TE Tunnel using Admin Weight

Load mpls.te.base.config.with.ospf.cfg

#IOS-XE
config replace flash:mpls.te.base.config.with.ospf.cfg

#IOS-XR
configure
load bootflash:mpls.te.base.config.with.ospf.cfg
commit replace
y

The basic IP addresses, L3VPN between XRv14 and XRv13, OSPF, RSVP, and MPLS-TE has been pre-configured.

Currently traffic between XRv14 and XRv13 is not working because LDP is not running in the core. Configure an RSVP tunnel on the PEs, CSR8 and XRv11, that takes the following path, using only TE weight to calculate the path:

• CSR8

• CSR1

• CSR3

• CSR9

• XRv12

• XRv11

Answer

The easiest way to specify this path using TE metric, in my opinion, is to first ensure that all links have a high IGP cost to start with. Right now the default ref BW of 100 meg is used. Let’s set this to 10G so every link has a cost of 10. Then we can set TE metric to 1 on links we want to use.

#CSR1-10, XRv11-12
router ospf 1
 auto-cost reference-bandwidth 10000

Now under each interface we want to be in the path, we set the TE metric low. Or, we can calculate the minimum interfaces we need to set TE metric to 1 for the best path to take our desired path.

! Set TE metric for the path from CSR8 to XRv11
#CSR8
int GigabitEthernet2.518
 mpls traffic-eng administrative-weight 1

#CSR1
int GigabitEthernet2.513
 mpls traffic-eng administrative-weight 1

#CSR3
int GigabitEthernet2.539
 mpls traffic-eng administrative-weight 1

#CSR9
int GigabitEthernet2.592
 mpls traffic-eng administrative-weight 1

! Set TE metric for the path from XRv11 to CSR8
#XRv11
mpls traffic-eng
 int Gi0/0/0/0.512
  admin-weight 1

#XRv12
mpls traffic-eng
 int GigabitEthernet0/0/0/0.592
  admin-weight 1

#CSR9
int GigabitEthernet2.539
 mpls traffic-eng administrative-weight 1

#CSR3
int GigabitEthernet2.513
 mpls traffic-eng administrative-weight 1

#CSR1
int GigabitEthernet2.518
 mpls traffic-eng administrative-weight 1

Configure the TE tunnels. The dynamic path option will automatically use the TE metric instead of the IGP metric.

#CSR8
interface Tunnel0
 description TO_XRv11_VIA_WEIGHT
 ip unnumbered Loopback0
 tunnel mode mpls traffic-eng
 tunnel destination 11.11.11.11
 tunnel mpls traffic-eng path-option 1 dynamic
 tunnel mpls traffic-eng autoroute announce

#XRv11
interface tunnel-te0
 description TO_CSR8_VIA_WEIGHT
 ipv4 unnumbered Loopback0
 autoroute announce
 !
 destination 8.8.8.8
 path-option 1 dynamic

Verification

We can force CSR8 to run CSPF for the tunnel destination using the following show command. This could be done before setting up the tunnel.

And finally we can verify the tunnels are up and using the correct path:

We can verify the metric type used for the dynamic path as follows:

We could change this to IGP using two methods:

#CSR8
mpls traffic-eng path-selection metric igp
!
! or
!
int tun0
 tunnel mpls traffic-eng path-selection metric igp

#XR11
mpls traffic-eng
 path-selection
  metric igp
!
! or
!
int tunnel-te0
 path-selection metric igp