Nexus 2148T versus Nexus 2248T

David Goldsmith · ‎05-25-2010

The ability to auto-negotiate between 100 Mbps and 1 Gbps that the Nexuws 2248T has -- is this a hardware difference between the two (assuming so) or a firmware upgrade. Curious to see if other than replacing hardware, there is a way to get 100 Mbps ports on Nexus 2148T fabric extender.

Ganesh Hariharan · ‎05-25-2010

The ability to auto-negotiate between 100 Mbps and 1 Gbps that the Nexuws 2248T has -- is this a hardware difference between the two (assuming so) or a firmware upgrade.  Curious to see if other than replacing hardware, there is a way to get 100 Mbps ports on Nexus 2148T fabric extender.

Hi,

Nexus 2148 It has 1Gb ports only, does not autonegotiate down to 10/100.It can be hardware specific in start of nexus series.If you configure a Nexus 2248TP port to 100Mbps speed instead of auto-negotiation ,auto-negotiation does not occur. This is expected behavior. Both sides of the link should be configured to both hardwired speed or both autonegotiate.

No speed autonegotiates, advertises all speeds (only full duplex)

Speed 1000 autonegotiates only for a 802.3x pause

Speed 100 does NOT autonegotiate, pause cannot be advertised. Peer must be set to NOTautonegotiate and fix at 100Mbps (similar to the N2248TP)

Hope to Help !!

Ganesh.H

joedelrosario · ‎06-17-2010

I tried to force speed and duplex (100 Mbps and Full-Duplex) on a 2248T port with a server connected to it, but I would not get any Layer 1 or Layer 2 connectivity. Is there a bug in the current NX-OS code (4.2(1)N1(1)) where you can't force speed or duplex on the 2248Ts? I tried different ports on different Nexus 2248T switches, but was never able to get the server to connect at 100 Mbps/Full-Duplex when it was forced. Any help would be greatly appreciated!

Thanks in advance,

Joe