Cisco 10000 Series Router Software Configuration Guide - Configuring L2VPN Interworking [Cisco 10000 Series Routers]

Table Of Contents

Configuring L2VPN Interworking

Ethernet to VLAN—Bridged Interworking

Configuring L2VPN Interworking

Verifying the Configuration

Configuration Examples of Ethernet to VLAN—Bridged

Ethernet to VLAN over LS—Bridged: Example

Ethernet to VLAN over AToM—Bridged: Example

Ethernet/VLAN to ATM AAL5 Interworking

Prerequisites of Ethernet/VLAN to ATM AAL5 Interworking

Restrictions of Ethernet/VLAN to ATM AAL5 Interworking

ATM AAL5 to Ethernet Local Switching—Bridged Interworking

ATM AAL5 to VLAN 802.1Q Local Switching—Bridged Interworking

ATM AAL5 to Ethernet Port AToM—Bridged Interworking

ATM AAL5 to Ethernet VLAN 802.1Q AToM—Bridged Interworking

Configuration Tasks and Examples

Local Switching

AToM

Ethernet/VLAN to Frame Relay Interworking

Prerequisites of Ethernet/VLAN to Frame Relay Interworking

Restrictions for Ethernet/VLAN to Frame Relay Interworking

FR DLCI to Ethernet Local Switching—Bridged Interworking

FR DLCI to VLAN 802.1Q Local Switching—Bridged Interworking

FR DLCI to Ethernet Port AToM—Bridged Interworking

FR DLCI to Ethernet VLAN 802.1Q AToM—Bridged Interworking

Configuration Tasks and Examples

Local Switching

AToM

Verifying L2VPN Interworking

Configuring L2VPN Interworking

Interworking is the transforming function required to interconnect two heterogeneous alternating currents (ACs). Several types of interworking functions exist. The function that is used depends on the type of ACs being used, the type of data being carried, and the level of functionality required. The two main interworking functions supported in Cisco IOS software are:

•Bridged Interworking—Used when only Layer 2 (L2) packets are considered without regard to Layer 3 contents. No routing participation by the Internet Service Provider (ISP) exists. In particular, the software supports the use of the Ethernet (port) over MPLS pseudowire for bridged interworking. For this reason, this type of interworking function is also called Ethernet Interworking.

•Routed Interworking—Used to carry Layer 3 packets. A different routed interworking function exists for each protocol type. The most common routed interworking function supports Internet Protocol (IP). Therefore, this type of interworking function is also called IP Interworking, and a new type of pseudowire, IP over MPLS, is used.

Note Cisco 10000 series of routers only support Ethernet interworking.

Layer 2 transport over MPLS and IP already exists for like-to-like attachment circuits, such as Ethernet-to-Ethernet or PPP-to-PPP. L2VPN Interworking builds on this functionality by allowing disparate attachment circuits to be connected. An interworking function facilitates the translation between different Layer 2 encapsulations. Several interworking modes exist, but the Cisco 10000 series router supports only bridged interworking, also known as Ethernet interworking.

To specify a mode, issue the interworking {ethernet | ip} command in pseudowire-class configuration mode. The interworking command causes the attachment circuits to be terminated locally. The ethernet keyword causes Ethernet frames to be extracted from the attachment circuit and sent over the pseudowire. Ethernet end-to-end transmission is assumed. Attachment circuit frames that are not Ethernet are dropped. In the case of VLAN, the VLAN tag is removed, leaving an untagged Ethernet frame.

This chapter describes the following L2VPN like-to-like and interworking features:

•Ethernet to VLAN—Bridged Interworking

•Ethernet/VLAN to ATM AAL5 Interworking

•Ethernet/VLAN to Frame Relay Interworking

•Verifying L2VPN Interworking

Ethernet to VLAN—Bridged Interworking

In Ethernet Interworking, also called as bridged interworking, Ethernet frames are bridged across the pseudowire. The customer edge (CE) routers could be natively bridging Ethernet or could be routing using a bridged encapsulation model, such as Bridge Virtual Interface (BVI) or RBE. The PE routers operate in Ethernet like-to-like mode.

The Ethernet to VLAN (Bridged) feature is described in the following topics:

•Configuring L2VPN Interworking

•Verifying the Configuration

•Configuration Examples of Ethernet to VLAN—Bridged

Configuring L2VPN Interworking

Enabling L2VPN Interworking requires that you add the interworking command to the list of commands that comprise the pseudowire.

