[j-nsp] MX/MPC maximum routes

[Nathan Ward]

> On 22/10/2021, at 12:44 PM, Dario Amaya via juniper-nsp <juniper-nsp at puck.nether.net> wrote:
> 
> Hello,
> 
> We using the following hardware:
> 
> CHAS-BP-MX480-S
> SCBE-MX-S
> RE-S-1800X4-16G-S
> MPC-3D-16XGE-SFPP
> MX-MPC2E-3D
> 
> This router is carrying full IPv4 and IPv6 table with current routes
> count at 846528 ipv4 and 128831 ipv6
> 
> Does anybody know maximum limit for those MPC cards, I read somewhere
> it is 1M routes? What happens when this exceeds, do we need new line
> cards in the near future?

It significantly depends on your configuration and topology. For example, if they are eBGP routes with a single next hop, that’s a lot less memory than iBGP routes over multiple possible LSPs.

Full tables on those cards in an MPLS network with multiple eBGP exit points, you need to be pretty careful about your scaling. No MPLS, and that as the only full table router, and only one full table, you might be OK.

Keep an eye on `show system resource-monitor fpc` and `system resource-monitor summary` if you are on a more modern JunOS.

Be aware that changes - i.e. if you have multiple full tables on different routers, and you change local pref on one to be higher than the other - will impact your memory as preferred paths move from external to internal. You will also need overhead to deal with transitions / churn.

You can also poke around in `request pfe execute target fpcX command "show jnh 0 pool usage”` etc.

This is a good reference:
https://www.oreilly.com/library/view/juniper-mx-series/9781491932711/ch01.html

--
Nathan Ward