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Configuration Tasks

Configuring an MPLS network consists of the following sets of tasks:

In this section, pure MPLS configuration tasks are distinguished from LDP and RSVP-TE configuration tasks.

Many users find it convenient to configure MPLS by completing the tasks in each category before moving to the next category. However, you do not have to complete the tasks in the listed order.

The type of network you want to implement determines which sets of tasks you must complete, as indicated in Table 25.




Table 25: Configuration Tasks by Type of Network 
Task Set
Traffic Engineering Network
Topology-Driven Network (Best-Effort, Hop-by-Hop, LDP)

Global

Yes

Yes

Interface Profile

Optional

Optional

Interface

Yes

Yes

Tunnel

Yes

No

Tunnel Profile

Yes

No

While the basic configuration tasks are covered in this section, additional configuration tasks are described in later sections of this chapter.

Global Configuration Tasks

Complete these tasks to configure a virtual router as an LSR. You perform these commands in Global Configuration mode. The following sequence is arbitrary; you can perform these tasks in any order.

After you have completed the global configuration tasks, proceed to LDP Interface Profile Configuration Tasks and Command.

MPLS Tasks and Commands

In a typical network, you perform only the first task. You might also perform the optional configuration tasks, but typically do not need to do so.

  1. Enable MPLS on a virtual router.
  2. host1(config)#mpls
    
    
    
  3. (Optional) Configure the time-to-live field placed in the MPLS header when a label is first added to an IP packet.
  4. host1(config)#mpls ip propagate-ttl forwarded
    
    
    
  5. (Optional) Configure the tunneling model for differentiated services. See MPLS and Differentiated Services for more information and command descriptions.
  6. host1(config)#mpls tunnel-model uniform
    
    
    
  7. (Optional) Specify whether to use the TOS value or the UPC value of the packet as the value of the EXP bits when the router acts as an LER. See MPLS and Differentiated Services for more information and command descriptions.
  8. host1(config)#mpls copy-upc-to-exp
    
    
    
  9. (Optional) Specify whether the EXP bits for VPN MPLS labels can be modified by EXP bit mapping or by policy for differentiated services. See MPLS and Differentiated Services for more information and command descriptions.
  10. host1(config)#mpls preserve-vpn-exp
    
    
    
  11. (Optional) Specify whether to create dynamic IP interfaces on top of MPLS major interfaces and optionally what profile to use for them.
  12. host1(config)#mpls create-dynamic-interfaces ip on-major-interfaces
    
    
    
  13. (Optional) Remove and then reestablish existing dynamic IPv4 and IPv6 interfaces on top of MPLS major interfaces.
  14. host1#clear mpls dynamic-interfaces on-major-interfaces
    

clear mpls dynamic-interfaces on-major-interfaces

mpls

mpls create-dynamic-interfaces

mpls ip propagate-ttl

You can specify the types of packets to be hidden from traceroute by using the following keywords with the no version:

You can subsequently specify these keywords with the affirmative version of the command to stop hiding the packets from traceroute.

LDP Tasks and Commands

Typically, you do not configure anything for LDP at the global level, but you can perform the following optional tasks.

  1. (Optional) Enable LDP and topology-driven LSP. Any LDP-related command creates LDP implicitly, negating the need to issue this command.
  2. host1(config)#mpls ldp
    
    
    
  3. (Optional) Configure the redistribution of IGP routes to LDP.
  4. host1(config)#mpls ldp redistribute ospf route-map boston5
    
    
    
  5. (Optional) Configure lists of peer addresses that targeted hello messages are sent to or accepted from.
  6. host1(config)#mpls ldp targeted-hello send list 10.21.5.87
    
    host1(config)#mpls ldp targeted-hello receive list 192.168.45.25
    
    
    
  7. (Optional) Configure the hold time and interval values for targeted hello messages used in LDP extended discovery.
  8. host1(config)#mpls ldp targeted-hello holdtime 90
    
    host1(config)#mpls ldp targeted-hello interval 30
    
    
    
  9. (Optional) Configure LDP session retry values.
  10. host1(config)#mpls ldp session retry-time 2
    
    host1(config)#mpls ldp session retries 1800
    
    
    
  11. (Optional) Configure the period that LDP negotiates with its peer for which the LDP session is maintained in the absence of any LDP messages.
  12. host1(config)#mpls ldp session holdtime 1800
    
    
    
  13. (Optional) Configure the interval at which LDP sends session keepalive messages.
  14. host1(config)#mpls ldp session keepalive-time 180
    
    
    
  15. (Optional) Specify an IP address to be advertised to peers as the transport address in discovery hello messages.
  16. host1(config)#mpls ldp discovery transport-address 192.168.34.2
    
    
    
  17. (Optional) Configure independent control as the method of label distribution that LDP uses.
  18. host1(config)#mpls ldp independent-control
    
    
    
  19. (Optional) Configure LDP to advertise the explicit null label or a non-null label for the egress router to achieve ultimate hop popping.
  20. host1(config)#mpls ldp egress-label explicit-null
    
    
    

For topology-driven LSPs, perform the following LDP configuration tasks.

