MPLS Traffic Engineering (TE) OSPF Configuration

In the MPLS Traffic Engineering (TE) IS-IS Configuration lesson and other MPLS TE lessons, I use IS-IS as the IGP on the TE routers. In this lesson, we’ll use OSPF instead.

I’ll walk you through the entire configuration, but because I already explained in detail how to configure an MPLS TE network step-by-step, I’ll only focus on OSPF here. This is the topology we’ll use:

Routers PE1, P1, P2, P3, and PE2 are our MPLS core network. The CE1 and CE2 routers use regular IP routing. All routers are configured to use OSPF area 0 and MPLS is enabled on the interfaces. I use Cisco IOS Software, IOSv Software (VIOS-ADVENTERPRISEK9-M), Version 15.9(3)M4.

hostname CE1
!
ip cef
!
interface Loopback0
 ip address 1.1.1.1 255.255.255.255
!
interface GigabitEthernet0/0
 ip address 192.168.12.1 255.255.255.0
!
router ospf 1
 network 1.1.1.1 0.0.0.0 area 0
 network 192.168.12.0 0.0.0.255 area 0
!
end

hostname CE2
!
ip cef
!
interface Loopback0
 ip address 7.7.7.7 255.255.255.255
!
interface GigabitEthernet0/0
 ip address 192.168.67.7 255.255.255.0
!
router ospf 1
 network 7.7.7.7 0.0.0.0 area 0
 network 192.168.67.0 0.0.0.255 area 0
!
end

hostname P1
!
ip cef
!
interface Loopback0
 ip address 3.3.3.3 255.255.255.255
!
interface GigabitEthernet0/0
 ip address 192.168.23.3 255.255.255.0
 mpls ip
!
interface GigabitEthernet0/1
 ip address 192.168.36.3 255.255.255.0
 mpls ip
!
router ospf 1
 network 3.3.3.3 0.0.0.0 area 0
 network 192.168.23.0 0.0.0.255 area 0
 network 192.168.36.0 0.0.0.255 area 0
!
mpls ldp router-id Loopback0 force
!
end

hostname P2
!
ip cef
!
interface Loopback0
 ip address 4.4.4.4 255.255.255.255
!
interface GigabitEthernet0/0
 ip address 192.168.24.4 255.255.255.0
 mpls ip
!
interface GigabitEthernet0/1
 ip address 192.168.45.4 255.255.255.0
 mpls ip
!
router ospf 1
 network 4.4.4.4 0.0.0.0 area 0
 network 192.168.24.0 0.0.0.255 area 0
 network 192.168.45.0 0.0.0.255 area 0
!
mpls ldp router-id Loopback0 force
!
end

hostname P3
!
ip cef
!
interface Loopback0
 ip address 5.5.5.5 255.255.255.255
!
interface GigabitEthernet0/0
 ip address 192.168.56.5 255.255.255.0
 mpls ip
!
interface GigabitEthernet0/1
 ip address 192.168.45.5 255.255.255.0
 mpls ip
!
router ospf 1
 network 5.5.5.5 0.0.0.0 area 0
 network 192.168.45.0 0.0.0.255 area 0
 network 192.168.56.0 0.0.0.255 area 0
!
mpls ldp router-id Loopback0 force
!
end

hostname PE1
!
ip cef
!
interface Loopback0
 ip address 2.2.2.2 255.255.255.255
!
interface GigabitEthernet0/0
 ip address 192.168.12.2 255.255.255.0
!
interface GigabitEthernet0/1
 ip address 192.168.23.2 255.255.255.0
 mpls ip
!
interface GigabitEthernet0/2
 ip address 192.168.24.2 255.255.255.0
 mpls ip
!
router ospf 1
 network 2.2.2.2 0.0.0.0 area 0
 network 192.168.12.0 0.0.0.255 area 0
 network 192.168.23.0 0.0.0.255 area 0
 network 192.168.24.0 0.0.0.255 area 0
!
mpls ldp router-id Loopback0 force
!
end

hostname PE2
!
ip cef
!
interface Loopback0
 ip address 6.6.6.6 255.255.255.255
!
interface GigabitEthernet0/0
 ip address 192.168.67.6 255.255.255.0
!
interface GigabitEthernet0/1
 ip address 192.168.36.6 255.255.255.0
 mpls ip
!
interface GigabitEthernet0/2
 ip address 192.168.56.6 255.255.255.0
 mpls ip
!
router ospf 1
 network 6.6.6.6 0.0.0.0 area 0
 network 192.168.36.0 0.0.0.255 area 0
 network 192.168.56.0 0.0.0.255 area 0
 network 192.168.67.0 0.0.0.255 area 0
!
mpls ldp router-id Loopback0 force
!
end

Before we continue, let’s make sure we have a label-switched path (LSP) when we send traffic from CE1 to CE2:

CE1#traceroute 7.7.7.7 source 1.1.1.1 probe 1
Type escape sequence to abort.
Tracing the route to 7.7.7.7
VRF info: (vrf in name/id, vrf out name/id)
  1 192.168.12.2 1 msec
  2 192.168.23.3 [MPLS: Label 23 Exp 0] 4 msec
  3 192.168.36.6 [MPLS: Label 19 Exp 0] 3 msec
  4 192.168.67.7 4 msec

The LSP is working.

Configuration

Let’s configure this “regular” MPLS network into a network that supports MPLS TE. There are four main items we have to configure:

• Enable MPLS TE support:
• Configure OSPF to support MPLS TE.
• Configure RSVP.
• Configure a TE tunnel interface.

We configure these items on all MPLS routers where you want to use MPLS TE. Let’s get started.

Global

The global mpls traffic-eng tunnels command enables MPLS TE globally:

PE1, P1, P2, P3, and PE2
(config)#mpls traffic-eng tunnels

Interfaces

We have to enable MPLS TE support on all interfaces that connect the PE and P routers:

This is the configuration:

PE1 and PE2
(config)#interface range GigabitEthernet 0/1 - 2
(config-if-range)#mpls traffic-eng tunnels

P1, P2, and P3
(config)#interface range GigabitEthernet 0/0 - 1
(config-if-range)#mpls traffic-eng tunnels

That’s all you need.

OSPF

There are two things we need to configure for OSPF to support MPLS TE:

• Enable MPLS TE for the area.
• Configure the router ID.

Here’s how to do it:

PE1, PE2, P1, P2 & P3
(config)#router ospf 1
(config-router)#mpls traffic-eng area 0
(config-router)#mpls traffic-eng router-id loopback 0

RSVP

Let’s configure RSVP to use up to the interface bandwidth:

PE1 and PE2
(config)#interface range GigabitEthernet 0/1 - 2
(config-if-range)#ip rsvp bandwidth 1000000

P1, P2, and P3
(config)#interface range GigabitEthernet 0/0 - 1
(config-if-range)#ip rsvp bandwidth 1000000

Tunnel Interface

Let’s configure a tunnel interface between PE1 and PE2:

This is how you configure a tunnel interface:

PE1(config)#interface Tunnel 1
PE1(config-if)#ip unnumbered Loopback 0
PE1(config-if)#tunnel mode mpls traffic-eng 
PE1(config-if)#tunnel destination 6.6.6.6
PE1(config-if)#tunnel mpls traffic-eng bandwidth 750
PE1(config-if)#tunnel mpls traffic-eng path-option 1 dynamic

Verification

Everything is now configured. This network should be ready for MPLS TE. Let’s find out.