We are attempting to test a WAN link and the the internal LAN equipment that is in the path between two sites which will be used for replication. The test units are IXIA Model 250 packet generators with 1 Gbps LC fiber Ethernet ports. We are attempting to connect to a 2148T port with the IXIA but are having issues with maintaining the link between the two devices. We have used these units for years with most models of Cisco switches and know most of the issues that cause link problems. I've read through the documentation for the 2148T and the Nexus 5000 but don't see any way to set the parameters such as link negotiation or duplex as with Catalyst switches. I did read the posting that mentions there is no speed configuration on 2148T ports; but, can other parameters such as link negotiation be changed? I may be overlooking the answer; but, I don't see in any of the documentation where this is addressed.