I was recently asked “How to cascade a stack of Nortel switches?”. I thought that’s a pretty easy question but probably one that hasn’t been covered well by the manuals or other material. In short you just need to physically connect the switches using the supplied cascade/stack cables. On the back of each switch you’ll find a selector switch with two options, “Base” and “non-Base”. Only one switch in the stack can be set to Base and I generally set the topmost switch (physically looking at the stack) to the Base switch. That’s really all there is to it, the software will detect the presence of the cascade/stack cables and the switches will each join the stack, numbering themselves as “Unit 1 – Base”, “Unit 2”, “Unit 3”, and so on. The ports will then be referenced as 1/1, 2/1, 3/1, etc.
There are of course some caveats, aren’t there always caveats!. You can only stack specific switches with themselves. For instance you can only stack a Nortel Ethernet Routing Switch 5500 series switch (5510, 5520, 5530) with anther Nortel Ethernet Routing Switch 5500 series. You can’t stack a Nortel Ethernet Routing Switch 4500 series with a Nortel Ethernet Routing Switch 5500 series. The stack cables are very different so it shouldn’t be too hard to figure out. The switches must have the same software version of code on them in order to stack properly. The newer Ethernet Routing Switch 4500/5500 series switches will try to automatically upgrade any switch that is added to the stack and isn’t running the appropriate software version.
You can cascade/stack older Ethernet Switch 450, Ethernet Switch 460 and Ethernet Switch 470 switches. I would not advise stacking the Ethernet Switch 450 with either the ES460 or ES470 even though Nortel claims you can. There’s no issue stacking a Nortel Ethernet Switch 460 with the Ethernet Switch 470.
Cheers!
“The newer Ethernet Routing Switch 4500/5500 series switches will try to automatically upgrade any switch that is added to the stack and isn’t running the appropriate software version.”
We have tried this, but thus far does not work in the two instances we have tested. We have Unit Unit Replacement enabled and run the secure image versions of both the ERS 4500 and 5500 software.
Will have to do some more troubleshooting of this…
Hi Tom,
I’ve personally seen an Ethernet Routing Switch 5520 stack upgrade a new switch that was added to the stack. I believe the switches need to have software v4.2 or higher. Well actually now that I’m thinking about it, the stack actually downgraded the new switch that I added to the stack. I haven’t actually tested a 4500 series switch yet.
I’ll perform another test using the secure image and post the results here.
Thanks for the comment!
I will be adding new 5520 switches to existing single switches to start a stack at two locations in the next few weeks, so I will also see how the auto update feature works.
What I wonder is if the base switch was set on the switch with the higher version?
Also, on a side note, I am wondering if anyone is having problems with the 5520 switch ip address source parameter mysteriously changing on its own? I’ve had several instances where this parameter either changes during a software upgrade, or…just changes for no reason (turning on BootP/DHCP – it should be set for configured source or off at all times). All of my switch access and config changes are monitored thru Opsware, so I know that the parameter was not changed through other means. I have seen this occur on several ERS 5520 switches running either 5.0.x or 5.1.1 software.
Hi,
I am new to this Site and also to Nortel as well, If anyone can help me or guide me to proper direction, I would be really thankful to him.
Here is the scenario.
We have around 7 Nortel 5500 series switch. One default VLAN, one subnet.
Sw 1 to 5 are cascaded to each other through SCSI cable. Same with Sw 7 & 8.
Sw 1 & 7 are connected through one ethernet LAN cable.
I need to accomplish:- (Also need your Advice / direction)
Configure Trunking between sw 1-7 & 5-8 by reserving four ports on each switch.
We do not want to create VLANs at all.
I also read somewhere instead of Trunking, configuring Ethernet access port is better bet.
So guys you tell me what is best way and how to achieve that.
Thanks in advance.
Hi there,
The answer is really simple. Just connect each stack to the next stack with a single CAT5/CAT6 patch cable. Since you are running only one VLAN there’s no need to configure a trunk port or do anything else.
Just as a quick note it’s not a SCSI cable but a proprietary cascade cable from Nortel. It’s referred to as the stacking cable or cascade cable.
You might just want to make sure you enable Spanning Tree Protocol, which is enabled by default if you haven’t changed anything. STP will help prevent any loops from bringing down your network.
Good Luck!
How i can add one 470 switch to existing stack of four switches ?
I understand i need to upgrade firmware to exactly level as rest of stack and put dip switch to non-base mode, besides that doi need to make more configurations and do i need to reset all stack and request downtime for users?
