MPLS L2VPN provides point-to-point and point-to-multipoint connections. This chapter describes only the MPLS L2VPN technologies that provide point-to-point connections. For information about the MPLS L2VPN technologies that provide point-to-multipoint connections, see "Configuring VPLS."

About MPLS L2VPN

MPLS L2VPN is an implementation of Pseudo Wire Emulation Edge-to-Edge (PWE3). It offers Layer 2 VPN services over an MPLS or IP backbone. MPLS L2VPN can transparently transmit Layer 2 data for different data link layer protocols such as Ethernet and ATM.

Basic concepts of MPLS L2VPN

CE

A customer edge (CE) is a customer device directly connected to the service provider network.

PE

A provider edge (PE) is a service provider device connected to one or more CEs. It provides VPN access by mapping and forwarding packets between user networks and public tunnels.

AC

An attachment circuit (AC) is a link between a CE and a PE, such as an FR DLCI, ATM VPI/VCI, Ethernet interface, VLAN, or PPP connection.

PW

A Pseudowire (PW) is a virtual bidirectional connection between two PEs. An MPLS PW comprises a pair of LSPs in opposite directions.

Public tunnel

A public tunnel is a connection that carries one or more PWs across the MPLS or IP backbone. It can be an LSP tunnel or a GRE tunnel.

Cross-connect

A cross-connect connects two physical or virtual circuits such as ACs and PWs. It switches packets between the two physical or virtual circuits. Cross-connects include AC to AC cross-connect, AC to PW cross-connect, and PW to PW cross-connect.

Site ID

A site ID uniquely identifies a site in a VPN. Sites in different VPNs can have the same site ID.

RD

A route distinguisher (RD) is added before a site ID to distinguish the sites that have the same site ID but reside in different VPNs. An RD and a site ID uniquely identify a VPN site.

Label block

A label block is a set of labels. It includes the following parameters:

· Label base—The LB specifies the initial label value of the label block. A PE automatically selects an LB value that cannot be manually modified.

· Label range—The LR specifies the number of labels that the label block contains. The LB and LR determine the labels contained in the label block. For example, if the LB is 1000 and the LR is 5, the label block contains labels 1000 through 1004.

· Label-block offset—The LO specifies the offset of a label block. If the existing label block becomes insufficient as the VPN sites increase, you can add a new label block to enlarge the label range. A PE uses an LO to identify the position of the new label block. The LO value of a label block is the sum of the LRs of all previously assigned label blocks. For example, if the LR and LO of the first label block are 10 and 0, the LO of the second label block is 10. If the LR of the second label block is 20, the LO of the third label block is 30.

A label block with LB, LO, and LR as 1000, 10, and 5, respectively, is represented as 1000/10/5.

For example, a VPN has 10 sites, and a PE assigns the first label block LB1/0/10 to the VPN. When another 15 sites are added, the PE keeps the first label block and assigns the second label block LB2/10/15 to extend the network. LB1 and LB2 are the initial label values that are randomly selected by the PE.

Route target

PEs use the BGP route target attribute (also called VPN target attribute) to manage BGP L2VPN information advertisement. PEs support the following types of route target attributes:

· Export target attribute—When a PE sends L2VPN information to the peer PE in a BGP update message, it sets the route target attribute in the update message to an export target. L2VPN information includes the site ID, RD, and label block.

· Import target attribute—When a PE receives an update message from the peer PE, it checks the route target attribute in the update message. If the route target value matches an import target, the PE accepts the L2VPN information in the update message.

Route target attributes determine from which PEs a PE can receive L2VPN information.

MPLS L2VPN network models

MPLS L2VPN network models include the remote connection and local connection models.

As shown in Figure 1, the remote connection model connects two CEs through a PW on an MPLS or IP backbone.

Figure 1 Remote connection model

‌

As shown in Figure 2, the local connection model connects two CEs to the same PE so the CEs can communicate through the PE.

Figure 2 Local connection model

‌

Remote connection establishment

To set up a remote MPLS L2VPN connection:

1. Set up a public tunnel to carry one or more PWs between PEs.

2. Set up a PW to connect customer networks.

3. Set up an AC between a PE and a CE.

4. Bind the AC to the PW.

After the PE receives packets from the AC, it adds the PW label into the packets and sends the packets to the peer PE through the public tunnel.

After the peer PE receives the packets from the public tunnel, it removes the PW label of the packets and forwards the packets to the AC bound to the PW.

