Re: LTE modem where I can control the MTU

[Saku Ytti <saku () ytti fi>]

On Fri, 1 May 2020 at 19:00, Dovid Bender <dovid () telecurve com> wrote:

> I currently have an airlink that is connected directly to a raritan console server. The public IP sits on the 
> raritan. The airlink does not seem to have any MTU options. Ideally I would change the MTU on the interface of the 
> LTE modem wich would force the raritan to send all data < 1400 bytes per packet. I never thought about the reverse so 
> we may need something that would tinker with the MSS as well.

Exactly my use-case with ISR4331 + async NIM + 4G NIM (1RU, single
integrated power supply). Call home over 4G with unspecified WAN IP
with IPSEC.

interface Tunnel1
 description OM: OOB IPsec DMVPN - local wire out-of-band
 ip address 100.100.1.18 255.255.255.0
 no ip redirects
 no ip proxy-arp
 ip nhrp map 100.100.1.1 x.y.163.1
 ip nhrp map 100.100.1.2 x.y.164.1
 ip nhrp network-id 1
 ip nhrp holdtime 300
 ip nhrp nhs 100.100.1.1
 ip nhrp nhs 100.100.1.2
 ip route-cache same-interface
 ip tcp adjust-mss 1350
 load-interval 30
 keepalive 10 3
 tunnel source Cellular0/2/0
 tunnel mode gre multipoint
 tunnel key 1
 tunnel protection ipsec profile OOB
 hold-queue 3584 in
!
!interface Cellular0/2/0
 description OM: WAN out-of-band - SINGTEL SIM X
 ip address negotiated
 no ip redirects
 no ip proxy-arp
 ip access-group FROM:INTERNET in
 load-interval 30
 dialer in-band
 dialer idle-timeout 0
 dialer watch-group 1
 no ipv6 nd ra suppress
 hold-queue 3584 in
!
controller Cellular 0/2/0
 lte modem link-recovery rssi onset-threshold -110
 lte modem link-recovery monitor-timer 20
 lte modem link-recovery wait-timer 10
 lte modem link-recovery debounce-count 6


-- 
  ++ytti