Hi Semion,
As long as the switches are all running the same software and firmware (diagnostics boot code) you can just break the stack (cables) and add the new switch to the bottom of the existing stack. You’ll want to make sure that there are no alarms on the stack/cascade ports before you do this or you might take the switch down when you break the stack. After the switch boots up it will automatically be added to the switch stack as the next unit in the stack.
Thanks for the question!
Thank you very much
Hi all, I don’t know if this is exactly the perfect time to get thrown into a Nortel enviroment because of the recent uncertaintly of Nortel but here I am. Can’t compain, at least I have a job (for now). Great site and I will be refering to it regularly for tips and suggestions. My company will soon be integrating VIOP to our sites (30). Any suggestions or resources pertaining to this subject matter, thanks.
Hi!
You should find quite a bit of information here and some additional information over on the fourms. I’ve already created links in the FAQ topics to some of the more important technical configuration guides.
Good Luck!
Hello,
Anyone had a switch fail in a stack?
Let’s say 4 stacked switches, BayStack 425-48T, connected via firewire cables in tha back: 1->2, 2->3, 3->4, 4->1. 1 is the base.
Let’s say switch 3 fails. What happens then? What if the base (1) fails?
If i have another stack connected to chis one with 2 ethernet cables, configured with trunking, will the link between the stacks continue to function?
Thanks for any answer, unfortunately I can’t afford to have a test setup (to many expensive switches to buy just for testing different scenarions).
Hi SAF,
The stack is designed to be resilient to a single switch failure. You’ll obviously loose access to any devices that connected to the switch that has failed although the stack will continue to function. In the event that the base switch fails the stack will elect a temporary base switch.
It’s generally a good idea to spread your uplinks across multiple switches in the stack so if a single switch fails you don’t loose all the uplinks out of the stack.
This concept would hold true for any trunk configuration (same for any dual home servers). You would use ports on different switches in the stack so in the event of a single switch failure you would still have at least 1 link still running.
Good Luck!
Hi,
Just a quick question.
i have a stack of 5 switches and wish to select i new base unit. Base unit is currently set unit 5 would like unit 1. If i power off the base unit and move the dip switch + switch off unit 4-2 Unit 1 will be the temporary base. If i then toggle the dip switch to make it base and re-boot with the other switches connected will unit 1 stay as base and the configurations be ok?
Hi Buzz,
The selection of a specific unit (switch) to act as the base should be independent of the configuration so long as you are not re-numbering the units (switches) in the stack.
I would advise you to power down the entire stack, make your DIP switch changes and then power back on the stack.
Good Luck!
Pls. I need replace a Baystack 470 – 24 by some one from Cisco. What model is the equivalent? may I connect with the Gbic uplink?.
Thanks…
I would probably look at a 100Mps version of the 2960, you just won’t be able to stack the 2960.
Good Luck!
Hi , I have nortel 5510 switch and I am adding a 5520 24 port switch to make it a stack. I want to know if I add 5520 as a base unit will it copy all configuration from 5510 automatically?
Hi Jigar,
If you add a switch to an existing switch (assuming the base DIP switch is set) the configuration of the original switch will prevail and the new switch will be referenced as ports 2/1-24. If you want the 5520 as the base switch you’ll probably need to document your configuration, stack the switches together, factory reset them and then re-configure them.
Have a look at the discussion forums for additional information; http://forums.networkinfrastructure.info/nortel-ethernet-switching/
Good Luck!
Just wanted to drop a thank you note.
why don’t they hire you at Avaya as a technical writer is beyond me!
I am starting a new position as a network admin on a nortel network. dang, is this difficult or what. But thanks for the info! has really helped me look good in front of the boss :)
Hi Michael,
I have an urgent question, this saturday night I will upgrade my stack of 5 switches 4500 from software version 5.1 to 5.5 and also the firmware.
My question is if the following steps are right ones for you:
1. Don’t need backup the configuration because all the ports use VLAN1
2. Power off the stack
3. Disconnect all the stack cables
4. Upgrade SW and FW on each switch
5. Reconnect stack cables
6. Power on the stack
7. Connect by console to Switch Base
8. Use the wizard to assign the stack IP address, default gateway and VLAN1
9. Ready to work again.
I am missing something else?
Hi Santiago,
Heavens no… no no no!!! You don’t need to disconnect the stack cables. You telnet or console up to the base and initiate the upgrade and the base switch will automatically push the software down to all the switches in the stack. If you are in front of the switches you’ll see a cut little LED display from all the switch ports.