Setting up a public tunnel

The public tunnel can be an LSP or GRE tunnel.

If multiple public tunnels exist between two PEs, you can configure a tunnel policy to control tunnel selection. For more information about tunnel policies, see "Configuring tunnel policies."

If a PW is established over an LSP, packets on the PW have two labels. The outer label is the public LSP label that MPLS uses to forward the packet to the peer PE. The inner label is the PW label that the peer PE uses to forward the packet to the destination CE.

Setting up a PW

PWs include static PWs, LDP PWs, BGP PWs, and Circuit Cross Connect (CCC) PWs.

· Static PW establishment

To establish a static PW, configure the peer PE address, and the incoming and outgoing PW labels for the PW on the two PEs. Static PWs consume a small amount of resources but have complex configurations.

· LDP PW establishment

To establish an LDP PW, configure LDP and specify the peer PE address on the two PEs. LDP defines a new FEC type named PW ID FEC for PEs to exchange PW-label bindings. The new FEC type uses a PW ID and a PW data encapsulation type to identify a PW. The PW ID is the ID of the PW between PEs. The PW data encapsulation type specifies the encapsulation type for data transmitted over the PW, such as ATM, FR, Ethernet, or VLAN. PEs advertise the PW label and PW ID FEC in label mapping messages to create a PW. Dynamic PWs have simple configurations but consume more resources than static PWs.

· BGP PW establishment

To establish BGP PWs, BGP advertises label block information in an extended BGP update to PEs in the same VPN. Each PE uses the received label block information to calculate outgoing labels and uses its own label block to calculate incoming labels. After two PEs complete label calculation, a BGP PW is established between them.

BGP PWs have the following features:

¡ Simplified configuration—There is no need to manually specify peer PEs. A PE automatically find peer PEs after receiving label block information from the peer PEs.

¡ Reduced workload—Label block advertisement enables assigning labels for multiple PWs at one time.

· CCC PW establishment

To establish a CCC PW, manually specify the incoming and outgoing labels for the PW on the PEs, and create two static LSPs in opposite directions on P devices between PEs. There is no need to configure a public tunnel for the CCC PW. CCC employs only one level of label to transfer packets. The static LSPs on the P devices transfer data only for the CCC PW. They cannot be used by other connections or MPLS L3VPN.

Setting up an AC

Set up an AC by configuring a link layer connection between a PE and a CE.

An AC is an Ethernet service instance on a Layer 2 Ethernet interface or Layer 2 aggregate interface. It forwards packets that are received on the interface and meet the match criteria of the Ethernet service instance to the bound PW. If the match criterion is VLAN ID, the VLAN is unique on a per interface basis rather than on a global basis.

NOTE:

When VLANs are globally unique, packets with the same VLAN ID are forwarded over the PW bound with that VLAN ID regardless of the receiving interfaces. If VLANs are unique on a per interface basis, packets with the same VLAN ID from different interfaces can be forwarded over different PWs.

‌

Binding the AC to the PW

Bind the Layer 3 physical interface, Layer 3 subinterface, or Ethernet service instance to the PW, so the PE forwards packets between the AC and the PW.

Local connection establishment

To set up a local MPLS L2VPN connection between two CEs:

1. Set up ACs:

Configure the link layer protocol to set up an AC between the PE and each CE. For more information, see "Setting up an AC."

2. Bind the two ACs:

Bind the PE's interfaces connected to the two CEs so the PE can forward packets between CEs.

TDM-CEM

Time Division Multiplexing Circuit Emulation (TDM-CEM) encapsulates TDM bit-streams as PWs over a Packet Switched Network (PSN).

PWE3 TDM-CEM has the following modes:

· Structure Agnostic TDM over Packet (SAToP)—Considers all TDM data as pure bit streams, and fragments and encapsulates the bit streams into packets. SAToP does not interpret TDM data or participate in the TDM signaling.

· Circuit Emulation Service over PSN (CESoPSN)—Identifies and processes the TDM frame format and signaling, and encapsulates the structured TDM data as packets.

TDM has the stringent clock requirements to deliver real-time synchronization services. PSN does not have the stringent clock requirements. To transport TDM services through PSN, use one of the following clock recovery modes on an egress PE to implement clock recovery:

· Adaptive Clock Recovery (ACR)—Based on packet arrival rate and jitter buffer fill level. ACR is used when the ingress and egress PEs do not have a common clock source.

