Information: Double Up SFPs For A Speed Boost!

The implementation of 10G on the backbone is becoming more common, and it’s not just the big data centres and large corporates taking notice now. Smaller sites with high demand users, such as schools and hotels to name a few, are beginning to realise the potential of increased bandwidth for delivering services over the network such as communications, centralised storage, on demand video and more.

In an ideal world upgrading to 10G would be as simple as swapping out SFP modules for SFP+ modules. (And if you are lucky enough to be in that situation then Advance are here to help!) Unfortunately not all fibre installations are equal, and there are a significant portion of sites using multimode fibre that is not laser optimised, or over the maximum distance for 10G. In these instances a simple module swap is not enough, and many IT managers may be facing an invoice of significant value and weeks of inconvenience to upgrade existing fixed installations to OM3 or OM4 fibre.

There may be a solution though for those in similar situations. Most installations have some dark fibres available – cores of fibre that are currently unused. This is typical as multicore fibre cables come in 4 cores and above, and generally networks will utilise only 2 cores for a link. Secondly it is almost impossible to find network switches with only a single SFP port on them, so chances are the switches in use today will have a spare port available. So why not use these spare fibres and SFP ports?

By adding in another Gigabit SFP at each end of the link, you double the bandwidth between the switches for very little cost. Yes, it is not going to rival a 10G link for outright performance any time soon but still that extra Gigabit increase can have a significant and noticeable effect for a link that is currently struggling.

Of course there is some configuration to be done to make this work, and the correct configuration should be verified before plugging in the additional SFP modules, otherwise your switches may detect the second link as a loop and shut down the ports to protect the network. Link aggregation should be enabled on the SFP ports first, effectively telling the switches to consider the two ports as one on each end of the link.

On most managed switches such as Cisco and HP you’ll need to create a trunk group and add ports to the group. Generally lower end smart switches such as Netgear, you need to add LAGs (link aggregation groups) and add ports to the LAG membership. Both methods are effectively doing the same thing, it’s just the terminology used that differs. If you are given the option between static and LACP I’d advise the latter as it takes a lot of the manual configuration work out of things and adds some level of resilience in the case of a component failure in the link, falling back to a single link rather than shutting the whole LAG down.

Adding in a couple of SFP modules is a far lower investment than an entire fibre backbone re-install and new switches to support 10G. It provides a reasonable boost in network capacity that may help bridge the gap between ‘struggling on by’ and the inevitable upgrade in the future. Advance are here to discuss your exact requirements with you and advise on suitable solutions. Drop us a message or give us a call – all our details are here, and we will be happy to help!