What are the ARP and MAC table limits on x440 and x460G2?

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Hello everyone,

I'd like to know the ARP and MAC table limits on both the x440 and x460G2, and I wanted to know if there's a per-VLAN limit for MAC addresses or if it's more of a 'global' limit.

Thanks!

Germán.
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Germán Persello

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Posted 3 years ago

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Kawawa, GTAC

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Hi Germán,

Below is a link from out website, if you look under Specifications, you'll see every limit (16K FDB entries and 509 ARP entries, if I'm not mistaken)

http://www.extremenetworks.com/product/summit-x440-series
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Grosjean, Stephane, Employee

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No.

EXOS has several patents in order to manage cleverly such scenario. In such a case, the x440's would still be limited to 509 (no miracle), but the x460-G2 could use their HW limit. EXOS would then try to figure out what would be the most used 509 entries for the x440 to optimize their usage. Of course, this would require some CPU work in order to fit the most used 509 entries in the x440, and if you really need more than 509 ARP, a lot of slow path forwarding would happen (CPU forwarding).

In the case of L3, I'd not recommend to mix such different platforms if you need more than the x440 L3 capacity.
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Germán Persello

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Ok, I see it's a more complicated scenario. Thanks for explaining how EXOS works in this case, you've been really helpful.
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David Coglianese, Embassador

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Stephane,

It was my understanding that when stacking 440-G1s with 460-G1s that stack only had access to the table sizes of the 440s.

We actually had to remove 440s from mixed stacks that were routing to because of the limitations they were causing.

Has this changed? 
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Grosjean, Stephane, Employee

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Hi,

For L3 I do not recommend to mix with x440 (especially x440 because of their very low L3 capacity). I think I clearly state it above, and your experience proves it.

What I was trying to say in the post above, is that EXOS tries its best. But at the expense of CPU usage and possibly some slow-path... that can be a life saver if you're close to the limit of the lesser one. But no miracle will happen and if too many entries, you're doom.

The x440G1 is hardly a L3 switch imho, you really need to be sure of the (small) size of the network. But EXOS behavior is very interesting with intermediate switches (in a stack) or modules (in a chassis).
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David Coglianese, Embassador

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I think I missed the last line of your previous post. 

The lesson is to read the whole message and not just the main paragraph.

Sorry about that,