· Differential Clock Recovery (DCR)—Based on time stamps received in RTP header. DCR is used when the ingress and egress PEs have a common clock source.

PW data encapsulation types

MPLS L2VPN transports Layer 2 data of different data link layer protocols through PWs. A PE encapsulates a Layer 2 packet received from an AC according to the PW data encapsulation type.

Relationship between AC types and PW data encapsulation types

The PW data encapsulation type is determined by the link type of the AC.

Table 1 Relationship between AC types and PW data encapsulation types

AC type	PW data encapsulation type
Ethernet	Ethernet
Ethernet	VLAN

‌

Ethernet over MPLS

Ethernet over MPLS uses MPLS L2VPN to connect Ethernets, and delivers Ethernet packets through a PW over the MPLS backbone.

The following PW data encapsulation types are available for Ethernet over MPLS:

· Ethernet—P-tag is not transferred on a PW.

¡ For a packet from a CE:

- If the packet contains a P-tag, the PE removes the P-tag, and adds a PW label and an outer tag into the packet before forwarding it.

- If the packet contains no P-tag, the PE directly adds a PW label and an outer tag into the packet before forwarding it.

¡ For a packet to a CE:

- If the access mode is configured as VLAN by using the ac interface command, the PE adds a P-tag into the packet before sending it to the CE.

- If the access mode is configured as Ethernet by using the ac interface command, the PE directly sends the packet to the CE.

You cannot rewrite or remove existing tags.

· VLAN—Packets transmitted over a PW must carry a P-tag.

¡ For a packet from a CE:

- If the peer PE does not require the ingress to rewrite the P-tag, the PE keeps the P-tag unchanged for the packet, and then encapsulates the packet. If the packet contains no P-tag, the PE adds a null label (the label value is 0) into the packet, and then encapsulates the packet.

- If the peer PE requires the ingress to rewrite the P-tag, the PE changes the P-tag to the expected VLAN tag (the tag value might be 0), and then adds a PW label and an outer tag into the packet. If the packet contains no P-tag, the PE adds a VLAN tag expected by the peer PE (the tag value might be 0), and then adds a PW label and an outer tag into the packet.

¡ For a packet to a CE:

- If the access mode is configured as VLAN by using the ac interface command, the PE rewrites or retains the P-tag before forwarding the packet.

- If the access mode is configured as Ethernet by using the ac interface command, the PE removes the P-tag before forwarding the packet.

Ethernet over MPLS supports the following modes:

· Port mode—A Layer 3 Ethernet interface is bound to a PW. Packets received from the Layer 3 Ethernet interface are forwarded through the bound PW. The default PW data encapsulation type for port mode is Ethernet.

Figure 3 Packet encapsulation in port mode

‌

· VLAN mode—A Layer 3 Ethernet subinterface is bound to a PW. Packets received from the VLAN are forwarded through the bound PW. The peer PE can modify the VLAN tag as needed. The default PW data encapsulation type for VLAN mode is VLAN.

· Flexible mode—An Ethernet service instance on a Layer 2 Ethernet interface or Layer 2 aggregate interface is bound to a PW. Packets that are received from the interface and meet the match criteria of the Ethernet service instance are forwarded through the bound PW. You can configure flexible match criteria for the Ethernet service instance. For example, configure the Ethernet service instance to match all packets, tagged packets, or untagged packets. The default PW data encapsulation type for flexible mode is VLAN. Flexible mode can also implement the port and VLAN modes through match criteria configuration.

PPP/HDLC over MPLS

PPP/HDLC over MPLS uses MPLS L2VPN to connect PPPs or HDLC networks, and delivers PPP or HDLC packets through a PW over the MPLS backbone.

If the link type of the AC is PPP, the PW data encapsulation type is PPP. If the link type of the AC is HDLC, the PW data encapsulation type is HDLC.

PPP/HDLC over MPLS supports only the port mode. You can associate a Layer 3 interface whose encapsulation type is PPP or HDLC with a PW.

In a PPP/HDLC over MPLS network, a PE processes a PPP or HDLC packet as follows:

1. After receiving a packet from a Layer 3 interface, the PE searches for the PW bound to the interface.

2. The PE encapsulates the packet and sends the packet to the peer PE through the PW.

3. The peer PE removes the outer encapsulation to get the original PPP or HDLC packet, and then forwards the packet to the user network.

