H-VPLS N-PE Redundancy for MPLS Access

This chapter contains the following sections:

H-VPLS

The H-VPLS N-PE Redundancy for MPLS Access feature enables two network provider edge (N-PE) devices to provide failover services to a user provider edge (U-PE) device in a hierarchical virtual private LAN service (H-VPLS). Redundant N-PE devices increase stability and reliability by protecting against link and node failures. If a failure occurs in the network that disables one N-PE device from transmitting data, the other N-PE device takes over.

Table 1. Feature History Table

Feature name

Release information

Feature description

H-VPLS N-PE Redundancy for MPLS Access

Release 17.18.2

This feature enables a U‑PE to connect to two N‑PEs using active/backup pseudowires, delivering rapid switchover on link or node failure without service reconfiguration.

Prerequisites for H-VPLS

  • Configure your H-VPLS network.

  • Enable the MPLS Traffic Engineering-Fast Reroute feature in the MPLS core to improve convergence.

  • Enable the L2VPN Pseudowire Redundancy feature on the U-PE devices for MPLS access.

Restrictions for H-VPLS

  • You cannot use this feature with the VPLS Autodiscovery feature on pseudowires that connect to U-PE devices. When you create the virtual private LAN service (VPLS), manually create the virtual forwarding interface (VFI).

  • You cannot configure more than one pseudowire to carry the bridge protocol data unit (BPDU) information between the network provider edge (N-PE) devices.

  • You cannot configure a local loopback address as a neighbor when you configure the H-VPLS N-PE Redundancy feature on N-PE devices.

  • Only two N-PE devices can be connected to each U-PE device.

H-VPLS N-PE redundancy with MPLS access based on pseudowire redundancy

For H-VPLS Redundancy with MPLS Access, the MPLS network uses redundant pseudowires. These pseudowires connect the MPLS network to N-PE devices in the VPLS core.

As shown in the figure, a primary pseudowire carries data between the U-PE and N-PE devices. If the U-PE path fails, a backup pseudowire and redundant N-PE device activate to continue data transport.

Figure 1. H-VPLS N-PE redundancy for MPLS access based on pseudowire Redundancy

Configuration of H-VPLS N-PE Redundancy for MPLS Access

Specify the devices in the layer 2 VPN VFI

Before you begin

Ensure that the device is in configuration mode.

Procedure

Step 1

Use the l2vpn vfi context name command to establish a L2VPN VFI between two or more separate networks, and enter L2VFI configuration mode.

Example:

Device(config)# l2vpn vfi context VPLS-10

Step 2

Use the vpn id vpn id command to set a VPN ID on the VPLS instance.

Example:

Device(config-vfi)# vpn id 10

  • Use the same VPN ID for the PE devices that belong to the same VPN.

  • Make sure the VPN ID is unique for each VPN in the service provider network. The range is from 1 to 4294967295.

Step 3

Use the member ip address encapsulation mpls command to specify the device that forms a point-to-point L2VPN VFI connection.

Example:

Device(config-vfi)# member 102.102.102.102 encapsulation mpls

  • ip-address : IP address of the VFI neighbor (the N-PE device).

  • encapsulation mpls: specifies MPLS as the data encapsulation method.

Step 4

Use the exit command to return to global configuration mode.

Example:

Device(config-vfi)# exit

Step 5

Use the bridge domain bridge domain command to configure components on a bridge domain, and enter bridge-domain configuration mode.

Example:

Device(config)# bridge domain 10

Step 6

Use the member vfi vfi-name command to configure the VFI member in the bridge-domain.

Example:

Device(config-bdomain)# member vfi VPLS-10

Step 7

Use the member ip-address vc-id encapsulation mpls command to specify the device that forms a point-to-point L2VPN VFI connection.

Example:

Device(config-vfi)# member 105.105.105.105 10  encapsulation mpls

  • ip-address : IP address of the VFI neighbor (U-PE device).

  • vc-id : Virtual circuit identifier.

  • encapsulation mpls : Specifies MPLSas the data encapsulation method.

Specify the N-PE devices that form the layer 2 VPN cross connection with the U-PE

Before you begin

Ensure that the device is in configuration mode.

Procedure

Step 1

Use the interface type number command to specify the interface to configure, and enter interface configuration mode.

Example:

Device(config)# interface GigabitEthernet0/0/0

Step 2

Use the service instance id ethernet command to configure an ethernet service instance on the interface, and enter ethernet service configuration mode.

Example:

Device(config-if)# service instance 10 ethernet

Step 3

Use the encapsulation untagged command define the criteria to map tagged or untagged frame ingress on the interface to the appropriate service instance.

Example:

Device(config-if-srv)# encapsulation untagged

Step 4

Use the exit command to return to interface configuration mode.

Example:

Device(config-if-srv)# exit

Step 5

Use the exit command again to return to global configuration mode.

Example:

Device(config-if)# exit

Step 6

Use the l2vpn xconnect context context-name to create a L2VPN cross connect context, and enter xconnect configuration mode.

Example:

Device(config)# l2vpn xconnect context XC-10

Step 7

Use the member gigabitethernet interface-number [service-instance id] command to specify devices that form a L2VPN cross connect.

Example:

Device(config-xconnect)# member GigabitEthernet0/0/0 service-instance 10

service-instance id : (Optional) Specifies the service instance identifier.

Step 8

Use the member ip-address vc-id encapsulation mpls [group group-name [priority number] command to specify devices that form a L2VPN cross connect.

Example:

Device(config-xconnect)# member 101.101.101.101 10 encapsulation mpls group pwred priority 9

Device(config-xconnect)# member 102.102.102.102 10 encapsulation mpls group pwred priority 10

  • ip-address —IP address of the peer N-PE device.

  • vc-id —Virtual circuit identifier.