SUMMARY STEPS

1. enable

2. configure terminal

3. pseudowire-class name

4. encapsulation mpls

5. interworking ethernet

DETAILED STEPS

Command or Action

Purpose

Step 1

enable
Example:

Router> enable

Enables privileged EXEC mode. if prompted, enter your password.

Step 2

configure terminal
Example:

Router# configure terminal

Enters global configuration mode.

Step 3

pseudowire-class name
Example:

Router(config)# pseudowire-class class1

Establishes a pseudowire class with a name that you specify. Enters pseudowire class configuration mode.

Step 4

encapsulation mpls
Example:

Router(config-pw)# encapsulation mpls

Specifies the tunneling encapsulation.

Step 5

interworking ethernet
Example:

Router(config-pw)# interworking ethernet

Specifies the type of pseudowire and the type of traffic that can flow across it.

Verifying the Configuration

You can verify the AToM configuration by using the show mpls l2transport vc detail command. In the following example, the interworking type appears in bold.
PE1

PE2
Router# show mpls l2transport vc detail
Local interface: Fa1/1/0 up, line protocol up, Ethernet up
Destination address: 10.9.9.9, VC ID: 123, VC status: up
Preferred path: not configured
Default path: active
Tunnel label: 17, next hop 10.1.1.3
Output interface: Fa4/0/0, imposed label stack {17 20}
Create time: 01:43:50, last status change time: 01:43:33
Signaling protocol: LDP, peer 10.9.9.9:0 up
MPLS VC labels: local 16, remote 20
Group ID: local 0, remote 0
MTU: local 1500, remote 1500
Remote interface description:
Sequencing: receive disabled, send disabled
VC statistics:
packet totals: receive 15, send 4184
byte totals: receive 1830, send 309248
packet drops: receive 0, send 0
Router# show mpls l2transport vc detail
Local interface: Fa2/0.3 up, line protocol up, Eth VLAN 10 up
MPLS VC type is Ethernet, interworking type is Ethernet
Destination address: 10.8.8.8, VC ID: 123, VC status: up
Preferred path: not configured
Default path: active
Tunnel label: 16, next hop 10.1.1.3
Output interface: Fa6/0, imposed label stack {16 16}
Create time: 00:00:26, last status change time: 00:00:06
Signaling protocol: LDP, peer 10.8.8.8:0 up
MPLS VC labels: local 20, remote 16
Group ID: local 0, remote 0
MTU: local 1500, remote 1500
Remote interface description:
Sequencing: receive disabled, send disabled
VC statistics:
packet totals: receive 5, send 0
byte totals: receive 340, send 0
packet drops: receive 0, send 0
Configuration Examples of Ethernet to VLAN—Bridged

This section contains examples of Ethernet to VLAN for both local switching (LS) and AToM:

•Ethernet to VLAN over LS—Bridged: Example

•Ethernet to VLAN over AToM—Bridged: Example

Ethernet to VLAN over LS—Bridged: Example
PE
config t
interface atm 2/0/0
	pvc 0/200 l2transport
	encapsulation aal5snap
interface gigabitethernet 5/1/0
	no ip address
connect ETH-VLAN gigabitethernet 5/0/0 gigabitethernet 5/1/0.3 
interworking ethernet
Ethernet to VLAN over AToM—Bridged: Example
PE1

PE2
ip cef
!
mpls label protocol ldp
mpls ldp router-id Loopback0 force
!
pseudowire-class atom
encapsulation mpls
!
interface Loopback0
ip address 10.9.9.9 255.255.255.255
!
interface FastEthernet0/0
no ip address
!
interface FastEthernet1/0
xconnect 10.9.9.9 123 pw-class atom
ip cef
!
mpls label protocol ldp
mpls ldp router-id Loopback0 force
!
pseudowire-class atom-eth-iw
encapsulation mpls
interworking ethernet
!
interface Loopback0
ip address 10.8.8.8 255.255.255.255
!
interface FastEthernet1/0.1
encapsulation dot1q 100
xconnect 10.9.9.9 123 pw-class atom-eth-iw
Ethernet/VLAN to ATM AAL5 Interworking

The Ethernet/VLAN to ATM AAL5 Interworking feature is described in the following topics:

•Prerequisites of Ethernet/VLAN to ATM AAL5 Interworking

•Restrictions of Ethernet/VLAN to ATM AAL5 Interworking

•ATM AAL5 to Ethernet Local Switching—Bridged Interworking

•ATM AAL5 to VLAN 802.1Q Local Switching—Bridged Interworking

•ATM AAL5 to Ethernet Port AToM—Bridged Interworking

•ATM AAL5 to Ethernet VLAN 802.1Q AToM—Bridged Interworking

•Configuration Tasks and Examples

Prerequisites of Ethernet/VLAN to ATM AAL5 Interworking

Before you configure Ethernet/VLAN to ATM AAL5 Interworking on a network, you must enable Cisco Express Forwarding.

