MPLS TE Tunnel Line Protocol Down

[yuan]

We are trying to deploy MPLE TE by testing it out in a lab first.

However, we can't seem to bring the Tunnel interface up. What are could be some of the possible reasons that contribute to this??

Tunnel0 is up, line protocol is down

Hardware is Tunnel

Interface is unnumbered. Using address of Loopback0 (10.10.143.1)

MTU 1514 bytes, BW 9 Kbit, DLY 500000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation TUNNEL, loopback not set

Keepalive not set

Tunnel source UNKNOWN, destination 10.10.143.37

Tunnel protocol/transport Label Switching, key disabled, sequencing disabled

Checksumming of packets disabled, fast tunneling enabled

Last input never, output never, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 3

Queueing strategy: fifo

Output queue: 0/0 (size/max)

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

0 packets input, 0 bytes, 0 no buffer

Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

0 packets output, 0 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

Router#show mpls traffic-eng tunnel

Name: Router_t0 (Tunnel0) Destination: 10.10.143.37

Status:

Admin: up Oper: down Path: not valid Signalling: Down

no path options defined

Config Parameters:

Bandwidth: 10 kbps (Global) Priority: 7 7 Affinity: 0x0/0xFFFF

Metric Type: TE (default)

AutoRoute: enabled LockDown: disabled Loadshare: 10 bw-based

auto-bw: disabled

History:

Tunnel:

Time since created: 2 hours, 17 minutes

[Harold Ritter · Accepted solution]

From the output of the "show mpls traffic-eng tunnel" command, you didn't configure either a dynamic or explicit path. This will definitely prevent the tunnel from coming up.

Use the "tunnel mpls traffic-eng path-option" command to configure an explicit or dynamic path for the TE tunnel.

Let me know if I answered your question,

[yuan]

I added the statement "tunnel mpls traffic-eng path option 10 dynamic" but line protocol is still down.

We are connecting two 3660 back-to-back for testing by the way. Here is the entire configuration,

Router#show run full

Building configuration...

Current configuration : 2328 bytes

!

version 12.2

service timestamps debug datetime msec

service timestamps log datetime msec

no service password-encryption

!

hostname Router

!

logging queue-limit 100

!

ip subnet-zero

!

!

!

ip cef

mpls ldp logging neighbor-changes

mpls traffic-eng tunnels

!

!

!

!

!

!

!

!

!

no voice hpi capture buffer

no voice hpi capture destination

!

!

mta receive maximum-recipients 0

!

!

!

!

interface Loopback0

ip address 10.10.143.1 255.255.255.255

!

interface Tunnel0

ip unnumbered Loopback0

tunnel destination 10.10.143.37

tunnel mode mpls traffic-eng

tunnel mpls traffic-eng autoroute announce

tunnel mpls traffic-eng priority 7 7

tunnel mpls traffic-eng bandwidth 10

tunnel mpls traffic-eng path-option 10 dynamic

!

interface FastEthernet0/0

ip address 10.10.143.49 255.255.255.252

duplex auto

speed auto

mpls traffic-eng tunnels

tag-switching ip

ip rsvp bandwidth 1000

!

interface FastEthernet0/1

no ip address

shutdown

duplex auto

speed auto

!

interface ATM1/0

no ip address

shutdown

no atm ilmi-keepalive

!

interface Serial2/0

no ip address

shutdown

clockrate 2000000

!

interface Serial2/1

no ip address

shutdown

clockrate 2000000

!

interface Serial2/2

no ip address

shutdown

clockrate 2000000

!

interface Serial2/3

no ip address

shutdown

clockrate 2000000

!

interface Serial3/0

no ip address

shutdown

clockrate 2000000

!

interface Serial3/1

no ip address

shutdown

clockrate 2000000

!

interface Serial4/0

no ip address

shutdown

clockrate 2000000

!

interface Serial4/1

no ip address

shutdown

clockrate 2000000

!

interface Serial4/2

no ip address

shutdown

clockrate 2000000

!

interface Serial4/3

no ip address

shutdown

clockrate 2000000

!

router ospf 1

mpls traffic-eng router-id Loopback0

mpls traffic-eng area 0

log-adjacency-changes

network 10.10.143.0 0.0.0.3 area 0

network 10.10.143.48 0.0.0.3 area 0

!

ip http server

ip classless

ip route 0.0.0.0 0.0.0.0 Tunnel0

ip route 10.10.143.50 255.255.255.255 Tunnel0

!

!

!

!

!

!

call rsvp-sync

!

!

mgcp profile default

!

!

!

dial-peer cor custom

!

!

!

!

line con 0

transport preferred lat pad v120 lapb-ta mop telnet rlogin udptn

transport output lat pad v120 lapb-ta mop telnet rlogin udptn

line aux 0

transport preferred lat pad v120 lapb-ta mop telnet rlogin udptn

transport output lat pad v120 lapb-ta mop telnet rlogin udptn

line vty 0 4

login

!

!

end

[Harold Ritter]

Could you join the config of the tail end router and also a new :show mpls traf tu tu0".

Thanks,

[dknov]

Hi,

One observation so far. You have a static /32 which goes through a tunnel interface, so it's like a 'chicken and the egg'. To build a tunnel you need an IP path first (to signal RSVP which is UDP based).

Try removing the /32 and see if it helps.

David

[Harold Ritter]

It is false to believe that you need a route to the tunnel destination in the RIB for the tunnel to come up.

The path taken by the PATH message to the tunnel tailend is calculated on the headend and specified in the Explicit Route Object. The ERO is built from the TE information received from isis or ospf (isis TE extensions or ospf opaque LSAs).

Each router in the path will process the PATH message and then forward according to the ERO. The routing table is not referenced in this process.

Hope this help,

[dknov]

Hi,

I agree the PATH messages are passed on based on ERO field, however doesn't a router need to know through which interface to send the PATH massage to get to next IP in ERO?

If so, by configuring a /32 static via Tunnel you are basically saying to the router that PATH message

should be forwarded via Tunnel to the next IP in ERO field, however Tunnel is not up.....

I might be mistaken (and we need "show ip route" to verify) because without Tunnel being up, this /32 will never make it to a routing table, so no confision will bemade and connected /30 will indeed make PATH messages take a right way through a physical interface.

David

[Harold Ritter]

David,

Each hop in the ERO is a directly connected interface for the respective routers in the PATH calculated by CSPF. There is really no need to ever reference the RIB to forward a PATH message.

Having a /32 for the tunnel destination pointing at the tunnel interface would not prevent the tunnel from coming up. It is commonly used instead of "autoroute annonce" when you want to limit the traffic going through the TE tunnel.

Hope this helps,