[c-nsp] Segment Routing

[Mohammad Khalil]

Hi all
I came across segment routing and tried to simulate it using the below topology
CE1 -- XR1 -- XR2 -- CE2

ISIS is the running IGP between the XR boxes and below is the relevant configuration

XR1
router isis 1
 is-type level-2-only
 net 49.0001.0000.0000.0010.00
 address-family ipv4 unicast
  metric-style wide
  segment-routing mpls
 !
 interface Loopback0
  address-family ipv4 unicast
   prefix-sid index 1001
  !
 !
 interface GigabitEthernet0/0/0/0
  address-family ipv4 unicast

XR2
router isis 1
 is-type level-2-only
 net 49.0001.0000.0000.0020.00
 address-family ipv4 unicast
  metric-style wide
  segment-routing mpls
 !
 interface Loopback0
  address-family ipv4 unicast
   prefix-sid index 1002
  !
 !
 interface GigabitEthernet0/0/0/0
  address-family ipv4 unicast

XR1
router bgp 1
 address-family vpnv4 unicast
 !
 neighbor 20.20.20.20
  remote-as 1
  update-source Loopback0
  address-family vpnv4 unicast
  !
 !
 vrf MSSK
  rd 1:1
  address-family ipv4 unicast
   redistribute connected

XR2
RP/0/0/CPU0:Clone#sh run router bgp
Sun Sep 13 11:37:16.085 UTC
router bgp 1
 address-family vpnv4 unicast
 !
 neighbor 10.10.10.10
  remote-as 1
  update-source Loopback0
  address-family vpnv4 unicast
  !
 !
 vrf MSSK
  rd 1:1
  address-family ipv4 unicast
   redistribute connected

The issue is that I cannot any labels imposed :
RP/0/0/CPU0:XRnew#sh cef 20.20.20.20/32 | inc labels
Sun Sep 13 11:37:37.416 UTC
     local label 17002      labels imposed {ImplNull}

RP/0/0/CPU0:Clone#sh cef 10.10.10.10/32 | inc labels
Sun Sep 13 11:37:54.372 UTC
     local label 17001      labels imposed {ImplNull}

Another weird issue am facing is that when I change the prefix-sid index on both XR boxes to (15001 , 15002 respectively) , no labels are shown at all 

RP/0/0/CPU0:XRnew#sh cef 20.20.20.20/32 | inc labels
Sun Sep 13 11:38:47.211 UTC

Any ideas guys?

Thanks

BR,
Mohammad