TDM-CEM

TDM-CEM uses MPLS L2VPN to deliver TDM packets through a PW over the MPLS backbone. If the link type of the AC is E1 or T1, the following PW data encapsulation types are available:

· SAToP—Provides unstructured, transparent TDM transport of E1 or T1 frames through a PW over the MPLS backbone. All time slots on an E1 or T1 interface are forwarded through the same PW. SAToP includes structure-agnostic E1 over packet and structure-agnostic T1 (DS1) over packet.

After you create an unstructured CEM interface and bind it to a PW, all bit streams received from the interface are forwarded through the PW.

· CESoPSN basic mode—Provides structured TDM transport of E1 or T1 frames through a PW.

After you create a structured CEM interface and bind it to a PW, the bit streams of the specified time slots received from the interface are forwarded through the PW.

Control word

The control word field is between the MPLS label stack and the Layer 2 data. It carries control information for the Layer 2 frame, for example, the sequence number.

The control word feature has the following functions:

· Avoids fragment disorder. In multipath forwarding, fragments received might be disordered. The control word feature reorders the fragments according to the sequence number carried in the control word field.

· Transfers specific Layer 2 frame flags, such as the FECN bit and BECN bit of Frame Relay.

· Identifies the original payload length for packets that include padding.

When the PW data encapsulation type is FR DLCI or ATM AAL5 SDU VCC, packets on the PW always carry the control word field, and the control word feature cannot be disabled.

When the PW data encapsulation type is Ethernet or VLAN, the control word field is optional. You can configure whether to carry the control word field in packets sent on the PW. If you enable the control word feature on both PEs, packets transmitted on the PW carry the control word field. Otherwise, the packets do not carry the control word field.

MPLS L2VPN interworking

CEs might connect to PEs through various types of links, such as ATM, FR, HDLC, Ethernet, and PPP. MPLS L2VPN interworking connects such CEs and allow them to communicate.

MPLS L2VPN supports Ethernet interworking and IP interworking modes. The device only supports IP interworking. Only local MPLS L2VPN connections, static PWs, LDP PWs, and remote CCC connections support the interworking feature.

Figure 4 Ethernet to PPP interworking

‌

As shown in Figure 4, a packet in an MPLS L2VPN interworking scenario is forwarded as follows:

2. CE 1 sends an Ethernet frame destined for CE 2 to PE 1.

3. PE 1 checks whether the packet encapsulated in the received Ethernet frame is an IP packet.

¡ If yes, PE 1 removes the Ethernet header, adds PW label V and tunnel label T to the IP packet, and forwards the packet to PE 2 through the tunnel.

¡ If not, PE 1 drops the frame.

4. PE 2 obtains the output interface according to the PW label V in the received packet, removes the PW label, adds an PPP header, and forwards the PPP frame through the output interface to CE 2.

In an MPLS L2VPN interworking scenario, link layer negotiation packets cannot be delivered on the backbone network. Therefore, Layer 2 connections cannot be established between CEs. CEs must establish Layer 2 connections with the PEs. For example, CE 2 and PE 2 must perform PPP negotiation to establish a PPP connection.

Bypass PW

To resolve the problem, you can create a single bypass PW or double bypass PWs between PE 2 and PE 3.

Single bypass PW

As shown in Figure 5, after you create a single bypass PW between PE 2 and PE 3, the bypass PW provides both PW bypass and AC bypass. Traffic is forwarded as follows:

· When the AC between PE 2 and CE 2 fails, traffic from CE 1 to CE 2 goes through the path CE 1—PE 1—PE 2—PE 3—CE 2.

· When the primary PW fails, traffic from CE 2 to CE 1 goes through the path CE 2—PE 2—PE 3—PE 1—CE 1.

In a single bypass PW network, traffic is switched to the bypass PW instead of the backup PW when the AC or primary PW fails.

Figure 5 Single bypass PW

‌

Double bypass PWs

Double bypass PWs refer to an AC-bypass PW used to forward traffic when the AC fails and a PW-bypass PW used to forward traffic when the primary PW fails. Compared with single bypass PWs, double bypass PWs reduce the traffic switchover time and provide higher reliability.

As shown in Figure 6, after you create double bypass PWs between PE 2 and PE 3, traffic is forwarded as follows:

· When the AC between PE 2 and CE 2 fails, traffic from CE 1 to CE 2 goes through the path CE 1—PE 1—PE 2—PE 3—CE 2. The traffic is forwarded from PE 2 to PE 3 through the AC-bypass PW. After the primary/backup PW switchover completes, the traffic is switched to the backup PW, so the final traffic forwarding path is CE 1—PE 1—PE 3—CE 2.

