[f-nsp] Jetcore prefix-based?

David Newman dnewman at networktest.com
Fri May 28 12:16:06 EDT 2004

Right. Note that it's still a TCAM. So any flow change means a new CAM
entry. I got a chance to discuss this with FDRY's CTO Karl Triebes; he
didn't dispute that this was a suboptimal choice for a backbone device.
Their answer for service providers is the forthcoming 40G box which does
route caching...


On Fri, 28 May 2004, Sam Stickland wrote:

> Found this thread:
> http://www.webhostingtalk.com/showthread.php?threadid=266371
> With some interesting snippets:
> "No, that's wrong, and if you'd taken the time to read the archetictural
> notes they published when the JetCore modules were released, you would know
> that. The JetCore modules use the same basic technology as the IronCore.
> They still have the same 3 level IPv4 TCAM, however the JetCore CAM is twice
> as large. Some of the TCAM table entries are now twice as large, though; the
> layer 4 service load balancing flow entries, for example.
> The reason JetCore is less vulnerable to random source / destination DDoS is
> that, upon a TCAM lookup miss on the ingress module, the IronCore modules
> forward the entire frame to the management module; and the management module
> then updates the ingress module's TCAM. JetCore forwards only the first 64
> bytes of the lookup miss packet to the management blade to do the same job.
> I posted on this in great detail a couple months ago. Search my posts for
> Foundry and you should find some good information."
> Unfortunately searching the site doesn't seem to reveal the post he's
> talking about.
> Sam Stickland <sam_ml at spacething.org> wrote:
> > Is the Jetcore chipset prefix-based? I've heard some reports that it's
> > actually flow based but Foundry made modifications to the previous
> > Ironcore chipset to make it preform like a prefix-based switch?
> >
> > How will a BigIron 15000 with a J-FxGMR4 preform under a DDOS attack?
> >
> > I'm also a bit confused as to the differences between the FastIron and
> > BigIron. They both seem to be Jetcore based and have similar modules
> > numbers and specs. What are the differences?
> >
> > Sam
> >
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