[j-nsp] Jumbo frames / mismatch MTU

[Chuck Anderson]

On Fri, Apr 23, 2021 at 01:23:32PM +0000, Matthew Crocker wrote:
> The SRX devices are limited to an MTU of 1600 due to the TLS carrier they are using to connect back to the  QFX.
> 
> I need to support 9K frames from one ACX to another over this network.  The QFX is configured for MTU of 9192 on all interfaces.  When I configure a couple ACXs with 9192 MTU the OSPF & LDP sessions go away.
> 
> I can ping ACX to ACX with 9k packets just fine.


> Everything is working.  If I ‘set mtu 9192’ everything breaks

Just set the IP MTU in addition to the physical L2 "mtu".  That way
you don't have to care about calculating any possible differences
caused by encapsulation overhead:

set interface ... family inet mtu 9000

But how are you planning on overcoming the 1600 limitation on the TLS carrier?