Hello,
On XR1's gi0/0/0/0 mtu is 1300. And XR2's gi0/0/0/0 mtu is 1400. Even though MTU on both the routers is different still isis adjacency comes up on both the XRs.
According to my understanding, If there is an MTU mismatch then isis adjacency should not come up.
xr1
----------------------------
int gi0/0/0/0
ip address 100.10.20.1 255.255.255.0
no sh
mtu 1300
int lo0
ip address 1.1.1.1 255.255.255.255
router isis 1
net 49.0001.1111.1111.1111.00
address-family ipv4 unicast
advertise passive-only
exit
int gi0/0/0/0
address-family ipv4 unicast
int lo0
passive
address-family ipv4 unicast
xr2
---------------------------------------
int gi0/0/0/0
ip address 100.10.20.2 255.255.255.0
no sh
mtu 1400
int lo0
ip address 2.2.2.2 255.255.255.255
router isis 1
net 49.0001.2222.2222.2222.00
address-family ipv4 unicast
advertise passive-only
exit
int gi0/0/0/0
address-family ipv4 unicast
int lo0
passive
address-family ipv4 unicast
Thanks,
Sachin
