Restrictions:
- XR by default supports multitopology (both IPv4 and IPv6 under same isis process) whereas IOS and XE supports single-topology (IPv4 or IPv6).
- The selection bits in NET address must be always set to 0.
- Cannot configure same NET address on multiple isis process on the same router. Even configuring same NET address on different routers running single isis process is not allowed.
- When is-type (under isis process) and circuit-type(under isis interface) both are configured, isis will prefer is-type over circuit-type.
- In case of passive interfaces, we cannot use same interface in different isis process.
- In case of Multi-instance(process) isis, starting 1byte(eg: '49.' in '49.0001' area) must be same to differentiate multiple sub-areas under same router and avoid prefixes migrating from one area to other.
Configuration:
IOS / XE:
router isis 20
net 49.0020.2000.0008.00
metric-style
wide
redistribute isis ip level-2 into level-1 route-map
FOR_L1
passive-interface Loopback0
!
address-family
ipv6
multi-topology
advertise passive-only
redistribute isis level-2 into level-1 route-map
FOR_L1
exit-address-family
!
interface Ethernet0/0
ip
router isis 20
isis circuit-type level-1
ipv6 router isis
20
isis network point-to-point
!
XRv:
router isis 20
net 49.0020.2000.0007.00
address-family ipv4
unicast
metric-style wide
advertise
passive-only
!
address-family ipv6 unicast
metric-style wide
advertise passive-only
!
interface
Loopback0
passive
address-family ipv4 unicast
!
address-family ipv6 unicast
!
!
interface GigabitEthernet0/0/0/0
circuit-type
level-1
point-to-point
address-family ipv4 unicast
!
address-family ipv6 unicast
!
!
interface GigabitEthernet0/0/0/1
circuit-type
level-2-only
point-to-point
address-family ipv4
unicast
!
address-family ipv6 unicast
!
!
interface GigabitEthernet0/0/0/3
point-to-point
address-family ipv4 unicast
!
address-family ipv6 unicast
!
!
!