I would follow these steps;
1. Backup the configuration (trust me – better safe than sorry)
2. Upgrade diagnostic software
3. Wait for reboot
4. Upgrade agent software
5. Wait for reboot
6. Test that everything is working
7. Plenty of time left for drinks!
You should refer to the release notes on page 21.
Good Luck!
Hi Michael,
Thanks for the information, I appreciate it a lot. I was a little confuse at the beginning because the switch5 was disconnected from the stack and it was already with the version 5.5, so I downgraded it to 5.1 and I will reconnect to the stack again and then follow all your steps.
I have problems to backup the information, I get the following errors, Do you know what to do in this case?
4526GTX-PWR#copy running-config tftp 192.53.213.201 ?
^
% Invalid input detected at ‘^’ marker.
4526GTX-PWR#copy running-config usb runningconf.txt
^
% Invalid input detected at ‘^’ marker.
4526GTX-PWR#
You’re using the wrong syntax…
Good Luck!
Hi Michael. I currently have a stack of 3 5510-48t switches. I want to add an additional switch to the stack. I have ensured the software and diag versions matches the versions on the stack. Can I just add the switch to the stack live and will it be numbered automatically Unit 4? Or, do I need to shutdown the stack, add the switch and cables and then power up?
Thank you in advance for any insight on this.
Hi Richard,
You should be able to break the stack and insert the new switch. The existing switches can be left running, I would suggest connecting the new switch powered off. Once you have all the stacking cables re-attached you can power it up and it should join the stack showing up as the next unit in the stack.
Good Luck!
Hi Michael. Everything worked great! Thank you again for your assistance on this!
Another question if I may. What is the best process for replacing a failed Nortel 420 in a stack? I have seen different opinions on this.
Thank you sir.
Depending on the software release there is a feature called Auto Unit Replacement that can make things pretty easy. Short of that I would recommend backing up the configuration, power off stack, replace switch, factory default stack and re-number if necessary – download configuration file to stack.
You’ll find some discussions on this site and on the discussion forums.
Cheers!
Thank you for this information. I appreciate the response!
Hi Michael,
I have to replace a Baystack 420 stack (stack of 2 x 24-port switches) and add a new 48-port 4548GT-PWR to an existing stack of 3 x 4548GT-PWR switches.
Following are the tasks that need to be completed –
1) Mirror configurations of 2 x 420 Nortel Baystack 420-24T over to the new Nortel 4548T switch
2) Configure the new 4548T Nortel switch as a stack with the existing 4548T switch
3) Move cables from 2 x 420 Nortel Baystack 420-24T over to the new Nortel 4548T switch
4) Decommission 2 x 420 Nortel Baystack 420-24T
Given that I am a novice to Nortel, I have a few questions around the approach to be taken –
a. At what stage should I be replicating the switchport configs, vlan creation, vlan port assignment etc from Baystack 420’s to the new 4548GT-PWR switch? Should this be after the 4548GT-PWR has been added to the stack or should this be done before it is added to the stack?
b. How do I replicate the config from both Baystack 420 to the new 4548GT-PWR? Is it going to be a port-by-port based config copy?
c. If yes and once the config has been copied across to the 4548GT-PWR, do I just add this 4548GT-PWR switch to the existing stack & let the stack auto-unit-replacement do the magic to ensure that the switch becomes part of the stack & is number as Unit 4. Will this erase my switchport/vlan config from 4548GT-PWR switch?
d. Once the 4548GT-PWR becomes part of the stack, do I need to re-configure the switch again for switchports/vlans etc?
I will ensure that the sw/fw version on the new 4548GT-PWR is the same as the existing switches in the 4548GT-PWR stack.
Hoping for your assistance Michael.
Thank you.
Hi Rahim,
Your question is probably better suited for the discussion forum but since you’ve taken the time and effort to post let me at least do the courtesy of a reply.
You can’t stack a BayStack 420 and an ERS 4500 series switch so any configuration changes/migrations will need to be handled manually. Assuming you only have a few VLANs I would suggest you document the existing switch and then configure ports on the new stack (after adding the new switch to the existing stack of 3 switches). You can even setup an 802.1q tagged trunk port to bridge the traffic between the old stack and the new stack so you can physically move the connections one at a time.
Assuming you’ve kept all your ports at auto-negotiate you should only need to worry about VLAN assignments. I’ve personally done with 300+ ports which involves a lot of meticulous documentation, document the which data jacks go to which switch ports, then document the port settings for that switch port, then document the new switch port that will be used, then configure that port. Ultimately you follow the documentation and make the physical move.
