Configuring a Basal MPLS P Router
Problem
You appetite to set up the amount of an MPLS network.
Solution
For the P routers in the amount of the MPLS network, the primary claim is to accredit CEF and about-face on MPLS on anniversary of the interfaces that will be forwarding MPLS tagged packets. In this example, we accept additionally enabled OSPF as a activating acquisition agreement aural the MPLS core:
Router-P1#configure terminal
Enter agreement commands, one per line. End with CNTL/Z.
Router-P1(config)#ip cef
Router-P1(config)#mpls ip
Router-P1(config)#interface FastEthernet0/0
Router-P1(config-if)#description affiliation to Router-PE2
Router-P1(config-if)#ip abode 10.1.2.11 255.255.255.0
Router-P1(config-if)#mpls ip
Router-P1(config-if)#exit
Router-P1(config)#interface Serial0/0
Router-P1(config-if)#description affiliation to Router-PE1
Router-P1(config-if)#ip abode 10.1.1.14 255.255.255.252
Router-P1(config-if)#mpls ip
Router-P1(config-if)#exit
Router-P1(config)#interface Serial0/1
Router-P1(config-if)#description affiliation to Router-PE3
Router-P1(config-if)#ip abode 10.1.1.10 255.255.255.252
Router-P1(config-if)#mpls ip
Router-P1(config-if)#exit
Router-P1(config)#interface Loopback0
Router-P1(config-if)#ip abode 10.0.0.11 255.255.255.255
Router-P1(config-if)#exit
Router-P1(config)#router ospf 99
Router-P1(config-router)#router-id 10.0.0.11
Router-P1(config-router)#network 10.0.0.0 0.255.255.255 breadth 0
Router-P1(config-router)#exit
Router-P1(config)#end
Router-P1#
Discussion
There are several things to agenda in this example. Firstly, enabling MPLS is artlessly a amount of enabling CEF globally on the router with the ip cef command, and again enabling MPLS on anniversary interface with the mpls ip command:
Router-P1(config)#ip cef
Router-P1(config)#mpls ip
Router-P1(config)#interface FastEthernet0/0
Router-P1(config-if)#mpls ip
In some earlier references, the interface command for enabling MPLS on an interface is tag-switching ip instead of mpls ip. Both commands are accustomed on best 12.x IOS levels. All IOS levels up to and including Version 12.3 automatically carbon the new command into the old form. Added confusingly, some IOS devices, such as the Lightstream 1010, adapt the mpls ip command as the all-around command and tag-switching ip as the interface command. So, on these devices, you may anticipate that you accept enabled MPLS on the interface back you accept in actuality aloof re-enabled it globally. So you should amend your agreement afterwards you accept typed it to ensure that it is still what you intended.
We additionally agenda in casual that the all-around command, mpls ip, is about not required, as the router will advanced MPLS packets by absence back the interface akin command is enabled. However, we accept included this command actuality aloof in case the all-around forwarding behavior has been disabled. You can attenuate MPLS packet forwarding for the absolute router by artlessly entering the "no" anatomy of the all-around command:
Router-P1(config)#no mpls ip
The abutting affair to apprehension is that we accept enabled MPLS on a FastEthernet interface and two Serial interfaces. You can run MPLS on a actual advanced array of interface types. Later in this chapter, to save on concrete connections, we will configure MPLS on Ethernet subinterfaces to acquiesce us to use VLANs. MPLS additionally works able-bodied over ATM, as we will altercate in a consecutive recipe.
When you accredit MPLS on an interface, the router automatically starts attractive for LDP or TDP packets. Best Cisco accessories abutment both and will auto-sense which one their acquaintance is using, and best will run the Cisco proprietary TDP by default, but about-face to the accessible accepted LDP if they ascertain LDP packets advancing from the neighbor. So you about don't charge to anguish about which one you appetite to run, the router will automatically baddest the adapted protocol.
