Using Breakout Cables

Using Breakout Cables

You’ve been building out your network for years, brick by rack unit brick, cold aisle hot aisle, 1G, 10G, 40G, 100G. Sometimes you can plan and budget, get it right from the start, and sometimes you’re putting it together the best you can. You’ve got trunks and vlans and long runs of wire. The Flying Spaghetti Monster of cables, you’ve got that covered, You’re a pro. But you’re coming up on a problem connecting legacy gear with new deployments. And It’s time to: Break out!

Used to be pretty simple. SC or LC cables, 1G or 10G. You connect the ports to each other, turn them on, and voila. You’ve got traffic. Sure, the hard work is in the config and monitoring, but the physical layer, that’s simple. With new QSFP 40G and 10G ports, though, you might not have the cables to connect your old reliable 10G ports to your new switch or router, and the options for breaking out the links can be dizzying.

The QSFP+ 40G is pretty straightforward, for the most part. If you want to break those out into 4 x 10G links, you can get a cable almost anywhere, and configure logical ports on your router to channelize from the single 40G to four different 10G ports. Note that before you attempt this maneuver, or any other like it, you should check the manufacturer’s specs to make sure the ports can be set up this way. With Juniper’s QFX models, you won’t have to worry.

You can even break out some QSFP and QSFP+ optics into other bandwidths but beware of the cost involved. There are cables out there that’ll step down a 40G port into 4 x 1G ones, but those are pretty spendy. Again, make sure you’ve got a switch that’ll accept the config, or you’re out the cost of a pretty pricey set of wires.

With a QSFP28 optic, you can typically break out the 100G into 4 x 25G channels, but the choices in compatible 25G switches are, at the moment, a little thin. If you’ve got an Arista 7280R3 their 100G QSFP28s can connect to the 25G ports on the Brocade SLX9140 or the Juniper QFX5120 or 5200, for instance. These kinds of deployments are can give you the flexibility to connect 100G ports in your core or spine and break out the other ports to less robust switches at the access or leaf layer, saving you the time and expense of a complete overhaul. Not a lot of us can replace the network all at once.

We know, all of the options might make you break out in hives, but if you keep your cool, you can just break out the ports. There are plenty of options, and if you do a little homework and make the right choices, you can deploy your network with 4 x 10G or 4 x 25G links now and move to straight 40G and 100G when the opportunity arises. 

Breakout of the drudgery, save time and headaches. Email us or call +1 (415) 230-4353 to speak to a Terabit representative and get a detailed quote today.