Connectivity Guide

Pinning FCoE trac to a specic port of a port-
channel
You can isolate FIP and FCoE trac by conguring a pinned port at the FCoE LAG.
FCoE LAG is the port-channel used for FIP and FCoE trac in the intermediate switches between server and storage devices.
VLT provides Active/Active LAN connectivity on converged links by forwarding trac in multiple paths to multiple upstream devices
without STP blocking any of the uplinks. This works for Ethernet trac, but FCoE requires dedicated links for each SAN Fabric. FCoE
trac sent on VLT breaks SAN fabric isolation.
The FC sessions form between FC nodes and FCoE sessions happen between Ethernet nodes.
To form FC or FCoE sessions, the fabric login request and reply must traverse the switch through the same port. The fabric login request
initiated from the server through the switch reaches the SAN Fabric. The login accept response is hashed out to any of the ports in the
port-channel. If the server receives the response on a dierent port than where the request was sent, the server keeps retrying the
request. Because of this action, the FC or FCoE sessions learnt based on the login accept response change to the unstable state. The
sessions keep apping until the request and response converge in the same port. To avoid this, pin one of the ports in the port-channel.
To support FCoE on multi-level VLT networks, use port pinning in FCoE LAGs. Port pinning is a static conguration that restricts the FIP
and FCoE trac to one port of the port-channel overriding hardware LAG hashing. The system classies and redirects the packets
exchanged during FCoE sessions to the port based on the ACL conguration. The remaining Ethernet trac ows through both the pinned
port and other ports in the port-channel, based on LAG hashing. Dell EMC recommends to use pinned port if there are more than one port
in FCoE LAG. In a VLT network, the server has two unique FCoE sessions to SAN fabric and the trac ows based on pinned port
conguration. If there is only one port in the port-channel, there is no need for a pinned port.
NOTE
: The pinned port conguration is supported on FSB, Ethernet downlink port-channel of NPG, and F_Port mode.
Limitations:
• The system uses an ACL table for ENode MAC with a redirect port option similar to FCF. This limits the number of FC or FCoE
sessions.
• When the pinned port goes down, you must manually re-congure another active port in the port-channel as pinned port. You can
perform this re-conguration only in the intermediate switches, but not in the server.
• If there is a mismatch in the conguration or if the pinned port goes down, the system does not use other ports in port-channel even if
there is a valid path to server and storage device.
• When you add or remove a pinned port when FCoE sessions are active, the system clears and re-initiates the FCoE sessions based on
the conguration. The system displays warning messages during the conguration.
The following illustrations show VLT and non-VLT networks with FCoE trac owing through pinned port.
Fibre Channel
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