When TE tunnels are used to carry two types of traffic, the Configurable Path Calculation Metric for Tunnels enhancement allows you to tailor tunnel path selection to the requirements of each type of traffic.

For example, suppose certain tunnels are to carry voice traffic (which requires low delay) and other tunnels are to carry data. In this situation, you can use the TE link metric to represent link delay and do the following:

• Configure tunnels that carry voice to use the TE link metric set to represent link delay for path calculation.
• Configure tunnels that carry data to use the IGP metric for path calculation.

• Unless explicitly configured, the TE link metric for a given link is the IGP link metric. When the TE link metric is used to represent a link property that is different from cost/distance, you must configure every network link that can be used for TE tunnels with a TE link metric that represents that property by using the mpls traffic-eng administrative-weight command. Failure to do so might cause tunnels to use unexpected paths.
• You cannot configure MPLS Traffic Engineering over the logical GRE tunnel interface.
• MPLS traffic engineering supports only a single IGP process/instance. Multiple IGP processes/instances are not supported and MPLS traffic engineering should not be configured in more than one IGP process/instance.

The configurable path calculation metric feature is related to MPLS TE.

1.    Router(config)# ip cef

2.    Router(config)# mpls traffic-eng tunnels

To configure IS-IS for MPLS traffic engineering, perform the following steps.

Note	MPLS traffic engineering supports only a single IGP process/instance. Multiple IGP processes/instances are not supported and MPLS traffic engineering should not be configured in more than one IGP process/instance.

1.    Router(config)# router isis

2.    Router(config-router)# mpls traffic-eng level-1

3.    Router(config-router)# mpls traffic-eng level-2

4.    Router(config-router)# mpls traffic-eng router-id loopback 0

5.    Router(config-router)# metric-style wide

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    mpls traffic-eng area number

5.    mpls traffic-eng router-id loopback0

6.    exit

7.    exit

1.    Router(config)# interface interface

2.    Router(config-router)# mpls traffic-eng administrative-weight weight

1.    Router(config)# interface tunnel-interface

2.    Router(config-if)# ip unnumbered loopback0

3.    Router(config-if)# tunnel destination ip-address

4.    Router(config-if)# tunnel mode mpls traffic-eng

5.    Router(config-if)# tunnel mpls traffic-eng bandwidth bandwidth

6.    Router(config-if)# tunnel mpls traffic-eng path-option number {dynamic | explicit {name path-name | id path-number}} [lockdown]

Unless explicitly configured, the TE link metric type is used for tunnel path calculation. Two commands are provided for controlling the metric type to be used: an interface configuration command that specifies the metric type to be used for a particular TE tunnel and a global configuration command that specifies the metric type to be used for TE tunnels for which a metric type has not been specified by the interface configuration command.

To configure the metric type for tunnel path calculation, perform one or both of the following steps:

Router(config-if)# tunnel mpls traffic-eng path-selection metric {igp | te}

Router(config)# mpls traffic-eng path-selection metric {igp | te}

Note	If you do not enter either of the commands, the traffic engineering (te) metric is used.

Use the show mpls traffic-eng topology command, which displays TE and IGP metrics for each link, to verify that link metrics have been correctly configured for a network.

Router# show mpls traffic-eng topology
My_System_id: 1440.0000.0044.00 (isis  level-1)
IGP Id: 0090.0000.0009.00, MPLS TE Id:192.168.9.9 Router Node  (isis  level-1)
      link[0 ]:Nbr IGP Id: 0090.0000.0009.03, gen:7
          frag_id 0, Intf Address:10.0.0.99
          TE metric:100, IGP metric:48, attribute_flags:0x0     !!Note TE and IGP metrics
          physical_bw: 10000 (kbps), max_reservable_bw_global: 0 (kbps)
          max_reservable_bw_sub: 0 (kbps)
  .
.
.
      link[1 ]:Nbr IGP Id: 0055.0000.0055.00, gen:7
          frag_id 0, Intf Address:10.205.0.9, Nbr Intf Address:10.205.0.55
          TE metric:120, IGP metric:10, attribute_flags:0x0     !!Note TE and IGP metrics
          physical_bw: 155000 (kbps), max_reservable_bw_global: 500000 (kbps)
          max_reservable_bw_sub: 0 (kbps)
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Use the show mpls traffic-eng tunnels command, which displays the link metric used for tunnel path calculation, to verify that the desired link metrics are being used for each tunnel.

Router# show mpls traffic-eng tunnels
Name: te3640-17-c_t221              (Tunnel22) Destination: 192.168.100.22
  Status:
    Admin: up         Oper: up     Path: valid       Signalling: connected
    path option 1, type dynamic (Basis for Setup, path weight 10)
  Config Parameters:
    Bandwidth: 400 kps (Global)    Priority: 1  1   Affinity: 0x0/0xFFFF
    Metric Type: IGP                                            !!Note metric type
    AutoRoute:  enabled   LockDown: disabled  Loadshare: 0   bw-based
    auto-bw: disabled(0/115) 0  Bandwidth Requested: 0
.
.
.
Name: te3640-17-c_t222              (Tunnel33) Destination: 192.168.100.22
  Status:
    Admin: up         Oper: up     Path: valid       Signalling: connected
    path option 1, type dynamic (Basis for Setup, path weight 10)
  Config Parameters:
    Bandwidth: 200 kbps (Global)   Priority: 1  1   Affinity: 0x0/0xFFFF
    Metric Type: TE                                              !!Note metric type
    AutoRoute:  enabled   LockDown: disabled  Loadshare: 0   bw-based
    auto-bw: disabled(0/115) 0  Bandwidth Requested: 0
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