  • encapsulation mpls —Specifies Multiprotocol Label Switching (MPLS) as the data encapsulation method.

  • group group-name —Specifies the cross-connect member redundancy group name.

  • priority number —Specifies the cross-connect member priority. The range is from 0 to 16. The highest priority is 0. Lowest priority is 16.

Configuration Example for H-VPLS N-PE Redundancy for MPLS Access

Example of configuring H-VPLS N-PE redundancy for MPLS access

The figure displays a configuration for H-VPLS N-PE redundancy with MPLS access. There is no option to configure multihoming on access VPLS, so the xconnect command with priority is used on uPE1.

Figure 2. H-VPLS N-PE Redundancy with MPLS Access Topology

nPE1 Configuration 


l2vpn vfi context VPLS-10
 vpn id 10
 member 102.102.102.102 encapsulation mpls
 member 103.103.103.103 encapsulation mpls
!
bridge-domain 10
 member vfi VPLS-10
 member 105.105.105.105 10 encapsulation mpls

nPE2 Configuration


l2vpn vfi context VPLS-10
 vpn id 10 
 member 101.101.101.101 encapsulation mpls
 member 103.103.103.103 encapsulation mpls
!
bridge-domain 10
 member vfi VPLS-10
 member 105.105.105.105 10 encapsulation mpls

nPE3 Configuration


l2vpn vfi context VPLS-10
 vpn id 10
 member 101.101.101.101 encapsulation mpls 
 member 102.102.102.102 encapsulation mpls
!
bridge-domain 10
 member vfi VPLS-10

uPE1 Configuration


interface GigabitEthernet0/1/0
 service instance 10 ethernet
 encapsulation dot1q 10
!
l2vpn xconnect context XC-10
 member GigabitEthernet0/1/0 service-instance 10
 member 101.101.101.101 10 encapsulation mpls group pwred priority 9
 member 102.102.102.102 10 encapsulation mpls group pwred priority 10

Verification

Use the show commands to verify that H-VPLS N-PE redundancy for MPLS access is configured successfully.

Sample Output on uPE1 

Device# show xconnect peer 101.101.101.101 vcid 10

Legend:    XC ST=Xconnect State  S1=Segment1 State  S2=Segment2 State
  UP=Up       DN=Down            AD=Admin Down      IA=Inactive
  SB=Standby  HS=Hot Standby     RV=Recovering      NH=No Hardware

XC ST  Segment 1                         S1 Segment 2                         S2
------+---------------------------------+--+---------------------------------+--
UP pri   ac Gi0/1/0:10(Eth VLAN)         UP mpls 101.101.101.101:10           UP

Device# show xconnect peer 102.102.102.102 vcid 10

Legend:    XC ST=Xconnect State  S1=Segment1 State  S2=Segment2 State
  UP=Up       DN=Down            AD=Admin Down      IA=Inactive
  SB=Standby  HS=Hot Standby     RV=Recovering      NH=No Hardware

XC ST  Segment 1                         S1 Segment 2                         S2
------+---------------------------------+--+---------------------------------+--
IA pri   ac Gi0/1/0:10(Eth VLAN)         UP mpls 102.102.102.102:10           SB
Device#

Pseudowire types for H-VPLS

This section describes how the IR1101 router determines Pseudowire (PW) types automatically based on the interface configuration and how to manually override these types to ensure compatibility with far-end devices.

Understanding Pseudowire types

The IR1101 router supports two primary Pseudowire types for H-VPLS:

  • Type 4 (VLAN): Used for Ethernet VLAN interworking.

  • Type 5 (Ethernet): Used for raw Ethernet interworking.

Automatic PW type selection

The router automatically selects the PW type based on the type of interface where the xconnect is configured.

Table 2. Automatic PW type selection

Interface Type

Configuration Method

Default PW Type
Layer 3 Interfaces (Onboard Gig, SP, SPMI, or 4S8I modules) xconnect attached directly to the interface or sub-interface.

Type 5 (Ethernet)

Layer 2 Interfaces (Onboard FastEthernet (Fa) or 4A2T modules)

 xconnect attached to a Switched Virtual Interface (SVI).

Type 4 (VLAN)

Limitations

These are the limitations for selecting Pseudowire types:

  • Compatibility Check: Before configuring H-VPLS, verify the PW type used by the far-end device. If the IR1101 and the remote peer use mismatched types (one using Type 4 and the other Type 5), the connection will fail.

  • SVI Limitation: Configuring an xconnect on an SVI automatically forces the router into Type 4 mode.

  • FastEthernet Support: Onboard FastEthernet (Fa) interfaces are Layer 2 only and require an SVI for H-VPLS configuration.

  • Cisco IOS XE 26.1.1 Cosmetic Issue: In Cisco IOS XE 26.1.1 release, the configuration parser may incorrectly allow you to apply an xconnect directly to a FastEthernet interface. This configuration is not supported and will not function. This issue is resolved in Cisco IOS XE 26.1.1 (or later releases).

  • Always use an SVI for FastEthernet interfaces.

Overriding Pseudowire types

If the far-end device requires a specific PW type that does not match the IR1101 default, you can manually override the setting using an Layer 2 Virtual Private Network (L2VPN) cross-connect profile.

Here is an example of forcing Type 5 on an SVI:

Router(config-pw-class)# encapsulation mpls
Router(config-pw-class)# interworking ethernet
Router(config-pw-class)# exit
Router(config)# interface vlan 100
Router(config-if)# xconnect 10.1.1.1 123 pw-class PW_TYPE_5_PROFILE
Router(config-if)# end

To verify the current PW type use the show l2vpn atom vc [vcid/interface-id]detail command.


Note

You can look for the local interface type or PW type fields in the output to confirm if it is Type 4 or Type 5.