MPLS TE in Seamless MPLS (Inter AS)

[fraedi-hangga]

hi all,

I have lab for interAS MPLS TE using BGP label. The topology is above, the goal is to create MPLS-TE from R1 to R6

I create to build MPLS TE from Head end (R1) to tail end (R6),but stay down.

The log error was no route to destination at IP p2p R2><ASBR3 :

note: 6.6.6.6 is ip loopback R6

Name: tunnel-te90 Destination: 6.6.6.6 Ifhandle:0x14
Signalled-Name: ME5-07_t90
Status:
Admin: up Oper: down Path: not valid Signalling: Down

path option 1, (verbatim) type explicit INTER-AS-LSP
Last PCALC Error: Fri Sep 5 06:46:26 2025
Info: Path-option is skipped because it is held down
Last Signalled Error : Fri Sep 5 06:46:26 2025
Info: [4] PathErr(24,5)-(Error: routing (24), Suberror: no route to dest (5)) at 57.57.57.5 --> IP P2P R2 TO ASBR-R3
G-PID: 0x0800 (derived from egress interface properties)
Bandwidth Requested: 0 kbps CT0
Creation Time: Wed Sep 3 09:37:07 2025 (1d21h ago)
...
I have to make sure that from R1 to R6 has label by ping MPLS ipv4 (IP loopback R6) successfully 100%.

RP/0/RP0/CPU0:R1#ping mpls ipv4 6.6.6.6/32 source 1.1.1.1
Fri Sep 5 06:49:14.473 UTC

Sending 5, 100-byte MPLS Echos to 6.6.6.6/32,
timeout is 2 seconds, send interval is 0 msec:

Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0

Type escape sequence to abort.

!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 13/17/26 ms
RP/0/RP0/CPU0:R1#

RP/0/RP0/CPU0:R1#traceroute mpls ipv4 6.6.6.6/32 source 1.1.1.1
Fri Sep 5 06:50:47.703 UTC

Tracing MPLS Label Switched Path to 8.8.8.8/32, timeout is 2 seconds

Codes: '!' - success, 'Q' - request not sent, '.' - timeout,
'L' - labeled output interface, 'B' - unlabeled output interface,
'D' - DS Map mismatch, 'F' - no FEC mapping, 'f' - FEC mismatch,
'M' - malformed request, 'm' - unsupported tlvs, 'N' - no rx label,
'P' - no rx intf label prot, 'p' - premature termination of LSP,
'R' - transit router, 'I' - unknown upstream index,
'X' - unknown return code, 'x' - return code 0

Type escape sequence to abort.

0 57.57.57.7 MRU 8986 [Labels: 24013 Exp: 0]
L 1 57.57.57.5 MRU 8986 [Labels: implicit-null/24012 Exp: 0/0] 11 ms
L 2 35.35.35.3 MRU 8986 [Labels: 24010 Exp: 0] 8 ms
L 3 13.13.13.1 MRU 8986 [Labels: 24010 Exp: 0] 6 ms
L 4 12.12.12.2 MRU 8986 [Labels: 24012 Exp: 0] 10 ms
L 5 24.24.24.4 MRU 8986 [Labels: implicit-null/24013 Exp: 0/0] 13 ms
L 6 46.46.46.6 MRU 8986 [Labels: implicit-null Exp: 0] 16 ms
! 7 68.68.68.8 19 ms
RP/0/RP0/CPU0:R1#

My question, how to make the MPLS TE tunnel establish over inter AS MPLS TE?

Fyi. I use explicit path with loose for all router id.

And from the perspective MPLS TE topology from R1 only show router id R1 and R2 only.

I have read in Cisco doc for similar use case, in IOS use MPLS traffic engineering passive interface in asbr. How about in IOS XR because I use IOSXR 6.5.3

Thank you

Fraedi

[M02@rt37]

Hello @fraedi-hangga 

RSVP is configured everywhere along all the path ? or not because all MPLS-TE LSPs have zero bandwidth ?

[fraedi-hangga]

hello M02@rt37 

thanks for your response
yes, rsvp is configured allong all the path.
and i have set MPLS TE from R2 to R5 with loose path and use verbatim options and the MPLS TE establish (running well).
but from R1 to R6 is failed while i use the same configuration like R2 to R5 (use verbatim options also)

thank you

Fraedi

[MHM Cisco World]

RP/0/RP0/CPU0:R1#traceroute mpls ipv4 6.6.6.6/32 source 1.1.1.1
Fri Sep 5 06:50:47.703 UTC

Tracing MPLS Label Switched Path to 8.8.8.8/32, timeout is 2 seconds

Why this or it typo

MHM

[fraedi-hangga]

hi @MHM Cisco World ,
yes typo, its should be Tracing MPLS Label Switched Path to 6.6.6.6/32


Thanks 
Fraedi

[Harold Ritter]

Hi @fraedi-hangga ,

Having an end to end LSP between R1 and R6 does not mean you can set up an RSVP tunnel between these two devices.