  1. (Optional) Configure the LSR to create topology-driven LSPs. Enabling LDP automatically creates topology-driven LSPs.
  2. host1(config)#mpls topology-driven-lsp
    
    
    
  3. (Optional) Specify filters for the routes and peers to which the labels are advertised.
  4. host1(config)#mpls ldp advertise-labels host-only
    
    
    
  5. (Optional) Specify the LSPs to be put into the IP routing table for forwarding plain IP traffic.

    NOTE: This step is not optional if you are using a topology-driven network to forward plain IP packets.


  6. host1(config)#ldp ip-forwarding host-only
    
    
    
  7. (Optional) Establish a policy governing the distribution of incoming LDP labels.
  8. host1(config)#mpls ldp advertise-labels for boston1
    
    
    
  9. (Optional) Remove and then reestablish existing LDP LSPs.
  10. host1#clear mpls ldp
    
    
    

clear mpls ldp

mpls ldp

mpls ldp advertise-labels

In this example, suppose the LSR receives a label for destination 10.10.11.12. If net25 specifies 10.10.11.12, then the access list action—permit or deny—is taken with the destination. If the action is permit, the peer that the label is advertised to is subject to the access list euro3. If net25 does not include 10.10.11.12, the LSR attempts to match it against boston1. If 10.10.11.12 is present in that access list, the specified action is taken for all peers. If boston1 does not include the destination, the label is not advertised to any peer.

mpls ldp discovery transport-address

mpls ldp egress-label

mpls ldp independent-control

mpls ldp ip-forwarding

mpls ldp profile

mpls ldp redistribute

mpls ldp session holdtime

mpls ldp session keepalive interval

mpls ldp session retries

mpls ldp session retry-time

mpls ldp targeted-hello holdtime

mpls ldp targeted-hello interval

mpls ldp targeted-hello receive list

mpls ldp targeted-hello send list

mpls topology-driven-lsp

RSVP-TE Tasks and Commands

Typically, you do not configure anything for RSVP-TE at the global level, but you can perform the following optional tasks.

  1. (Optional) Enable RSVP-TE. Any RSVP-TE–related command creates RSVP-TE implicitly, negating the need to issue this command.
  2. host1(config)#mpls rsvp
    
    
    
  3. (Optional) Configure retry timer options globally (to apply to all tunnels) to set up an LSP after a setup failure. You can also configure timers for a specific tunnel; see Tunnel Configuration Tasks.
  4. host1(config)#mpls lsp retries 35
    
    host1(config)#mpls lsp retry-time 55
    
    
    
  5. (Optional) Configure the interval at which the bandwidth values are flooded.
  6. host1(config)#mpls traffic-eng link-management timers periodic-flooding 10
    
    
    
  7. (Optional) Configure reoptimization—How often MPLS searches for better paths for the tunnel.
  8. host1(config)#mpls reoptimize timers frequency 180
    
    
    

You can also force an immediate search for better paths for all existing LSPs.

host1#mpls reoptimize

  1. (Optional) Enable refresh reduction and message bundling.
  2. host1(config)#mpls rsvp refresh-reduction
    
    host1(config)#mpls rsvp message-bundling
    
    
    
  3. (Optional) Configure the egress router to advertise the explicit null label.
  4. host1(config)#mpls rsvp egress-label explicit-null
    

mpls lsp no-route retries

mpls lsp no-route retry-time

mpls lsp retries

mpls lsp retry-time

mpls reoptimize

mpls reoptimize timers frequency

mpls rsvp

mpls rsvp egress-label

mpls rsvp message-bundling

mpls rsvp profile

mpls rsvp refresh-reduction

mpls traffic-eng link-management timers periodic-flooding

BGP Tasks

For BGP global configuration tasks, see Chapter 1, Configuring BGP Routing and Chapter 3, Configuring BGP-MPLS Applications.

LDP Interface Profile Configuration Tasks and Command

Complete these optional tasks to configure the label distribution options. Creating or accessing an interface profile places the CLI in LDP Configuration mode. When you have completed the interface profile configuration tasks, proceed to the section Interface Configuration Tasks.

