On 02/10/2009 17:44, Jeff Bacon wrote:
I am looking at getting some metro waves (mostly 20-40km) between sites;
I'm working with a provider who is using passive splitters on dark runs
and they're willing to split me out a wave for near the same cost as
just running a gig switched.
I went through this some while back, and on the basis that:
- coloured xenpaks are exotic, expensive and only produced by a single
manufacturer in the world (opnext, as you ask)
- coloured xenpaks will only last as long as your 6704 card, meaning that
when you retire this kit, your entire coloured optics investment is lost
- transponders were not hugely more expensive than the prices I was quoted
for cisco coloured optics
... I decided that coloured xenpaks, while marginally cheaper in the short
term, were actually a bad strategic move in the long term. Given the way
that our network has changed since we made that decision, it turns out that
it was a good decision to make, as we're completely flexible about what kit
we use at each end of the link, and have chosen to exercise that flexibility.
There is also a much better selection of coloured XFPs on the market than
coloured xenpak.
The goal is primarily serialization latency delay reduction, not
actually running 10G of traffic - I'll be lucky to run 1-2GB (though
it'll mostly be 60-100byte packets).
If you want to cut delay for switching, you may want to consider the new
top-of-rack 10G boxes, which are typically cut-through. You may find that
these boxes + SR SFP+ + wdm transponders is quite cost favourable compared
to c6500 chassis space + 6704 + coloured xenpak. Cisco N5K may be a good
option here. But other vendors have similar style boxes (Brocade Ti24X,
Extreme X650, F10 S2410, Arista Networks *.*, etc). Oh, and the SFP+ boxes
will also run 1G ethernet on SFPs (although the N2K has some limitations).
This is a nice feature win.
1) The cisco optics appear to be in short supply and damn expensive. I
may have to go third-party. I know it's a gamble. Any other issues I
Should think about besides what's been discussed here?
coloured xenpaks are a single vendor product and I have heard that they are
mostly made to order, hence the delay.
2) Is XENPAK on 6704 viable? Any gotchas I should know about with
XENPAKs vs X2?
X2 == xenpak version 2. Their power draw is slightly less than xenpak, but
lots more than xfp / sfp+. Only HP and Cisco use X2 for ethernet switches -
everyone else uses XFP and latterly SFP+, which means that there is less
pricing pressure and and more vendor lock-in if you go down the X2 route.
Personally, I have a bit of a thing against X2, but that's just me. Make
your own mind up.
3) Does 6500 switching performance blow super-hard, or just so-so hard?
(6-15us is ok.) Yes a 4900M might be faster, or a J-product, but I don't
want to change platform really, I need NAT and don't want to use
routers, I want to keep box count down (co-lo), and having a whole box
just for passing 10G doesn't IMO make sense because I'd still have to
get it into the 6500 anyway.
The 6500 is a great 1G switch platform, but doesn't excel in the 10G range,
particularly with 6704 blades.
Nick
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