I’m in the process of choosing hardware
for a 30 story building. If anyone has experience with this I’d appreciate any tips.
There are two fiber pairs running up the building riser. I need to put a POE switch on each floor using this fiber.
The idea is to cut the fiber at each floor and insert a switch and daisy chain the switches together using one pair, and using the other pair as the failover side of the ring going back to the source so if one device fails it doesn’t take the whole string down.
The problem here is how many switches can be strung together and I would not try more than 3 to 5. This is not something I typically do (stacking switches). I have fears of STP and/or RSTP issue stacking past Ethernet switch to switch limits (if they still exist??)
Is there a device with a similar protocol as the old 3com (now HP IDF) stacking capability via fiber?
I’d like to use something inexpensive as its to power ubiquiti wifi on each floor. Ideally if you know something I don’t about ubiquiti switches that can do this I’d appreciate knowing.
Hey Norman,
I’m in the middle of a construction project where we’ve got 50 data rooms in one building.
I’ve researched a lot of different options and we ended up with just home runs.
A couple of items to consider and think about:
Have you looked into the incremental additional costs associated with more fiber? Smallest that we’ve seen trunk fiber is 6 strands of SM fiber. When you look at pre-termed fiber with MTP/MPO connectors, it might be worthwhile to have home runs to each floor.
L2 rings IMHO seem pretty brittle. I know there are L2 ring products like Juniper BTI, which use ERPS and not strictly STP/RSTP to move blocking ports, and those seem a little better although it’s mostly statically configured.
With one pair going up the stack and another coming down, what happens when a device in the middle releases some magic smoke? Do you have 2 devices at each landing?
Now that I’ve (maybe?) shot holes in some arguments, my personal preference, in a situation like this, would be to use passive DWDM.
With an OADM at each floor, you can easily terminate all the wavelengths at the home run location and have “dedicated” L1 paths to each floor. You could use the 2nd pair of fiber to even set up some form of link-agg if you so choose.
Another non-optimal option might also be something like GPON, although I’ve stayed away from that.
Passive DWDM would also give you room for expansion and you could have 10Gbe optics at each floor which would give you the full bandwidth at each landing.
Hope this helps. I’d be curious if anyone else has ever used DWDM in an intra-building scenario.
I’d say a pair of Juniper switches on each floor, with their virtual-chassis capability. Terminate the top/bottom floor of fiber 1 into switch 1, and the other into switch two. Create an LACP bond between each floors switches, tag the necessary VLANs, and put the VLAN SVIs onto the first pair of switches at the building electrical/telecom room.
The same thing can be done with MLAG across many switch vendors, but that will require additional configuration.
I’m in the process of choosing hardware
for a 30 story building. If anyone has experience with this I’d appreciate any tips.
There are two fiber pairs running up the building riser. I need to put a POE switch on each floor using this fiber.
In my experience with retrofitting existing structures, if you have access to the riser at each floor as it sounds like you do, you would typically drop in a new duct, blow micro duct through it with a branch for each floor, have an MDF or two In a utility spaces and them you have the ability to reconfigure the fiber as necessary to meet your present and future needs.
You didn’t specify if the existing fiber is single or multi-mode however it is unlikely that the was enough slack built into two fiber runs to make 30 additional splices so that approach seems dubious as a premise.
As you correctly surmise daisy chaining 30 switches is not an advisable network design practice.
Also, Juniper switches will stack over fiber. I have deployed Virtual
Chassis over multiple IDFs. The VC ports can be (and highly suggested)
to be in a ring.
Yeah… I’d regenerate every five L2 devices as well. Which just means going up to L3 periodically. Would it work for you to use the first pair for daisy-chaining switches on each floor that’s not a multiple of five, and then put the switches on the floors that are multiples of five into router mode, with a switch-group facing their own floor, but routed ports facing other floors? Then use the second pair as an “express” lane between the exit, floor 10, and floor 20, to keep L3 hop-sounds down and provide some redundancy?
I would use single fiber CWDM muxing and OADM, then you can get it down to 7-8 switches per fiber. CWDM single fiber has a max of 9 channels and the optics are typically less expensive.
Sent: Wednesday, February 26, 2020 4:46 AM
To: Norman Jester <nj@jester.mx>
Sent from my iPhone
>
> I’m in the process of choosing hardware for a 30 story building. If
> anyone has experience with this I’d appreciate any tips.
>
> There are two fiber pairs running up the building riser. I need to put a POE
switch on each floor using this fiber.
In my experience with retrofitting existing structures, if you have access to
the riser at each floor as it sounds like you do, you would typically drop in a
new duct, blow micro duct through it with a branch for each floor, have an
MDF or two In a utility spaces and them you have the ability to reconfigure
the fiber as necessary to meet your present and future needs.
You didn’t specify if the existing fiber is single or multi-mode however it is
unlikely that the was enough slack built into two fiber runs to make 30
additional splices so that approach seems dubious as a premise.
As you correctly surmise daisy chaining 30 switches is not an advisable
network design practice.
+1 to that,
Put your own fiber in and do a star topology to an MDF device.
Single mode fiber for all new installs. There are only few uses cases where multimode still saves a little money (100G optics) but otherwise there are only downsides in my opinion. Single mode on the other hand will always work no matter what application.