· When the primary PW fails, traffic from CE 2 to CE 1 goes through the path CE 2—PE 2—PE 3—PE 1—CE 1. The traffic is forwarded from PE 2 to PE 3 through the PW-bypass PW. . After the primary/backup PW switchover completes, the traffic is switched to the backup PW, so the final traffic forwarding path is CE 2—PE 3—PE 1—CE 1.

Figure 6 Double bypass PWs

‌

MPLS L2VPN diagnostic troubleshooting

This feature identifies whether the MPLS L2VPN module functions correctly, for exampel, whether PWs have been established successfully and whether PW flapping has occurred to help you locate MPLS L2VPN exceptions. For more information about MPLS L2VPN diagnostic troubleshooting, see diagnostic troubleshooting configuration in Network Management and Monitoring Configuration Guide.

MPLS L2VPN tasks at a glance

Configuring a remote connection

1. Enabling L2VPN

2. Configuring an AC

Configuring an Ethernet service instance on an interface

3. Configuring a cross-connect

4. Configuring a PW

Configure a static PW, LDP PW, BGP PW, and remote CCC connection as needed.

¡ (Optional.) Configuring a PW class

¡ Configuring a static PW

¡ Configuring an LDP PW

¡ Configuring a BGP PW

¡ Configuring a remote CCC connection

5. Binding an AC to a cross-connect

6. (Optional.) Maintaining an MPLS L2VPN network

Enabling SNMP notifications for L2VPN PW

Configuring a local connection

1. Enabling L2VPN

2. Configuring an AC

To create a local connection, you must configure two ACs.

Configuring an Ethernet service instance on an interface

3. Configuring a cross-connect

4. Binding an AC to a cross-connect

Perform this task to bind the two ACs to the same cross-connect.

Prerequisites for MPLS L2VPN

To establish an MPLS L2VPN, you must perform the following tasks:

1. Configure an IGP to achieve IP connectivity within the backbone.

2. Configure basic MPLS, or LDP to set up public tunnels across the backbone.

Enabling L2VPN

Prerequisites

Before you enable L2VPN, perform the following tasks:

· Configure an LSR ID for the PE with the mpls lsr-id command.

· Enable MPLS with the mpls enable command on the core-facing interface of the PE.

For more information about the mpls lsr-id and mpls enable commands, see MPLS Command Reference.

Procedure

1. Enter system view.

system-view

2. Enable L2VPN.

l2vpn enable

By default, L2VPN is disabled.

Configuring an Ethernet service instance on an interface

About this task

When the PE is connected to a CE through a Layer 2 Ethernet interface or Layer 2 aggregate interface, you can configure an Ethernet service instance on the interface to match packets for the AC.

Restrictions and guidelines

For information about configuring the match criterion of an Ethernet service instance by using the encapsulation command, see MPLS L2VPN commands in MPLS Command Reference.

Procedure

1. Enter system view.

system-view

2. Enter interface view.

¡ Enter Layer 2 Ethernet interface view.

interface interface-type interface-number

¡ Enter Layer 2 aggregate interface view.

interface bridge-aggregation interface-number

3. Create an Ethernet service instance and enter Ethernet service instance view.

service-instance instance-id

4. Configure a packet match criterion for the Ethernet service instance.

¡ Match packets with the specified inner VLAN IDs.

encapsulation c-vid { vlan-id | vlan-id-list }

¡ Match packets with the specified outer VLAN IDs.

encapsulation s-vid { vlan-id | vlan-id-list } [ only-tagged ]

¡ Match packets with the specified outer VLAN IDs and the specified inner VLAN IDs.

encapsulation s-vid vlan-id c-vid { vlan-id-list | all }

¡ Match packets that do not have a VLAN tag.

encapsulation untagged

By default, no packet match criterion is configured.

Configuring a cross-connect

1. Enter system view.

system-view

2. Create a cross-connect group and enter cross-connect group view.

xconnect-group group-name

3. (Optional.) Configure a description for the cross-connect group.

description text

By default, no description is configured for a cross-connect group.

4. (Optional.) Enable the cross-connect group.

undo shutdown

By default, the cross-connect group is enabled.

5. Create a cross-connect and enter cross-connect view.

connection connection-name

6. (Optional.) Set an MTU for the PW.

mtu size

The default MTU is 1500 bytes.

The two PEs on an LDP PW must have the same MTU configured for the PW. Otherwise, the PW cannot come up.