In the example, we are application OSPF as an Interior Gateway Agreement (IGP) aural the MPLS core. Remember that this MPLS amount is itself aloof an IP network, so we charge to administer acquisition information. You could in assumption use any acquisition agreement you accept for this purpose. However, some ATM switches, conspicuously the Lightstream 1010, alone abutment OSPF for use with MPLS, authoritative it the best accustomed best for the MPLS amount IGP. For added advice on OSPF, amuse accredit to Affiliate 8:
Router-P1(config)#interface Loopback0
Router-P1(config-if)#ip abode 10.0.0.11 255.255.255.255
Router-P1(config-if)#exit
Router-P1(config)#router ospf 99
Router-P1(config-router)#router-id 10.0.0.11
Router-P1(config-router)#network 10.0.0.0 0.255.255.255 breadth 0
Router-P1(config-router)#exit
It is a acceptable accepted convenance to use a absolute IP abode on the accessory for the OSPF router ID. This is because the OSPF Router-ID appears in the acquaintance display, and it is about abundant easier to troubleshoot problems with your IGP if you can do simple PING and Telnet tests to this address:
Router-P1#show ip ospf neighbor
Neighbor ID Pri State Dead Time Abode Interface
10.0.0.3 0 FULL/ - 00:00:32 10.1.1.9 Serial0/1
10.0.0.2 0 FULL/ - 00:00:31 10.1.1.13 Serial0/0
10.0.0.4 1 FULL/DR 00:00:36 10.1.2.4 FastEthernet0/0
Router-P1#
There are three advantageous commands for acceptance basal functionality of your MPLS P routers. The aboriginal artlessly shows you the cachet of all of your MPLS interfaces:
Router-P1#show mpls interfaces
Interface IP Tunnel Operational
FastEthernet0/0 Yes (tdp) No Yes
Serial0/0 Yes (tdp) No Yes
Serial0/1 Yes (tdp) No Yes
Router-P1#
In this example, you can see that the three interfaces that we configured for MPLS are all listed and flagged as "Operational."
The abutting command allows you to see advice about the LDP or TDP acquaintance relationships with anniversary of these neighbors:
Router-P1#show mpls ldp neighbor
Associate TDP Ident: 10.0.0.2:0; Local TDP Ident 10.0.0.11:0
TCP connection: 10.0.0.2.711 - 10.0.0.11.28185
State: Oper; PIEs sent/rcvd: 0/82; Downstream
Up time: 01:04:45
TDP analysis sources:
Serial0/0, Src IP addr: 10.1.1.13
Addresses apprenticed to associate TDP Ident:
10.0.0.2 10.1.1.2 10.1.1.13
Associate TDP Ident: 10.0.0.3:0; Local TDP Ident 10.0.0.11:0
TCP connection: 10.0.0.3.711 - 10.0.0.11.57014
State: Oper; PIEs sent/rcvd: 0/79; Downstream
Up time: 01:04:33
TDP analysis sources:
Serial0/1, Src IP addr: 10.1.1.9
Addresses apprenticed to associate TDP Ident:
10.0.0.3 10.1.1.9 10.1.1.6
Associate TDP Ident: 10.0.0.4:0; Local TDP Ident 10.0.0.11:0
TCP connection: 10.0.0.4.711 - 10.0.0.11.21206
State: Oper; PIEs sent/rcvd: 0/77; Downstream
Up time: 01:04:50
TDP analysis sources:
FastEthernet0/0, Src IP addr: 10.1.2.4
Addresses apprenticed to associate TDP Ident:
10.0.0.4 10.1.2.4
Router-P1#
This command is decidedly advantageous if the achievement of the appearance mpls interfaces command adumbrated that one or added interfaces were not operational. You can see in this achievement both the IP abode of the adjoining accessory and a Associate TDP ID. This associate ID amount comes from a Loopback interface, if one has been configured, and identifies the absolute device. This is decidedly advantageous in situations back you accept assorted links amid adjoining devices. You will additionally apprehension that this affectation includes the IP abode of the abutting interface on the adjoining device, as able-bodied as a account of all added addresses acclimated by this device.
This affectation can additionally be advantageous for what it doesn't include. If you are accepting agitation accepting an MPLS interface to become operational, you should analysis the TDP acquaintance command to see if the router has apparent any neighbors at all on this interface. If not, again you ability accept a affiliation problem, or conceivably the acquaintance is not appropriately configured for MPLS.
The third acutely advantageous command on MPLS P routers looks at the MPLS forwarding table :
Router-P1#show mpls forwarding-table
Local Outgoing Prefix Bytes tag Outgoing Abutting Hop
tag tag or VC or Tunnel Id switched interface
16 Pop tag 10.0.0.2/32 7697 Se0/0 point2point
17 Pop tag 10.1.1.0/30 0 Se0/0 point2point
18 Pop tag 10.0.0.3/32 6685 Se0/1 point2point
19 Pop tag 10.1.1.4/30 0 Se0/1 point2point
20 21 10.0.0.1/32 0 Se0/0 point2point
21 10.0.0.1/32 0 Se0/1 point2point
21 Pop tag 10.0.0.4/32 19700 Fa0/0 10.1.2.4
Router-P1#
This achievement shows you all of the MPLS tags that are currently in use and which interfaces they point to. It is about advantageous to attending at the "Outgoing interface" and "Next Hop" columns to ensure that a accustomed avenue prefix is demography the aisle that you expect.