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[Andrew Broughton]

I'm curious...

What happens when you connect 2 CAT5e/6 cables in parallel between 2 switches? That is to say, for example, connect a CAT5e/6 cable to port #1 on switch A to Port #1 on switch B and then connect a second Cat5e/6 cable between port #2 on switch A & B.
What happens? Does it work? Does one cable become redundant for the other should one cable break?
I'm not talking about the usual redundant networking used in Dante but just redundant cabling. Just like if you paralleled 2 mic cables with Y cables at each end. One cable could break and you'd still have a signal connection.
Always wondered about this but I haven't tried it.


Sent from my iPhone using Tapatalk Pro

[Rory Maguire]

Without using "Smart Switches" to manage and divide the data being transferred you will end up with packet collisions and essencially the network will ground to a hault pretty quickly.

However you can use smart switched to create an Aggregate Link, where the data being transmitted is divided between the two different ports and recombined at the other end.

This of course is keeping things very simplistic and I'm sure someone can provide a far more technically detailed answer!

[Andrew Broughton]

Thanks - looking into it further, it seems like you would just set up "LAG" on the standard recommended Ciscos.
https://sbkb.cisco.com/CiscoSB/GetArticle.aspx?docid=caae365b755f46f5989177cb68216304_Link_Aggregation_on_Cisco_Series_Managed_Switches.xml&

Someone was ranting on about how the Yamaha Dante switches didn't allow the switch to be split into main and secondary on the same switch (which isn't really redundancy IMHO, since it would only protect against cable issues, not switch failures), so it seems to me if you aren't worried about switch failures but want cable redundancy between, say, FOH and Stage, you could set up LAG on a Cisco and get some limited protection against cable issues?

[Erik Jerde]

All switches should have Spanning Tree Protocol (STP) implemented.  STP prevents loops in the network topology from causing broadcast storms.  2 Cables setup between two switches (assuming a single vlan) will result in one port being disabled.

Now doing this with Dante between your primary and secondary network switches results in those networks being merged.  Same result as plugging primary and secondary into the same switch (still assuming a single vlan).  I haven't done that (since you're not supposed to) so I don't know what would happen.

From a strictly Dante point of view there is no point in connecting primary and secondary networks together.

If you're running a multi-switch network on primary and secondary side, and have enough ports then there shouldn't be any problems having a redundant connection.  If you've got managed switches that support it you can bond multiple ports together for higher aggregate bandwidth between the switches.

If you're running multiple cables without link aggregation but just relying on STP to disable the redundant connection I'm not sure how long it takes to cut over to the redundant link should the main one get damaged.

All that said, your redundant network is there to take care of all that, you shouldn't need to run redundant cabling if you have a properly implemented redundant network.

[Ron Bolte]

Someone was ranting on about how the Yamaha Dante switches didn't allow the switch to be split into main and secondary on the same switch...

While Yamaha discourages this practice, their switches definitely allow VLAN operation with one button push.  A DIP switch lets you choose from several port configurations.  I use it on one of our stage racks.

[Andrew Broughton]

So... would setting up LAG on a Cisco SG300 result in cable redundancy?

[Erik Jerde]

So... would setting up LAG on a Cisco SG300 result in cable redundancy?

Yes.

[Bob Leonard]

Andrew,
Unless the switches are broken into VLANs and each run has it's own IP address/subnet you will create a loop which will crush your network with traffic. LAG on the SG300 will work as already stated.

[Andrew Broughton]

Thanks, all.

[Erik Jerde]

Andrew,
Unless the switches are broken into VLANs and each run has it's own IP address/subnet you will create a loop which will crush your network with traffic. LAG on the SG300 will work as already stated.

As I said earlier, STP is there to stop loops.  Works great.

[Keith Broughton]

Switches are not all that expensive and if redundancy is an important factor, set up a proper redundant network.

[Andrew Broughton]

Switches are not all that expensive and if redundancy is an important factor, set up a proper redundant network.

Of course. Just asking out of curiousity.

[Tim McCulloch]

Of course. Just asking out of curiousity.

Curiosity?  I thought there might be a story behind the inquiry and management wanted you to find a "solution".

When the Dept of Redundancy Dept kicks in.... The Tom Petty tour that used the EAW ANYA rig had multiple media and mode redundancy:  optical fiber, digital copper and analog copper (and at least 2 of each, taking different paths).  I didn't ask Scovi why he wanted that much back up, but there must have been something on his mind.

[ProSoundWeb Community]