Configuring a PW

Configuring a PW class

About this task

You can configure PW attributes such as the PW data encapsulation type and enable control word in a PW class. PWs with the same attributes can use the same PW class.

Procedure

1. Enter system view.

system-view

2. Create a PW class and enter PW class view.

pw-class class-name

By default, no PW classes exist.

3. Enable control word.

control-word enable

By default, control word is disabled.

4. Specify the PW data encapsulation type.

pw-type { ethernet | vlan }

By default, the PW data encapsulation type is VLAN.

Configuring a static PW

1. Enter system view.

system-view

2. Enter cross-connect group view.

xconnect-group group-name

3. Enter cross-connect view.

connection connection-name

4. Configure a static PW, and enter cross-connect PW view.

peer ip-address pw-id pw-id in-label label-value out-label label-value [ pw-class class-name | tunnel-policy tunnel-policy-name ] *

Configuring an LDP PW

About this task

After an LDP PW is created, the PE automatically sends a targeted hello to create an LDP session to the peer PE. Then, the PE exchanges the PW ID FEC and PW label mapping with the peer.

Prerequisites

Before you configure an LDP PW, enable global and interface MPLS LDP on the PE. For information about MPLS LDP configuration, see "Configuring LDP."

Procedure

1. Enter system view.

system-view

2. Enter cross-connect group view.

xconnect-group group-name

3. Enter cross-connect view.

connection connection-name

4. Configure an LDP PW, and enter cross-connect PW view.

peer ip-address pw-id pw-id [ pw-class class-name | tunnel-policy tunnel-policy-name ] *

Configuring a BGP PW

Configuring BGP to advertise MPLS L2VPN label block information

1. Enter system view.

system-view

2. Enable BGP instance and enter BGP instance view.

bgp as-number [ instance instance-name ]

By default, BGP is disabled.

3. Configure the remote PE as a BGP peer.

peer { group-name | ip-address [ mask-length ] } as-number as-number

For more information about this command, see Layer 3—IP Routing Command Reference.

4. Create the BGP L2VPN address family and enter BGP L2VPN address family view.

address-family l2vpn

5. Enable BGP to exchange BGP L2VPN information with the specified peer or peer group.

peer { group-name | ip-address [ mask-length ] } enable

By default, BGP cannot exchange BGP L2VPN information with any peer or peer group.

For more information about this command, see Layer 3—IP Routing Command Reference.

6. Enable BGP to exchange label block information with the specified peer or peer group.

peer { group-name | ip-address [ mask-length ] } signaling [ non-standard ]

By default, BGP can exchange label block information with a BGP L2VPN peer or peer group by using RFC 4761 MP_REACH_NLRI.

7. Configure the BGP L2VPN address family.

For more information, see "Configuring BGP L2VPN address family."

8. Reset BGP L2VPN sessions.

For more information, see "Resetting BGP sessions of L2VPN address family."

Creating a BGP PW

1. Enter system view.

system-view

2. Enter cross-connect group view.

xconnect-group group-name

3. Configure the cross-connect group to automatically discover neighbors and create PWs through BGP and enter auto-discovery cross-connect group view.

auto-discovery bgp

By default, a cross-connect group does not automatically discover neighbors or create PWs through BGP.

4. Configure an RD for the cross-connect group.

route-distinguisher route-distinguisher

By default, no RD is configured for the cross-connect group.

5. Configure route targets for the cross-connect group.

vpn-target vpn-target&<1-8> [ both | export-extcommunity | import-extcommunity ]

By default, no route targets are configured for the cross-connect group.

6. (Optional.) Specify a PW class for the auto-discovery cross-connect group.

pw-class class-name

By default, no PW class is specified.

7. (Optional.) Set an MTU for the PW.

mtu size

The default MTU is 1500 bytes.

8. Create a local site and enter site view.

site site-id [ range range-value ] [ default-offset default-offset ]

9. Create a cross-connect and enter auto-discovery cross-connect view.

connection remote-site-id remote-site-id

After you execute this command, a PW to the specified remote site is created and is bound to the cross-connect.

10. (Optional.) Specify a tunnel policy for the auto-discovery cross-connect.

tunnel-policy tunnel-policy-name

By default, no tunnel policy is specified.

