MPLS-TE Basic Config

For MPLS-TE, there are two steps. One: create a tunnel between head end LSR and tail end LSR.

Second: Forward traffic via tunnel which now act as virtual link.

Here, configuration for tunnel creation is described. Steps to enable MPLS-TE:

1) Enable MPLS  TE globally;

R0(config)#mpls traffic-eng tunnels

2)  Enable the interface with MPLS TE and allocate BW for RSVP;

R0(config)#int fa 0/1

R0(config-if)#mpls traffic-eng tunnels
R0(config-if)#ip rsvp bandwidth 5000

The default maximum bandwidth is 75% of interface BW and a single flow can reserve all reservable bandwidth.

NOte: if we try to enabled the mpls te on interface before enabling globally, below message would be noted;
R2(config-if)#mpls traffic-eng tunnels
LSP tunnels not enabled — could not enable RSVP!
R2(config-if)#

In above diagram, a tunnel 03 has to be created from R0 to R3.


3) Enable OSPF/ISIS protocol in the MPLS domain with TE capability;
R0#show run | sec ospf
router ospf 1
mpls traffic-eng router-id Loopback0
mpls traffic-eng area 0
router-id 100.100.100.100
log-adjacency-changes
network 12.1.1.0 0.0.0.255 area 0
R0#
4) When OSPF neigborship is UP make sure that Opaque LSA is supported(optional)
R0#show ip ospf 1
Routing Process “ospf 1” with ID 100.100.100.100
Start time: 00:33:19.688, Time elapsed: 00:07:02.660
Supports only single TOS(TOS0) routes
Supports opaque LSA
The “O” bit in the option field of LSA header is set to denote the opaque LSA support.

5) Check the OSPF database whether the opaque LSAs are present (optional)

R0#show ip ospf database opaque-area adv-router 3.3.3.3

OSPF Router with ID (100.100.100.100) (Process ID 1)

Type-10 Opaque Link Area Link States (Area 0)

LS age: 1576
Options: (No TOS-capability, DC)
LS Type: Opaque Area Link
Link State ID: 1.0.0.0
Opaque Type: 1
Opaque ID: 0
Advertising Router: 3.3.3.3
LS Seq Number: 80000006
Checksum: 0xEF2D
Length: 132
Fragment number : 0

MPLS TE router ID : 3.3.3.3

Link connected to Broadcast network
Link ID : 10.1.1.2
Interface Address : 10.1.1.2
Admin Metric : 10   <<<<<<< same as IGP metric
Maximum bandwidth : 1250000  <<<<<<< Interface BW
Maximum reservable bandwidth : 6250000  <<<<<< BW allocated for RSVP
Number of Priority : 8
Priority 0 : 6250000     Priority 1 : 6250000
Priority 2 : 6250000     Priority 3 : 6250000
Priority 4 : 6250000     Priority 5 : 6250000
Priority 6 : 6250000     Priority 7 : 6250000
Affinity Bit : 0x0
IGP Metric : 10

Number of Links : 1

R0#

6) Configure tunnel interface;

R0#show run int tu 3
Building configuration…

Current configuration : 253 bytes
!
interface Tunnel3
ip unnumbered Loopback0
tunnel destination 3.3.3.3
tunnel mode mpls traffic-eng
tunnel mpls traffic-eng priority 7 7
tunnel mpls traffic-eng bandwidth  100
tunnel mpls traffic-eng path-option 2 dynamic
no routing dynamic
end

7) Make sure on the path  from head end to tail end LSR, some interface bandwidth are reserved for RSVP, using  “ip rsvp bandwidth”.

8) Verify the tunnel is operationally UP (optional)

R0#show mpls traffic-eng tunnels tunnel 03

Name: R0_t3                               (Tunnel3) Destination: 3.3.3.3
Status:
Admin: up         Oper: up     Path: valid       Signalling: connected

path option 2, type dynamic (Basis for Setup, path weight 11)

Config Parameters:
Bandwidth: 100      kbps (Global)  Priority: 7  7   Affinity: 0x0/0xFFFF
Metric Type: TE (default)
AutoRoute:  disabled  LockDown: disabled  Loadshare: 100      bw-based
auto-bw: disabled

InLabel  :  –
OutLabel : FastEthernet0/1, 16
RSVP Signalling Info:
Src 100.100.100.100, Dst 3.3.3.3, Tun_Id 3, Tun_Instance 17
RSVP Path Info:
My Address: 12.1.1.1
Explicit Route: 12.1.1.2 10.1.1.1 10.1.1.2 3.3.3.3
Record Route:  NONE
Tspec: ave rate=100 kbits, burst=1000 bytes, peak rate=100 kbits
RSVP Resv Info:
Record Route:  NONE
Fspec: ave rate=100 kbits, burst=1000 bytes, peak rate=100 kbits
Shortest Unconstrained Path Info:
Path Weight: 11 (TE)
Explicit Route: 12.1.1.1 12.1.1.2 10.1.1.1 10.1.1.2
3.3.3.3
History:
Tunnel:
Time since created: 28 minutes, 59 seconds
Time since path change: 11 minutes, 24 seconds
Current LSP:
Uptime: 11 minutes, 24 seconds
Prior LSP:
ID: path option 2 [2]
Removal Trigger: tunnel shutdown
R0#
HTH,
VEnkat

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