MX - ARP Aging timer

[RaphaelL]

Hi ,

Was the ARP aging timer always 15seconds ?

This is the first time I'm seeing such a low timer on a network device.

I'm used to 4hrs and 5 mins for the CAM ( which I don't think we can see on either the MX or the MS )

[CptnCrnch]

For other Cisco security devices (ASA / FTD) default ARP timeout is 5 minutes. I'd guess MX would behave like that too.

[RaphaelL]

On my fairly large networks with MX100 and bigger , it ARPs like crazy... No real world issue but I'm really intrigued.

[cmr]

Picking a random MX84 on one of our networks I get much higher numbers:

[ww]

Mx75 and 250 also has max 15 sec.

[cmr]

Some more results from us:

Single MX64 - 60 seconds

Single MX75 - 60 seconds

Single MX75 - 16 seconds...

HA pair MX84 - 60 seconds

HA pair MX100 - 300 seconds

HA pair MX250 - 60 seconds

These are all either running 17.10.2 or 16.16.3 (one MX250 pair).  The two MX75s are in different orgs and the one that had 16 seconds has one ISP and SDWAN plus licensing, the others all have Enterprise licensing.

Somewhat interesting...

[RaphaelL]

My MX450 configured as one arm concentrator are also 300s.

On a site I have 1 MS 225 that ARPs to either 10s or 15s (???)

And the MX65W ARPs at every 15s. 

Can't beat that.

[KarstenI]

I really would love to see this well documented by Meraki …