Here are some of your answers;
A) I would add the new ERS 4500 switch to the stack first, make sure it has the same FW and SW releases as the stack (save yourself another headache).
B) You need to manually document it via Java Device Manager or the CLI, then use Enterprise Device Manager or the CLI to configure the new ports.
C) AUR is only an option if you are replacing a switch in the stack that is defective… you are adding a switch not replacing a switch.
D) The first step you should take is to add the new switch to the stack… if you configure the switch when it’s a standalone that configuration will be lost when it is added to the stack.
Good Luck!
Thank you for your prompt reply, Michael. Your reply is definitively going to help me in this project. Also, thanks for the tip of documenting each switchport migration from old to new. Quiet handy !!! Much appreciated !!!
hi we have a stack of 3 nortel 420 and we want to add the 4 siwtch to the stack it is a 425 baystack
can this work ?
we have all ready added the 425 with the cascaded cables to the stack we see the cascade leds turning on but there is no negotiation and on the CLI interface we can see only the 425 if we are physically connected to it with the nortel CLI cable
what should we do for the 425 see and work as a stack with the 420 switches ?
Ami.A
Hi Ami.A,
You’ve got some pretty old hardware there… technically the BayStack 420-24T/48T and BayStack 425 24T/48T were intended to be stacked together but I believe there was a software requirement – you had to be running a certain version of software on the switches. In general you only need to connect the switches and they will stack themselves together without any intervention. Are you running at least software release 3.0 on all the switches?
Sorry I can’t offer more help.
Good Luck!
Hi Michael,
I am a beginner of Nortel Network Switch and I have an urgent question for you. The scenario is I have a production single Nortel 5520 48T switch and I need to make a stack by adding a new 5530 24 port switch to it. I’ve done everything as you’ve suggested in the post but I can’t seem to get the new switch working in the stack. The new switch is seen as unit 2 in the stack but for some reason it has no connectivity whenever I plug a device in. The base switch works fine – no dram whatsoever. It appears to me that the VLANs configuration on the base swtich does not pass thru to the second switch. Will I need to create VLANs on the second swith to be identical to the base switch and tag all the ports? Do I need to use 2 stack cables to x cross the switches? I only used one as I don’t think it’s neccessary. Also there are only 2 VLANs on the base switch: Data and VoIP which in general are commonly found on access switches.
Thank you,
Shaun
Hi Shaun,
I would advise you to review the configuration of the switch. The default configuration or any new switch/stack or switch added to an existing switch/stack has all ports members of VLAN 1. If you are not using VLAN 1 then that would explain why you are having issues communicating. You should configure the ports on the new switch in the stack (2/1-2/48) with the proper VLAN membership for those ports.
Good Luck!
Hi Michael,
May I please ask you another question. My production switch is a 5520 and I need to stack another same model to it. The new switch has a newer firmware as well as software so my question is would the new switch automatically push the new firmware and software onto the base switch – if so will the base switch lose all its configurations? It’s good if to have it upgraded automatically but not good if the configuration is lost!
Thanks,
Shaun
Hi Michael,
Thank you very much for your reply! Highly Appreciated!
Shaun.
Do you know what the max length is for the stacking cables?
I believe the maximum length you can order is 5 meters which is 16′ 4″ in length.
Good Luck!
I want to replace one of my base switch from six 425-24t Nortel switch stack.
After replacing will the new switch become a base switch?
Are there any conditions on which the switch becomes a base switch?
Also I want to restore the configuration of old switch to new switch. Are there any dependencies to restore the configuration file of switch in a stack?
If you are replacing like for like it should be straight forward… just restore the configuration. It would be wise to document the configuration just in case you have problems with restoring the (binary) backup.
You can probably find more details on the discussion forums.
Good Luck!
Hi Mike
We have a number of 5530 Nortel switches deployed in stacks. We frequently have a member of the stack fail. Obviously if this is the member with the uplinks the entire stack is inaccessible and does not work, however when it is a member all users on that switch loose service. We can’t figure what causes these failures and we would like to come up with a preventative measure. Nortel logs are not particularly forthcoming
Can you suggest anything we can do to prevent these failures.
Thank You
Why are the logs “not forthcoming”?
What software version are you running?
I was running a clinical telemetry real-time monitoring network with a stack of Avaya ERS 5530s so they can certainly work well if configured and maintained properly.
Good Luck!