informed and considers the session to be intact. FSB drops the FCoE data corresponding to the cleared session. The ENode takes a long time to identify the issue and to recover from it. At times, interface flapping occurs and might require manual intervention to recover. To recover automatically, FSB sends a Clear Virtual Link (CVL) frame from the FCF to the ENode.