Inspect for physical damage to the connector, the module, and the module slot. Replace the SFP module with a known good SFP module if available. Try installing it in another SFP port if available to see if the problem persists or goes away. Small Form-factor Pluggable modules (SFP module) are the workhorses of modern network connectivity, enabling flexible fiber optic or copper links between switches, routers, firewalls, and servers. Whether you're upgrading bandwidth, replacing a faulty unit, or reconfiguring your topology, knowing. When replacing an optical module, do not look into the optical port without eye protection. Laser beams from the optical port can cause eye damage. The device must use optical modules recommended on the configurator because non-Huawei-certified optical modules cannot ensure transmission reliability. You can remove and replace the network module (NM-2) in the Secure Firewall 3100. HUAWEI WDM Documentation:.