Configuring BGP L2VPN address family

1. Enter system view.

system-view

2. Enter BGP instance view.

bgp as-number [ instance instance-name ]

3. Enter BGP L2VPN address family view.

address-family l2vpn

4. Permit the local AS number to appear in routes from the specified peer or peer group and specify the appearance times.

peer { group-name | ip-address [ mask-length ] } allow-as-loop [ number ]

By default, the local AS number is not allowed in routes from a peer or peer group.

For more information about this command, see Layer 3—IP Routing Command Reference.

5. Enable route target-based filtering of incoming BGP L2VPN information.

policy vpn-target

By default, route target-based filtering of incoming BGP L2VPN information is enabled.

6. Configure BGP route reflection:

a. Configure the router as a route reflector and specify a peer or peer group as its client.

peer { group-name | ip-address [ mask-length ] } reflect-client

By default, no route reflector or client is configured.

b. Enable L2VPN information reflection between clients.

reflect between-clients

By default, L2VPN information reflection between clients is enabled.

c. Configure the cluster ID of the route reflector.

reflector cluster-id { cluster-id | ip-address }

By default, a route reflector uses its own router ID as the cluster ID.

d. Configure a filtering policy for reflected L2VPN information.

rr-filter ext-comm-list-number

By default, the route reflector does not filter reflected L2VPN information.

For more information about the commands, see Layer 3—IP Routing Command Reference.

7. Configure optimal route selection delay.

¡ Set the optimal route selection delay timer for an address family.

route-select delay delay-value

¡ Enable optimal route selection delay based on DOWN-to-UP peer state changes and set a delay timer.

route-select suppress on-peer-up milliseconds

By default, optimal route selection is not delayed.

For more information about this command, see BGP commands in Layer 3—IP Routing Command Reference.

Resetting BGP sessions of L2VPN address family

To reset BGP sessions of the L2VPN address family, execute one of the following command in user view:

· Perform manual soft-reset for BGP sessions of the L2VPN address family.

refresh bgp [ instance instance-name ] { ip-address [ mask-length ] | all | external | group group-name | internal } { export | import } l2vpn

· Reset BGP sessions of the L2VPN address family.

reset bgp [ instance instance-name ] { as-number | ip-address [ mask-length ] | all | external | group group-name | internal } l2vpn

For more information about the commands, see Layer 3—IP Routing Command Reference.

Configuring a remote CCC connection

Restrictions and guidelines

The outgoing label specified on a device must be the same as the incoming label specified on the next-hop device.

CCC connection settings such as the encapsulation type and control word feature must be consistent on the two PEs. Otherwise, the PEs might fail to forward packets over the CCC connection.

Procedure

1. Configure the PE devices of the CCC connection:

a. Enter system view.

system-view

b. Enter cross-connect group view.

xconnect-group group-name

c. Enter cross-connect view.

connection connection-name

d. Create a remote CCC connection.

ccc in-label in-label-value out-label out-label-value { nexthop nexthop | out-interface interface-type interface-number } [ pw-class class-name ]

Use the out-interface keyword to specify the outgoing interface only on a point-to-point link. On other types of interfaces such as Layer 3 Ethernet interfaces and VLAN interfaces, you must use the nexthop keyword to specify the IP address of the next hop.

2. Configure P devices of the CCC connection:

a. Enter system view.

system-view

b. Configure a static LSP for each direction of the CCC connection.

static-lsp transit lsp-name in-label in-label { nexthop next-hop-ip-address | outgoing-interface interface-type interface-number } out-label out-label

For more information about this command, see MPLS Command Reference.

Binding an AC to a cross-connect

About binding an AC to a cross-connect

On a Layer 2 Ethernet or Layer 2 aggregate interface, you can create an Ethernet service instance and bind it to a cross-connect. The Ethernet service instance matches packets received on that interface. The matching packets are then forwarded to the bound PW or another AC. An Ethernet service instance can match all packets, tagged packets, or untagged packets.

When you bind an AC to a cross-connect, you can associate Track with the AC. Then, the AC is up only when one or more of the associated track entries are positive.

Restrictions and guidelines for binding an AC to a cross-connect

If a Layer 2 Ethernet interface has been added to a link aggregation group, you cannot bind an Ethernet service instance on the interface to a cross-connect, and vice versa.

Binding an Ethernet service instance to a non-BGP cross-connect

1. Enter system view.

system-view

2. Enter cross-connect group view.

xconnect-group group-name

3. Enter cross-connect view.

connection connection-name

4. Bind the Ethernet service instance on the interface to the cross-connect and enter cross-connect AC view.

ac interface interface-type interface-number[ track track-entry-number&<1-3> ]

By default, no Ethernet service instance is bound to the cross-connect.

