topic RE: What are the ARP and MAC table limits on x440 and x460G2? in Network Architecture & Design

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

Germán_Persello — Tue, 22 Dec 2015 20:50:00 GMT

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.

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

Kawawa — Tue, 22 Dec 2015 21:36:00 GMT

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

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

Germán_Persello — Tue, 22 Dec 2015 21:36:00 GMT

Hi Kawawa,

Thanks for your help! Do you know if there is an entry limit per-VLAN?

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

Kawawa — Tue, 22 Dec 2015 21:36:00 GMT

Actually, I was incorrect about the ARP entries, looking at the show iparp output on an X440-48t, I am seeing an 8192 ARP entry limit. and as far as I know,there aren't any limits per VLAN
X440-48t-10G.2 # show iparp
-truncated-
Max ARP entries : 8192 Max ARP pending entries : 256
ARP address check: Enabled ARP refresh : Enabled
Timeout : 20 minutes ARP Sender-Mac Learning : Disabled
Locktime : 1000 milliseconds
Retransmit Time : 1000 milliseconds
Reachable Time : 900000 milliseconds (Auto)
Fast Convergence : Off

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

Germán_Persello — Tue, 22 Dec 2015 21:36:00 GMT

Great, thanks this is exactly what I needed. Thanks a lot!

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

Stephane_Grosj1 — Tue, 22 Dec 2015 21:36:00 GMT

Hi,

the command you need to find the L3 HW limits of a platform is the following:

sh iproute reserved-entries statistics

The ARP limit for x440 is 509.

The command sh iparp gives a software limit, that you can configure, but not a hardware limit (what really matters for you).

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

Stephane_Grosj1 — Tue, 22 Dec 2015 21:36:00 GMT

didn't notice you were requesting that info also for x460-G2. This platform has the UFT capability, which gives you some latitude as you can favor L2 or L3 depending on your needs. I presume the default configuration will be good enough in most situation: 64K MAC and ~38K ARP (assuming min LPM).

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

Germán_Persello — Tue, 22 Dec 2015 21:36:00 GMT

Oh, I see... It striked me as odd that the limits were different between the one in Specifications and the one showing in EXOS. Thanks for the info on the x460-G2 too, indeed I find the default configuration good enough.

Thanks again!

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

Germán_Persello — Tue, 22 Dec 2015 21:36:00 GMT

Just a quick one though... How do these limits work in a stack? Say, two x440, do I get a combined limit of 1018 ARP entries or is it a strictly per-device limit?

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

Stephane_Grosj1 — Tue, 22 Dec 2015 21:36:00 GMT

Considering n x440 in a stack, that would be 509 for the whole stack.

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

Germán_Persello — Tue, 22 Dec 2015 21:36:00 GMT

Ok thanks, so if I make a combined stack of x460G2 and x440 the limit would also be 509? (last one, I promise)

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

Stephane_Grosj1 — Tue, 22 Dec 2015 21:36:00 GMT

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.

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

Germán_Persello — Tue, 22 Dec 2015 21:36:00 GMT

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

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

davidj_cogliane — Tue, 22 Dec 2015 21:36:00 GMT

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?

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

Stephane_Grosj1 — Tue, 22 Dec 2015 21:36:00 GMT

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).

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

davidj_cogliane — Tue, 22 Dec 2015 21:36:00 GMT

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,