Can I have 2 bridges in a network

Hi,

Can I have one 60 GHZ and one 5GHZ bridge link in a network running at the same time ?

image

Switch1 connected to the internet, switch2 to multiple devices.

The reason for 2 bridges is for capacity (60Ghz) and redundancy (5Ghz).

60Ghz is much more finicky, and thus if that goes down, I still have a 5Ghz link.

Thanks

Yes, there are several ways to go about doing this.

The normal way is if you have a managed switch on both sides of the link would be to use one of the following options:

  • Link Aggregation Control Protocol
  • STP
  • Scripting

Each option has it’s plusses and minuses.
Link Aggregation Control Protocol is probably the fastest and easiest, you will need your switch to support Active Failover which will swap which link it’s sending data over when it detects the link go down. The issue with this is that many 60 GHz products don’t have a great option for indicating that their wireless link has degraded and some switches only look for the interface to go down. There are ways around this, if your switches support the full 802.3ad protocol then there is monitoring of the remote device and it will be more sensitive to various link failures.

STP is a bit more complicated, but if you set it up right, it will provide the same link failover that LACP doe and will also come pre-packaged with a solution for an ethernet port being up, but traffic not being able to flow over it. That said there will be some situations where the 60 GHz will be down in the 50 Mbps and the switches won’t swap over to the secondary link.

Scripting is the last option because it is the most complicated. If your really want to have fine tuned control over which link is getting which traffic, you would setup STP and adjust it’s settings through a script running either on each switch or a computer that monitors the 5GHz and 60 GHz management interfaces and decides if a fail over event needs to occur. This is complicated, but I know the guys at IPArchitects built a system that was doing some of this.

Hi William5,

Thanks for your comprehensive reply. :grinning:. Appreciate it.

I was hoping it was much simpler … if I just had unmanaged switch at both ends and the devices has fixed IP address and gateway defined, then wouldn’t they take any route that was available?

I don’t want to manage this link, if I could avoid it.

Doesn’t the B5c do this… when it connects with 2 frequencies… or it does the magic that you were talking about ( in the background).

Thanks

Hi Anupam 1,

If you were to do this, with just two switches (one at each end) you would create a network loop. You would need some type of layer 3 device to do routing for you at both ends, causing this to be a managed portion of the network.

You will need to do one of the options that William mentions above because otherwise this will not work.

Ya, redundant connections between two switches gets complicated somewhat quickly. If you are willing to use routers, cost goes up, but there are some more options and a bit more control. Might be easier to make something that works, but then again, you are stuck using routers and that creates other management difficulties.

The issue is that Switches don’t have any concept of TTL (Time To Live) like we do higher up in the OSI model. So you need to build around that.

Yes the B5/B5c can do this, but they basically have a network switch built into them (Not really, but in principle that’s kinda how it works out if you really want to pick at it.)

TBH there are a hundred different ways to do this, but they boil down to requiring some level of network expertise to get them setup right. You might try reaching out to IPArchitects and see if they have something that they have used in the past that is stable. I would offer my services, but everything I have built requires some level of user interaction or has shortfalls that wouldn’t work for you. (Sorry, I just have not been paid by anyone to do this exact thing so I just don’t have something up my sleeve.)

The other option would be to utilize different hardware. The B24 isn’t nearly as effected by weather as equipment that uses 60 GHz is, though price is kinda high… Another option would be to use a 60 GHz solution that had a 5GHz radio backup built into it. Both Ignitenet and Ubiquiti have products for that. TBH Ubiquiti’s AirMax 60GHz probably would be your simplest solution.

Dustin,
STP (spanning tree protocol) will handle this. STP detects the loop and blocks one of the ports. If the working link goes down, STP opens the blocked link.

Anupam1,
Using link aggregation may cause you problems. Using a switch that sends BPDUs and uses STP to detect the loop works, but it will only use 1 link at a time, with automatic fail over if the active link goes down.

The problem I’ve seen with link aggregation, such as LACP, is that the devices are on 1/2 a link. They transfer traffic fine, but trying to connect directly to the device became impossible. I had to shut down one of the link ports to send everything across a single link in order to communicate with the Mimosa devices themselves. One way around this would be to create layer 3 links across them and let routing load balance between the two links. Normally, on such a link you use a /30 network (network address, broadcast address, and 2 addresses for the end devices (multi layer switches or routers). With the Mimosas in the link, you’d need a /29 network so that you would have enough addresses for both end devices and the Mimosas on the link. I haven’t tried this using layer 3, but I suspect it would work.

Ok Guys, the answer is no – I wont use it. Unless I buy equipment – that will do it fo rme. :grinning:

Anupam,

Most fully managed switches will run STP as a default. So, as long as it hasn’t been turned off, then you could run the 2 links and the switches would shut one down automatically to prevent a loop and bring it up if the primary link failed. Again, as long as it’s a fully managed switch, this is automatic behavior. There’s nothing for you to do.

When I say “fully managed switch,” I’m talking about enterprise or small business level Cisco, Meraki, Ubiquiti, etc., where you can go in and do more than just set VLANs. For any other switches, you’d have to read the specifications to see if they participate in STP. Common indicators in the specifications that they do support STP are “802.1D”, “802.1w”, “STP”, “PVST”, “RSTP (rapid spanning tree protocol)”, “MST”, etc.

Thanks Wayne2,

Thanks for an extremely useful reply.

Can I use Ubiquiti edgeswitch for this purpose?
Or Ubiquiti flex mini?

Re: Meraki: could I just use them without a license ( may be able to get some cast off)

Thanks

Anupam

Anupam,

I suspect they do, but I’d recommend asking Ubiquiti or, if you have access to one of these switches, take a look at the settings in it and see if it has the options mentioned in this artical. Here is what Ubiquiti says about STP. If you go this way, I strongly recommend Rapid Spanning Tree (802.1w) over the original Spanning Tree (802.1d), or as my Cisco instructor used to say, “friends don’t let friends use 802.1d.”