Restrictions and BAsic Config

Network Diagnose & Troubleshoot

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
  !
 !
!