Binding an Ethernet service instance to a BGP cross-connect

1. Enter system view.

system-view

2. Enter cross-connect group view.

xconnect-group group-name

3. Enter auto-discovery cross-connect group view.

auto-discovery bgp

4. Enter site view.

site site-id [ range range-value ] [ default-offset default-offset-value ]

5. Enter auto-discovery cross-connect view.

connection remote-site-id remote-site-id

6. Bind the Ethernet service instance on the interface to the BGP cross-connect.

ac interface interface-type interface-number[ track track-entry-number&<1-3> ]

By default, no Ethernet service instance is bound to the BGP cross-connect.

Enabling SNMP notifications for L2VPN PW

About this task

This feature enables L2VPN to generate SNMP notifications when the device does not support L2VPN flow labels, or PW deletions, CCC up and down, PW switchovers, or PW status changes occur. For L2VPN event notifications to be sent correctly, you must also configure SNMP on the device. For more information about SNMP configuration, see the network management and monitoring configuration guide for the device.

Procedure

1. Enter system view.

system-view

2. Enable SNMP notifications for L2VPN PW.

snmp-agent trap enable l2vpn [ ccc-up-down | flow-label-nonsupport | pw-delete | pw-switch | pw-up-down ] *

By default, SNMP notifications for L2VPN PW are disabled.

Display and maintenance commands for MPLS L2VPN

Execute display commands in any view and reset commands in user view.

Task	Command
Display BGP L2VPN peer group information.	display bgp [ instance instance-name ] group l2vpn [ group-name group-name ]
Display L2VPN label block information discovered by BGP.	display bgp [ instance instance-name ] l2vpn signaling [ peer ip-address { advertised \| received } \| route-distinguisher route-distinguisher [ site-id site-id [ label-offset label-offset [ advertise-info ] ] ] ]
Display BGP L2VPN peer information.	display bgp [ instance instance-name ] peer l2vpn [ ip-address mask-length \| group-name group-name log-info \| ip-address { log-info \| verbose } \| verbose ]
Display BGP L2VPN update group information.	display bgp [ instance instance-name ] update-group l2vpn [ ip-address ]
Display L2VPN label block information.	display l2vpn bgp [ peer ip-address \| local ] [ xconnect-group group-name ] [ verbose ]
Display cross-connect forwarding information.	display l2vpn forwarding { ac \| pw } [ xconnect-group group-name ] [ slot slot-number ] [ verbose ]
Display LDP PW label information.	display l2vpn ldp [ peer ip-address [ pw-id pw-id ] \| xconnect-group group-name ] [ verbose ]
Display L2VPN PW information.	display l2vpn pw [ xconnect-group group-name ] [ protocol { bgp \| ldp \| static } ] [ verbose ]
Display L2VPN PW state machine information.	display l2vpn pw state-machine [ vsi vsi-name \| xconnect-group group-name ]
Display PW class information.	display l2vpn pw-class [ class-name ]
Display Ethernet service instance information.	display l2vpn service-instance [ interface interface-type interface-number [ service-instance instance-id ] ] [ verbose ]
Display cross-connect group information.	display l2vpn xconnect-group [ name group-name ] [ verbose ]
Reset BGP sessions for L2VPN.	reset bgp [ instance instance-name ] { as-number \| ip-address [ mask-length ] \| all \| external \| group group-name \| internal } l2vpn

‌

For more information about the display bgp group l2vpn, display bgp peer l2vpn, display bgp update-group l2vpn, and reset bgp l2vpn commands, see Layer 3—IP Routing Command Reference.

07-MPLS Configuration Guide

MPLS L2VPN interworking

Single bypass PW

Double bypass PWs

MPLS L2VPN diagnostic troubleshooting

Prerequisites

Procedure

Configuring an Ethernet service instance on an interface

About this task

Restrictions and guidelines

Procedure

Configuring a cross-connect

Configuring a PW class

About this task

Procedure

About this task

Prerequisites

Procedure

Configuring BGP L2VPN address family

Resetting BGP sessions of L2VPN address family

Configuring a remote CCC connection

Restrictions and guidelines

Procedure

About this task

Procedure

Intelligent Terminal Products

Product Support Services

Technical Service Solutions

Resource Center

Policy

Online Help

Become a Partner

Partner Policy & Program

Global Learning

Partner Sales Resources

Service Business

News & Events

Contact Us