Basic C-Class Blade questions

[DanFoxley]

Hi,

I have some C-Class blade questions. If you think a document will answer thest questions, great.

1. If I have 2 (for redundancy) Ethernet Pass-Thru Modules do I 'need' a blade switch? Could I just use an external switch?

2. Ethernet Pass Thru Modules are 'required' if IP connectivity is needed out of a server blade, yes?

[Víctor Cespón]

Half-height blades (BL460c and BL465c) have 2 integrated NICs, full-height models (BL460c, BL685c and BL680c) have 4 integrated NICs.
In a C7000 enclosure half the NICs exit though bay 1, half the others though bay 2. In a C3000 enclosure all NICs exit through bay 1.
You must insert a network pass-though or switch on those bays to have network connectivity.
One important thing is that Ethernet pass-through only works at 1 Gb full-duplex speed.
You can plug mezzanine boards on the blade to add more network, fiber channel or infiniband outputs. Then you'll need to add the corresponding output modules in the back.

[DanFoxley]

This is helpful, thanks. I'm thinking specifcally of the c3000 series. In reading your reply, it sounds as if I can use EITHER the Ethernet Pass-Thru OR a blade switch for getting network connectivity out of a server? I don't understand the difference or reason to use one over the other, Ehternet pass-thru vs. blade switch. Also, thanks for adding clarity on the mezzainine cards.

[Víctor Cespón]

In a C3000 enclosure all integrated NICs go to bay 1. If you insert another pass-through in bay 2, it will be connected to the mezzanine slot 1.
The choice of ethernet switch or passthough depends on your network administrator or policies. Ethernet pass-trough gives you a separate link to each NIC. So you'll have 16 ethernet cables on the back, which you must connect to a external switch.
The other possibility is to use a switch (GbE2c / Cisco 3020) on enclosure bay 1. You will have 5 or 8 external links to connect it to the rest of your network.

[DanFoxley]

So to be clear, using a Pass-thru is instead of a Switch? THere is no case were both would be used, in a redundant configuration? Assuming all the blade server would require the same setup?

How does the switch physically interface with a blade server? What would a 1 GB interface on Cisco 3020 be used for, uplink to another switch, connect to a blade server, or an external host?

[Mi6t0]

The connection goes through the Midplane - the blade are connected from the front side of the enclosure, the signal goes through the midplane and finish in the switch, which provides the ports for the connection with the other network devices.

Regards,

[DanFoxley]

Ah, that information is helpful, I think the piece I didn't know. Thanks.

[Mi6t0]

am happy to hear that. In fact this info stays also in the vcespon's answers, he just explained everything very detailed.

Points assignment will be appreciated :)