Ted H. Kim's Weblog

Thursday October 06, 2005

iWARP vs. IB

People often ask me what is Sun's position on iWARP (RDMA on IP, particularly TCP/IP/Ethernet) versus InfiniBand (IB). Of course, the people asking me would really like me to give a clear "this is better" answer (mostly because they have a stake in one of the two contestants). They may point out that Sun is a member of the IB Trade Association, has made public statements about it's IB support, has actual IB products and continues to invest in it. Others ask about our participation in RNIC-PI, our membership in the iWARP interoperability consortium, our current iWARP development in Solaris and our future plans.

Then, there are some who try to convince us which is better. Neither camp is immune to hype. But of course, it is not a simple comparison (as reality often is). Though it went through a tortuous history, InfiniBand is shipping today. Also, IB does have an established and expanding presence in the clustering market. iWARP is much younger. So while you can get it in some forms, its market presence is not really here yet. iWARP's big appeal is the spectre of Ethernet volume. Certainly, Ethernet has a history of defeating other networking alternatives and delivering big volume at low cost. However, the slow progress in standardizing 10G-BaseT (i.e. the low cost port/cable for 10Gb Ethernet) has delayed the real ramping on 10Gb Ethernet.

Currently, IB latency seems to be better than iWARP. It has already a path to higher bandwidth than what 10Gb Ethernet can deliver through DDR/QDR speeds and 12x cables. But when 10Gb Ethernet comes in earnest, it probably will have bigger volume (i.e. lower cost). On the other hand, IBTA is already hatching a plan to run IB over 10G-BaseT cables. That may help with physical layer costs, but that is only one variable. Both camps are laboring mightily to try other tricks to squeeze out cost (e.g. memory free cards). When iWARP really arrives, IB may try to position itself as being slightly faster and bigger bandwidth to justify any cost differences.

Anyway back to the original question ... which one is Sun supporting? In my view, the answer is both. In the end, we are not about to tell a customer that he cannot have what he wants. (Other vendors can try that approach and send any disagreeable customers to us!) If the customer likes InfiniBand, we give it to him. If customers want iWARP, we will offer that too. Obviously, there are going to be cases where one or the other might be more appropriate. We will give advice. But we aren't going to try to change people's minds.

Is this a cop out? No. It just makes business sense. InfiniBand is here today and important enough, so we need to sell it now. iWARP is not yet here, but has great promise. So we need to get it going as soon as possible. Can we afford to pass up either one? No. In both cases, there are significant opportunities. We think this is the best way to go both for us and the customer -- the customer gets to choose.

Since I said all this (plus I am just a lowly engineer), I guess I should offer all the standard disclaimers. Hey, I at least said "In my view ...". But officially, these rantings are not necessarily anyone's views but my own. And in a lame attempt at humor: some assembly required, void where prohibited, batteries not included, sold by weight not volume, do not try this at home, I misspoke (is that actually a word?), plausible deniability, actual mileage my vary, fitness for any particular purpose is disclaimed, weight loss examples not typical, etc.

Technorati Tags: InfiniBand, iWARP

(2005-10-06 10:40:37.0) Permalink