RSVP-TE and SR-TE both require the full topology to be able to establish a tunnel between two devices. This requirement is pretty simple to achieve in one single AS, but a bit more cumbersome between different networks.

In SR-TE, this is normally done using a controller that has the full topology of the two domains.

Controllers are used in SR networks, not RSVP networks. 

If you want to set an end to end tunnel between to different AS, I would definitely recommend using SR-TE.

EDITED:

I originally missed the fact that you use the "verbatim" feature. This make it somewhat possible, but very static. I definitely think it would be better to use SR for such a scenario.

Could you please share the tunnel configuration from R1 and R2.

[fraedi-hangga]

hi @Harold Ritter 

thanks for the response,
our network is not ready yet for SR, so we go through with MPLS (Inter AS).is there any idea to achieve MPLS-TE in InterAS MPLS?

here's the tunnel configuration and status : 
R2 to R5
note : R2 loopback 2.2.2.2/32 and R5 loopback 5.5.5.5/32

RP/0/RP0/CPU0:R2#show mpls traffic-eng tunnels tabular
Fri Sep 5 16:02:42.083 UTC

Tunnel LSP Destination Source Tun FRR LSP Path
Name ID Address Address State State Role Prot
----------------- ----- --------------- --------------- ------ ------ ---- -----
tunnel-te100 2 5.5.5.5 2.2.2.2 up Inact Head Inact
RP/0/RP0/CPU0:R2#

RP/0/RP0/CPU0:R2#sh run int tunnel-te 100
Fri Sep 5 16:08:40.811 UTC
interface tunnel-te100
ipv4 unnumbered Loopback0
signalled-name MPLS-TE-R2_TO_R5
autoroute announce
!
destination 5.5.5.5
path-option 1 explicit name P-01 verbatim
!

RP/0/RP0/CPU0:R2#sh run explicit-path name P-01
Fri Sep 5 16:08:50.391 UTC
explicit-path name P-01
index 2 next-address loose ipv4 unicast 3.3.3.3 ->(Loopback R3)
index 3 next-address loose ipv4 unicast 11.11.11.11 ->(loopback Core-1)
index 4 next-address loose ipv4 unicast 4.4.4.4 ->(loopback R4)
index 5 next-address loose ipv4 unicast 5.5.5.5 ->(loopback R5)
!

R1 to R6
note: R1:1.1.1.1/32 R6:6.6.6.6/32

RP/0/RP0/CPU0:R1#show mpls traffic-eng tunnels tabular
Fri Sep 5 16:18:20.916 UTC

Tunnel LSP Destination Source Tun FRR LSP Path
Name ID Address Address State State Role Prot
----------------- ----- --------------- --------------- ------ ------ ---- -----
tunnel-te90 0 6.6.6.6 0.0.0.0 down Inact Head Inact

RP/0/RP0/CPU0:R1#sh run int tunnel-te 90
Fri Sep 5 16:18:28.311 UTC
interface tunnel-te90
ipv4 unnumbered Loopback0
signalled-name TE-R1_TO_R6
autoroute announce
!
destination 6.6.6.6
path-option 1 explicit name INTERAS-LSP verbatim
!

RP/0/RP0/CPU0:R1#sh run explicit-path name INTERAS-LSP
Fri Sep 5 16:18:36.938 UTC
explicit-path name INTERAS-LSP
index 1 next-address loose ipv4 unicast 2.2.2.2 ->(loopback R2)
index 2 next-address loose ipv4 unicast 3.3.3.3 ->(loopback R3)
index 3 next-address loose ipv4 unicast 11.11.11.11 ->(loopback Core-1)
index 4 next-address loose ipv4 unicast 4.4.4.4 ->(loopback R4)
index 5 next-address loose ipv4 unicast 5.5.5.5 ->(loopback R5)
index 6 next-address loose ipv4 unicast 6.6.6.6 ->(loopback R6)
!

RP/0/RP0/CPU0:R1#

thank you
Fraedi

[MHM Cisco World]

interAS MPLS TE using BGP label <<- this meaning BGP LU ?