  1. Access the desired profile configuration mode.
  2. host1(config)#mpls ldp interface profile ldp5
    
    
    
  3. Configure interface profile settings, changing the values from the implicit default values.
  4. host1(config-ldp)#hello hold-time 30
    
    host1(config-ldp)#hello interval 10
    
    
    

hello hold-time

hello interval

RSVP Interface Profile Configuration Tasks and Commands

Complete these optional tasks to configure the label distribution options. Creating or accessing an interface profile places the CLI in RSVP Configuration mode. When you have completed the interface profile configuration tasks, proceed to the section Interface Configuration Tasks.

  1. Access the desired profile configuration mode.
  2. host1(config)#mpls rsvp interface profile rsvp4
    
    
    
  3. Configure interface profile settings, changing the values from the implicit default values.
  4. host1(config-rsvp)#refresh-period
    
    host1(config-rsvp)#cleanup-timeout-factor
    
    
    

cleanup-timeout-factor

refresh-period

Interface Configuration Tasks

These tasks are performed at the major interface over which you want to run MPLS. Creating or accessing an interface places the CLI in Interface Configuration mode. You can then configure MPLS options on that interface. The following sequence is arbitrary; you can perform these tasks in any order.

NOTE: Loop detection is always enabled in the JUNOSe MPLS implementation.


When you have completed the interface configuration tasks, proceed to Tunnel Configuration Tasks.

MPLS Tasks and Commands

  1. Enable MPLS on the interface.
  2. host1(config-if)#mpls
    
    
    

or

host1(config-if)#no mpls disable

  1. (Optional) Configure the interface label space with the VPI and VCI ranges.
  2. host1(config-if)#mpls atm vpi range 10 200
    
    host1(config-if)#mpls atm vci range 33 4000
    
    
    

Only ATM AAL5 interfaces support the interface label space.

  1. (Optional) Specify an interface for signaling for an MPLS major interface in the interface label space.
  2. host1(config-if)#mpls signaling-interface atm 4/0.5
    
    
    

mpls

mpls atm vci range

mpls atm vpi range

mpls disable

mpls signaling-interface

LDP Tasks and Command

  1. Start LDP on the interface.
  1. (Optional) Suppress transmission of link hello messages to all LSRs.
  2. host1(config-if)#mpls ldp link-hello disable
    

mpls ldp disable

mpls ldp link-hello disable

mpls ldp profile

RSVP-TE Tasks and Commands

  1. Start RSVP-TE on the interface.
  1. (Optional) Configure total bandwidth available on the interface.
  2. host1(config-if)#bandwidth 8192
    
    
    
  3. (Optional) Configure total bandwidth reservable for MPLS on the interface.
  4. host1(config-if)#mpls bandwidth 4096
    
    
    
  5. (Optional) Specify thresholds that trigger bandwidth flooding when crossed by an increase or decrease in the total reservable bandwidth.
  6. host1(config-if)#mpls traffic-eng flood thresholds up 15
    
    host1(config-if)#mpls traffic-eng flood thresholds down 15
    
    
    
  7. (Optional) Specify the resource attributes for the interface so that tunnels can discriminate among interfaces.
  8. host1(config-if)#mpls traffic-eng attribute-flags 0x000001f9
    
    
    
  9. (Optional) Configure an administrative weight for the interface that overrides the weight assigned by the IGP.
  10. host1(config-if)#mpls traffic-eng administrative-weight 25
    
    
    

bandwidth

mpls bandwidth

mpls rsvp disable

mpls rsvp profile

mpls traffic-eng administrative-weight

mpls traffic-eng attribute-flags

mpls traffic-eng flood thresholds

Tunnel Configuration Tasks

Complete the following tasks to configure a tunnel interface. Configure the tunnel endpoint last; anything configured after the tunnel endpoint does not take effect until the tunnel is brought up the next time. You can perform all other tasks in any order.

NOTE: Tunnel configuration tasks are relevant only for traffic engineering networks.


  1. Create the MPLS tunnel interface.
  2. host1(config)#interface tunnel mpls:boston
    
    
    
  3. (Optional) Configure the LSP to announce its endpoint to an IGP (sometimes referred to as registering the endpoint).
  4. host1(config-if)#tunnel mpls autoroute announce isis
    
    
    
  5. (Optional) Specify a tunnel metric to be used by an IGP in its SPF calculation.
  6. host1(config-if)#tunnel mpls autoroute metric absolute 100
    
    
    
  7. (Optional) Configure the path options used for the tunnel.
  8. host1(config-if)#tunnel mpls path-option 3 dynamic isis
    
    
    
