Adding 100base FX module to existing 4 unit stack 1

[tech888]

I currently have a stack consisting of 4 3com switches managed as a single unit.
1 3C16988A, 1 3C16985B, and 2 3C16980A. I am going to be taking one 3C16980A out to install the 100baseFX matrix module for a fibre connection. This will obviously break my stack, Is there a way that I can keep this stack as a single unit after installing the 100baseFX module. Would port trunking allow this? Does any one know where to get good documentation on port trunking?

Thanks
Tech888

 

[tech888]

oops, I guess I wouldn't be breaking this stack at all because adding the 100baseFX module onto the 3C16980A wouldn't affect the matrix connection. (In my mind I thought the matrix connection would have to be removed in order to to install the Fibre module)

My question now, is if I were to add another switch to this stack. What is the fastest way of connection it. This would be 4 port trunking correct?

 

[tech888]

ahhh crap,

back to the original post, I guess addining a 100baseFX module may affect the stack. A stack can only have 4 devices connected to it.. would adding a 100baseFX module be considered a device.?????? If so this would be 5 devices!! and would this affect the existing stack of 4 switches.????

help!!! please!!!

 

[ADB100]

Adding a 100BaseFX module will not affect the stack - it doesn't 'appear' as a device, just an additional 2 ports. I have a 3300 and a dual-port 100BaseFX module installed, they appear as ports 25 and 26. The only difference is some of the options are not available for configuration such as Speed and Auto-Duplex. This is merely a restriction of 100BaseFX (i.e. it can only ever be 100Mb and Duplex isn't negotiated.

Andy

 

[tech888]

Thank You Andy,

Finally someone has answered my question, I have look all over the internet for at least two weeks. called 3com but my warranty is up so no help there unless I pay them!!
I'm a student doing my work term and have really no experience with switches at all and this is a part of my project! All the switches are in use so I can't do any testing. I have to give a concrete proposal and during some weekend we're gonna set it up. So to understand everthing is vital.

I still have some questions...

Anything to look out for when you connect the 100baseFX modules to the fibre?? configurations within the switch?

how did you connect the fibre to the modules? SC adapters?
can you do this yourself or should you hire someone?

what do you suggest for connecting another stack of 2 switches to the stack? port trunking?

Andy, If you can spare some time to help me out, I can send you my setup diagram in visio and ask you some other questions I'm bound to have. my email is raymond@shaw.ca

Thanks again

 

[ADB100]

The 1-port and 2-port 100BaseFX modules have SC connections so you will need to make sure you use SC-terminated Multimode fibre patch cables. Also if you are connecting the switches over infrastrucure cabling make sure it is Multimode as you can't mix Multimode and Sinle mode. Fibre Cables connect Transmit-Port to Receive-Port. Also there is no Auto-Negotiation of Duplex over 100BaseFX so you MUST set it manually and make sure they are the same at each end of the link.
If you want to increase the number of ports by adding more switches I would suggest you get hold of some 1000BaseSX modules and connect using Gigabit Ethernet, 3Com trunking (aka EtherChannel in Cisco-Speak) works but is a bit of an arse to set up and if you misconfigure things you create a loop in the network and things will just stop (unless of course you have enabled STP?)
This all sounds like you are heading for a disaster though, I suggest you get someone in to design this properly. There are many design guidelines about Switched Ethernet Networks such as VLAN's, Broadcast Domain Size, Routing etc etc. My personal preference would be to have stacks at maximum with 4 switches and then interconnect stacks via a Gigabit Ethernet Layer-3 device (router).

Andy

 

[tech888]

Andy, I think I understand the SC connections now. About adding more switches, looks like I'm gonna have to do more research into 1000baseSX and interconnecting stacks with a Gigabit Ethernet Layer-3 device router.

I appreciate your help.

Raymond

 

[valleytech]

Connecting a stack has 2 options = from the front or from the backplane. If you have exceeded the number of matrix connections on the backplane, then you should use cross-over cables from the front. I am not aware you can have more than one matrix module in a stack. I like to dedicate port 1 on each of my devices in the stack to be the uplink port to the switch. From the back of the switch, through my FX module, I can run my fiber cables. It's virtually plug-n-play.