As we are in the process of revising our co-location servers for 2010, one of the challenges that has come up is how to provide a 'communications' component that delivers:

  • Small form factor (must fit in a 1u chassis)
  • Minimum of 9 100Tx ethernet ports
  • VLAN tagging (802.1q) available on at least 4 ports
  • Remote access through IPSEC
  • Either dual PSU or two physical units
  • Low cost!

The last two normally end up as being the real sticking points - until we came across the 'RouterBoard 450G'. A small 5 port gigabit port unit. At £45 ($99) per board, this could be the answer; up until now the solution comprised two switches and a VPN endpoint; these units could do both jobs.

By using two of these small form factor boards, the dual-psu element could also be addressed. However, some searching online earlier brought up another option - to create a HA-PSU for the units from the DC outputs of the two transformers.

DC doesn't have the problem of phase issues, but when connecting up two DC supplies together, you have to take care that one doesn't try to 'back feed' the other one. We came across this circuit diagram on a number of product information sheets and with a bit of tweaking, we built it up. The result is a dual input load balancer that can supply both 450G's, even if one PSU fails.

Next step is to configure the 450Gs and get them in to the 1u chassis along with the patch cables, before hooking them up to the cluster nodes.