  9. (Optional) Configure the bandwidth required for the tunnel.
  10. host1(config-if)#tunnel mpls bandwidth 1240
    
    
    
  11. (Optional) Configure preemption hold or setup priority.
  12. host1(config-if)#tunnel mpls traffic-eng priority 4 4
    
    
    
  13. (Optional) Configure resource class affinity.
  14. host1(config-if)#tunnel mpls traffic-eng affinity 0x1100 mask 0xFFFF
    
    
    
  15. (Optional) Configure retry timers options to apply to a specific tunnel to set up an LSP after a setup failure.
  16. host1(config-if)#tunnel mpls no-route retries 100
    
    host1(config-if)#tunnel mpls no-route retry-time 45
    
    host1(config-if)#tunnel mpls retries 250
    
    host1(config-if)#tunnel mpls retry-time 65 
    
    
    
  17. (Optional) Associate a text description with the tunnel.
  18. host1(config-if)#tunnel mpls description southshore
    
    
    
  19. Configure the tunnel endpoint.
  20. host1(config-if)#tunnel destination 10.12.21.5
    

interface tunnel

tunnel destination

tunnel mpls affinity

tunnel mpls autoroute announce

tunnel mpls autoroute metric

tunnel mpls bandwidth

The QoS profile creates a scheduler node at the LSP level, with a scheduler profile that has an assured rate corresponding to the reserved bandwidth.

The QoS profile also creates queues above the scheduler node so that traffic of a particular class will be subject to the scheduler node. If no queue are created at the LSP level for a particular class, the traffic of that class enters that class's queue at a lower level, bypassing the bandwidth reservation enforcement.

tunnel mpls description

tunnel mpls no-route retries

tunnel mpls no-route retry-time

tunnel mpls path-option

tunnel mpls priority

If insufficient resources exist for a new LSP to be established, its setup priority is evaluated against the hold priorities of existing LSPs. If the new LSP has a higher priority, it preempts the resources from the lower-priority existing LSP(s) and is established.

tunnel mpls retries

tunnel mpls retry-time

Tunnel Profile Configuration Tasks

If you anticipate having multiple tunnels to share the same configuration, you can reduce your configuration time by using tunnel profiles to configure your tunnels. When you create a tunnel profile, you can use most of the commands presented in Tunnel Configuration Tasks; see that section for descriptions of the commands.

In the profile, configure the tunnel endpoint last; anything configured after the tunnel endpoint does not take effect until the tunnel is brought up the next time. You can perform all other tasks in any order.

NOTE: Tunnel profile configuration tasks are relevant only for traffic engineering networks.


To configure a tunnel profile:

  1. Enter Tunnel Profile Configuration mode.
  2. host1(config)#mpls tunnels profile Lisbon
    
    
    
  3. (Optional) Configure the LSP to announce its endpoint to an IGP.
  4. host1(config-tunnelprofile)#tunnel mpls autoroute announce isis
    
    
    
  5. (Optional) Specify a tunnel metric to be used by an IGP in its SPF calculation.
  6. host1(config-tunnelprofile)#tunnel mpls autoroute metric absolute 100
    
    
    
  7. (Optional) Configure the path options used for the tunnel.
  8. host1(config-tunnelprofile)#tunnel mpls path-option 3 dynamic isis
    
    
    
  9. (Optional) Configure the bandwidth required for the tunnel.
  10. host1(config-tunnelprofile)#tunnel mpls bandwidth 1240
    
    
    
  11. (Optional) Configure preemption hold or setup priority.
  12. host1(config-tunnelprofile)#tunnel mpls priority 4 4
    
    
    
  13. (Optional) Configure resource class affinity.
  14. host1(config-tunnelprofile)#tunnel mpls affinity 0x1100 mask 0xFFFF
    
    
    
  15. (Optional) Configure retry timers options to apply to a specific tunnel to set up an LSP after a setup failure.
  16. host1(config-tunnelprofile)#tunnel mpls no-route retries 100
    
    host1(config-tunnelprofile)#tunnel mpls no-route retry-time 45
    
    host1(config-tunnelprofile)#tunnel mpls retries 250
    
    host1(config-tunnelprofile)#tunnel mpls retry-time 65 
    
    
    
  17. (Optional) Associate a text description with the tunnel.
  18. host1(config-tunnelprofile)#tunnel mpls description southshore
    
    
    
  19. Configure the tunnel endpoint.

All tunnels to the specified destination(s) are configured with the profile settings.

When an endpoint is dynamically learned from the specified routing protocol, MPLS searches its tunnel profiles for a match. The dynamic tunnel is established using the settings from the first matching profile.

mpls tunnels profile

tunnel destination


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