[fraedi-hangga]

hi @MHM Cisco World 
thanks for your response,
yes correct, BGP-LU (i use EBGP-LU between R2 - ASBR3 and R5 - ASBR4)

for services running under the topology is fine,
i create l2vpn point-to-point from R1 to R6 is establish:

RP/0/RP0/CPU0:R1#show l2vpn xconnect group E-LAN
Fri Sep 5 16:40:25.483 UTC
Legend: ST = State, UP = Up, DN = Down, AD = Admin Down, UR = Unresolved,
SB = Standby, SR = Standby Ready, (PP) = Partially Programmed,
LU = Local Up, RU = Remote Up, CO = Connected

XConnect Segment 1 Segment 2
Group Name ST Description ST Description ST
------------------------ ----------------------------- -----------------------------
E-LAN XC_78 UP Gi0/0/0/2.13 UP 5.5.5.5 78 UP
----------------------------------------------------------------------------------------
RP/0/RP0/CPU0:R1#

RP/0/RP0/CPU0:R5#show l2vpn xconnect group E-LAN
Fri Sep 5 16:41:37.524 UTC
Legend: ST = State, UP = Up, DN = Down, AD = Admin Down, UR = Unresolved,
SB = Standby, SR = Standby Ready, (PP) = Partially Programmed,
LU = Local Up, RU = Remote Up, CO = Connected

XConnect Segment 1 Segment 2
Group Name ST Description ST Description ST
------------------------ ----------------------------- -----------------------------
E-LAN XC_78 UP Gi0/0/0/2.13 UP 1.1.1.1 78 UP
----------------------------------------------------------------------------------------
RP/0/RP0/CPU0:R5#

thanks,
Fraedi, #57736

[MHM Cisco World]

The traceroute you share lead me to solution 

Traceroute is wrong there are label abd implicit null...

So I check 

You need I think mple te stitching 

I.e.

mpls te in MPLS-A from routers to asbr 

Mpls te From asbr to asbr 

Mpls te in MPLS-B from asbr to other routers

MHM

[fraedi-hangga]

hello @MHM Cisco World ,

so i should create mpls te stiching
1. MPLS TE from R1 to ASBR-3
2. MPLS TE from ASBR3 to ASBR4
4. MPLS TE from ASBR4 to R6

let me do ya,and will inform soon

thanks,

Fraedi

[MHM Cisco World]

You need five TE 

R1 to R2 

R2 to ASBR3

ASBR3 to ASBR4 

ASBR4 to R5 

R5 to R6

Do that' save config close lab (to force mpls label to re-exchange)

MHM

[fraedi-hangga]

hi @MHM Cisco World ,

already do what you suggest: 

R1 to R2: MPLS-TE UP

R2 to ASBR3: MPLS-TE UP

ASBR3 to ASBR4: MPLS-TE UP

ASBR4 to R5: MPLS-TE UP

R5 to R6: MPLS-TE UP

Do that' save config close lab (to force mpls label to re-exchange) : done
R1 to R6 MPLS-TE still down, do shut no shut interface te already done also

RP/0/RP0/CPU0:R1#sh mpls traffic-eng tunnels down
Sat Sep 6 08:56:08.317 UTC

Name: tunnel-te90 Destination: 6.6.6.6 Ifhandle:0x14
Signalled-Name: TE-R1_TO_R6
Status:
Admin: up Oper: down Path: not valid Signalling: Down

path option 1, (verbatim) type explicit INTERAS-LSP
Last PCALC Error: Sat Sep 6 08:50:47 2025
Info: Path-option is skipped because it is held down
Last Signalled Error : Sat Sep 6 08:55:47 2025
Info: [2789] PathErr(24,5)-(Error: routing (24), Suberror: no route to dest (5)) at 57.57.57.5 -> IP P2P R2 to R3
G-PID: 0x0800 (derived from egress interface properties)
Bandwidth Requested: 0 kbps CT0
Creation Time: Fri Sep 5 09:37:17 2025 (23:18:51 ago)
Config Parameters:
Bandwidth: 0 kbps (CT0) Priority: 7 7 Affinity: 0x0/0xffff
Metric Type: TE (global)
Path Selection:
Tiebreaker: Min-fill (default)
Hop-limit: disabled
Cost-limit: disabled
Delay-limit: disabled
Delay-measurement: disabled
Path-invalidation timeout: 10000 msec (default), Action: Tear (default)
AutoRoute: enabled LockDown: disabled Policy class: not set
Forward class: 0 (not enabled)
Forwarding-Adjacency: disabled
Autoroute Destinations: 0
Loadshare: 0 equal loadshares
Auto-bw: disabled
Auto-Capacity: Disabled:
Fast Reroute: Disabled, Protection Desired: None
Path Protection: Not Enabled
BFD Fast Detection: Disabled
Reoptimization after affinity failure: Enabled
Soft Preemption: Disabled

Displayed 1 (of 2) heads, 0 (of 0) midpoints, 0 (of 0) tails
Displayed 0 up, 1 down, 0 recovering, 0 recovered heads
RP/0/RP0/CPU0:R1#

Thank you,
Fraedi

[Harold Ritter]

Hi @fraedi-hangga ,

If you made the tunnel work between R2 and R5, we might be able to help with the tunnel from R1 to R7. Can you please provide the relevant configs from all the routers in the path so we can try to determine what is misconfigured?

[fraedi-hangga]

HI @Harold Ritter ,
sorry for late reply, 
here's the complate configuration like my topology that i was share before

thanks,

Fraedi