Meraki

Meerkat99

Hi folks,

Can anyone please advise if there is a finite number for the amount of routes that can populate the MX-100 routing table before routes are no longer reachable?

For example, in our hub and spoke configuration, we have run into instances where a client on a subnet advertised from a spoke (ie 172.25.80.0/27) is not reachable from the MX Hub who’s routes are in excess of 11500, however clients on the same subnet are reachable from a 2nd Hub who’s routing table has approx 3k routes.
Hope that makes sense!

Thanks..

alemabrahao

I once read (but couldn't find the document) that the MX100 is known to reliably support around 5,000 to 10,000 routes, but performance degradation or route drops may occur beyond that, especially in hub-and-spoke topologies with many spokes advertising multiple subnets.

But the truth is that there is no official document that attests to this.

I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.

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DarrenOC

Agree with @alemabrahao. I’ve never seen anything documented for the number of routes supported on an MX.

Did stumble across this interesting document from CiscoLive around MX performance which was a good read:

https://www.ciscolive.com/c/dam/r/ciscolive/global-event/docs/2024/pdf/BRKTRS-2007.pdf

Darren OConnor | doconnor@resalire.co.uk
https://www.linkedin.com/in/darrenoconnor/

I'm not an employee of Cisco/Meraki. My posts are based on Meraki best practice and what has worked for me in the field.

Meerkat99

Tks will have a read

Meerkat99

Thank you, it was Meraki support that suggested a hard limit of 10k but I haven’t seen any documentation to confirm this.

alemabrahao

In real life, what you need to consider is your device's memory and CPU capacity. I remember reading that you need about 1 GB of RAM for every 750,000 routes. So, even if you have, say, 128 MB (that's an example) by default, it's best to limit the maximum to 3,000 routes.

I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.

Please, if this post was useful, leave your kudos and mark it as solved.

cmr

Can you not summarise some of the routes, unless you are an ISP that seems like an awful lot of routes in one devices routing table. I would imagine the lookup time is not quick at all?

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Meerkat99

On further investigation, it seems like the hub with the large routing table is receiving the same route from the other hubs in the network (ie the same subnet appears 5 times, each from a different hub), whereas a hub with the ‘expected’ route table is only receiving the route from its spoke site.

Can anyone please advise why this is?

cmr

Are they external routes?

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Meerkat99

Hi, no they are routes from within the same organisation. Tks

PhilipDAth

Any VPN firewall rules?

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MX-100 Route Table

MX-100 Route Table