In a previous post entitled, “Ethernet Switch 470 Stack Troubleshooting“, I discussed how to troubleshoot stacking issues between Ethernet Switch 470 switches and I highlighted some caveats that can prevent switches from stacking properly. As I mentioned in that post I wanted to cover the Ethernet Routing Switch 5500 series and provide some basic troubleshooting steps for those.

Let me start by telling you (if you don’t know already) that you can’t stack Ethernet Switch 460/470s with the Ethernet Routing Switch 5500. You also can’t use the Ethernet Switch 460/470 cascade cables with the Ethernet Routing Switch 5500 series switches.

The Ethernet Routing Switch 5500 series has the same basic LEDs as the Ethernet Switch 470, Up, Down, Base, etc. A green light indicates that everything is good while an amber or no light indicates a problem. I’ve found the Ethernet Routing Switch 5500 series to be much easier switch to stack for a number of reasons. One long overdue feature that is now available in the ERS 5500 series is automatic firmware/software upgrade. You can add a switch to the stack and the base unit will automatically push the running firmware/software to the recently added switch. You may need to be running at least v4.2 software for this to work although I’ve been unable to confirm as of yet.

Another feature is the ability to run loopback testing of the cascade/stack ports while the switch is running the agent software, there’s no need to reboot the switch and start the diagnostic code. You can also physically test the cable by looping it between the up and down stack ports (on the same switch) and the LEDs for both ports (Up and Down) should turn amber. If they both don’t turn amber you’ve got a problem somewhere, either with the cable or with the cascade module in the switch itself.

I should note that there was also a recall by Nortel on various cascade cables manufactured in 2005. If you have any cascade cables that have an “/05” designation on them you might want to contact Nortel to see if those cables were recalled. As a side note to that I recently discovered 7 cables out of 10 that were defective out of the box. They had the manufactured date of “11212007” on the bag.

5520-48T-PWR#stack loopback-test internal
Testing uplink port ... Ok
Testing downlink port ... Ok
Internal loopback test PASSED

5520-48T-PWR#stack loopback-test external
External loopback test PASSED.

Cheers!