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Gig Stacking question: Catalyst 3750 / 3550

Hello we have a 3550-24-SMI (24 10/100 with 2 GBIC based uplink ports). We want to stack it with the new WS-C3750G-24TS-E (24 10/100/1000 ports + 4 SFP gig ports). Is there a way to create a gig link between the two? Or would we be stuck with a 100mbit link between them?



Re: Gig Stacking question: Catalyst 3750 / 3550

There are two major ways to Gig link these two switches, either copper or fiber. (And within the fiber category, there are three different types of optics: SX, LX/LH, and ZX. I'll just cover the SX, the most common.) Either:

1. On the Cat3550, put a 1000BASE-T GBIC (Cisco P/N WS-G5483) into one of the GBIC slots; cross-connect to a 10/100/1000 port on the Cat3750, or to a 1000BASE-T SFP module (Cisco P/N GLC-T) installed in the Cat3750. Or,

2. On the Cat3550, put a 1000BASE-SX multimode fiber GBIC module (Cisco P/N WS-G5484) into one of the GBIC slots; cross-connect to a 1000BASE-SX SFP module (Cisco P/N GLC-SX-MM) installed in the Cat3750.

Note for Solution #1: I am not sure if the 10/100/1000 ports do auto-cross. Try a straight-through Category 5 or better UTP patch cable. If it works, fine; if not, then you need a Gig Ethernet cross-over cable. Pinout as follows: pin 1 maps to 3, 2 maps to 6, 5 maps to 7, 4 maps to 8, and vice versa. All four pairs are used.

Note for Solution #2: the multimode fiber patch cable between the two switches must be at least 2 meters in length; and have SC connectors at one end (for the GBIC) and LC connectors at the other end (for the SFP module).

Hope this helps.