Deployment Guide

Exceptions

This section describes the constraints of OpenFlow.

• Dell Networking switches can operate as Hybrid switches (switches running OpenFlow and legacy functions

simultaneously). You cannot enable Legacy functionality (switching and routing) on OF ports or OF virtual local

area networks (VLANs), as these interfaces are controlled by an OpenFlow controller and are not available.

• Stacking of OpenFlow switches is not supported for the S4810, S4820T, or MXL switches. If you configure

stacking but disabled it in preparation for future stacking, the stack unit number must be zero to enable

OpenFlow on S4810, S4820T, or MXL switches.

• For OF ports and OF VLANs, the VLAN IDs used for OpenFlow must be unique; the VLAN IDs cannot be used for

legacy functionality on the same switch.

• Dell Networking does not recommend using global spanning tree protocol (STP) instances on ports with both

legacy VLANs and OF VLANs.

• Transport layer security (TLS) connections are not supported.

• Because controllers typically run their own version of link layer discovery protocol (LLDP), disable legacy LLDP

on OF ports.

• To avoid session timeout issues if you change the system clock, you must disable and re-enable all existing OF

instances.

• Controller high availability (HA) is not supported.

• Emergency flows are not supported.

• Packet buffering is not supported.

• Data center bridging (DCB) and Internet small computer system interface (iSCSI) are not supported on OpenFlow

interfaces.

• The following packet types can only be copied to the controller and cannot be forwarded from a physical switch

port:

– STP BDPU

– LLDP

– GVRP

– ARP Replies

– 802.1x frames

– untagged broadcast packets received on an OF port

ACL Flow Exceptions

• Flooding (action “output=all” or “output=flood”) is supported on S4810, S4820T, and MXL switches.

• By default, ACL flows override flows installed in the L2 or L3 tables.

• Address resolution protocol (ARP) opcode, sender IP, and target IP matching are not supported.

L3 Flow Exceptions

• Non-zero integers for the idle timeout are not supported and are ignored for L3 flows. L3 flows are not aged out.