Cisco 3750-X Layer 3 Switch review
The Cisco 3750 range has been around for many years now, and has a vast following. The 3750-X is the new kid on the Cisco block, and it combines plenty of stuff that will be familiar to users of its predecessors with some funky new features that are clearly a step forward.
The device comes in a number of flavours – between 12 and 48 ports, with or without Power over Ethernet. We had the 48P, which is the PoE variant of the 48-port device. Now, the traditional 3750 had four 1Gbit/s SFP ports in addition to the 48 10/100/1000 copper ports; the 3750-X instead has a slot into which you can slot either a four-port 1Gbit/s SFP daughter-board or a two-port 10Gbit/s alternative. In these days when 10Gbit/s Ethernet is almost a commodity, I can certainly see myself making use of the latter both for uplinking to core switches and for hooking into the 10Gbit/s ports that are becoming prevalent on blade servers.
Alongside the port combinations, there are three software installs. The LAN Base software is a layer-2 only software image, and quite frankly I wouldn't ever expect to buy one of these if I only wanted layer-2 functionality. More sensible is the IP Base image which makes the device a proper Layer-3 routing switch, albeit with a limited selection of routing protocols. At the top is the IP Services image, which makes the unit a full-blown router (just like its ancestors – two of my BGP-shouting WAN routers are actually 3750Gs, in fact). The main market will of course be for the IP Base version.
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The rear panel is interesting too, of course. As with the older 3750s the rear panel has a pair of “stack” ports. Each stack port provides a 16Gbit/s backplane connection, and by stacking your devices in a loop you end up with a resilient 32Gbit/s backplane. From a management and configuration point of view a stack is a single virtual switch – you manage it rather like a chassis product with a number of blades. So port 1 of switch 1 is Gi1/0/1, port 3 of switch 2 is Gi2/0/3, and so on.
The important rear-panel innovation with the new 3750-X model is the provision for redundant power supplies. In the old model you had a single, non-removable power supply along with an RPS (Redundant Power Supply) connection; to use the latter and give yourself some resilience you had to buy something like an RPS2300 – an external device that was a stupid shape that didn't fit into a rack very well, had buttons on the front whose only purpose seemed to be to make things break, and on a brighter note provided up to six switches with resilient power. The new model has dual slots for removable PSUs, of which one is populated by default; it's a ten-second job to slip a second one in beside it. One of the downsides of the old 3750 was the bloody awful reliability of the internal (fixed) PSU, and I've spent rather too many hours swapping out units with duff power units, so the removable units in the -X are most welcome.
Along with the redundant PSU facility is the power stacking capability. Just as you have your data stack cables, you also now have a pair of power-stack cables on each unit, so that the total power available via all the PSUs in the stack is available for negotiated use across the whole stack, for switch power and PoE.
As with the older devices, you can add and remove stack devices on the fly. Adding a switch to a stack is a simple case of settings its ID, telling the stack to expect a new member, and plumbing it in (although in theory the stack will deal with firmware mismatches in the new member, I prefer not to tempt fate so I always pre-install the right version). If a unit fails the stack will keep on humming while you pull out the duff one and stick in the replacement, and the config will be automatically migrated to the new unit.
The only downside I've found so far, in fact, is with trying to get the new -X model to co-exist in a stack with the old 3750-G (in short, I've not persuaded it to actually work yet) but I've no doubt I'll persuade it to play before long.
The 3750-X is a really sensible evolution in an already popular family of switches in the Cisco family. Being an IOS device there's really not a great deal of difference management-wise between the old and the new, so you get new functionality with almost zero additional training requirement. I've recently added seven 48-port non-PoE versions in three of my server installations, and have just received two new pairs of the PoE variant in a couple of offices, and I'm pretty happy thus far.
- New power stacking capability is an excellent evolution.
- 32Gbit/s backplane should be sufficient for most modest installations.
- 10Gbit/s Ethernet support for uplinking or connecting to blade servers.
- Far from the cheapest switches on the market
Sample pricing for popular models:
- 24-port layer-2 only: £2,120
- 24-port with IP Base: £2,650
- 48-port with IP Base: £4,680
- 48-port with IP Base and PoE: £5,370
- 2-port 10Gbit/s module: £1,290
- 4-port 1Gbit/s module: £260
- Any Cisco dealer
- Our pricing came from PC World Business