Restrictions of Ethernet/VLAN to ATM AAL5 Interworking

In Cisco IOS Release 12.2(33)SB, the Ethernet/VLAN to ATM AAL5 local switching has the following restrictions:

•The following translations are only supported and other translations are dropped:

–Ethernet without LAN FCS (AAAA030080C200070000)

–Spanning tree (AAAA030080C2000E)

•ATM encapsulation types supported for bridged interworking: aal5snap.

•The existing QoS functionality for ATM is supported, including setting the ATM CLP bit.

•Only ATM AAL5 virtual circuit (VC) mode is supported. ATM VP and port mode are not supported.

•The non-AAL5 traffic is punted, for example, OAM cells. The end-to-end F5 loopback cells are looped back onto the PE router.

•If the Ethernet frame arriving from Ethernet CE includes a 802.1Q header (VLAN header), due to the type of endpoint attachment (Ethernet port mode), the VLAN header stays in the frame and it is forwarded to the ATM CE, as shown in Figure 18-1.

Figure 18-1 Protocol Stack for ATM AAL5 to Ethernet Local Switching Bridged Interworking—With VLAN Header

In Cisco IOS Release 12.2(33)SB, the Ethernet/VLAN to ATM AAL5 AToM has the following restrictions:

•The following translations are only supported and other translations are dropped:

–Ethernet without LAN FCS (AAAA030080C200070000)

–Spanning tree (AAAA030080C2000E)

•ATM encapsulation types supported for bridged interworking: aal5snap.

•The existing QoS functionality for ATM is supported, including setting the ATM CLP bit.

•Only ATM AAL5 VC mode is supported. ATM VP and port mode are not supported.

•SVCs are not supported.

•Individual AAL5 ATM cells are assembled into frames before being sent across the pseudowire.

•Non-AAL5 traffic, (such as OAM cells) is punted to be processed at RP level. A VC that has been configured with OAM cell emulation on the ATM PE router (using the oam-ac emulation-enable CLI command) can send end-to-end F5 loopback cells at configured intervals toward the CE router.

•When the pseudowire is down, an F5 end-to-end segment AIS/RDI (Alarm indication signal/Remote defect indication) is sent from the PE router to the CE router.

•If the Ethernet frame arriving from Ethernet CE includes a 802.1Q header (VLAN header), due to the type of endpoint attachment (Ethernet port mode), the VLAN header stays in the frame across the pseudowire (Figure 18-2).

Figure 18-2 Protocol Stack for ATM to Ethernet AToM Bridged Interworking—With VLAN Header

ATM AAL5 to Ethernet Local Switching—Bridged Interworking

This interworking type provides interoperability between Ethernet attachment VC and ATM attachment VC connected to the same PE router. For this interworking type, Bridged encapsulation is used, corresponding to the Bridged Interworking mechanism.

•In Ethernet to ATM direction, the PE router forwards the Layer 2 packet without any change to the egress interface, encapsulating the Layer 2 packet over AAL5 using Bridged encapsulation.

•In ATM to Ethernet direction, the ATM header and bridged encapsulation get discarded and the Layer 2 packet is sent out with Ethernet encapsulation.

Figure 18-3 shows the protocol stack for ATM to Ethernet local switching -bridged interworking. The ATM side has an encapsulation type as aal5snap.

Figure 18-3 Protocol Stack for ATM AAL5 to Ethernet Local Switching Bridged Interworking

ATM AAL5 to VLAN 802.1Q Local Switching—Bridged Interworking

This interworking type provides interoperability between ATM attachment VC and Ethernet VLAN attachment VC connected to the same PE router. As in the ATM to Ethernet case, Bridged encapsulation is used, corresponding to Bridged (Ethernet) Interworking mechanism.

In case of Ethernet VLAN attachment, the VLAN ID is a service delimiter, so the VLAN header is not included in the frame to and from the ATM CE.

•In the VLAN to ATM direction, the PE router discards the VLAN header from the Layer 2 packet. The PE router sends the frame to the ATM egress interface after encapsulating the L2 packet over AAL5 using Bridged encapsulation.

•In the ATM to VLAN direction, the ATM header and bridged encapsulation are discarded and the L2 packet is sent out with a VLAN header inserted following the destination/source MAC addresses.

The protocol stack for ATM to VLAN local switching is shown in Figure 18-3. The ATM side has an encapsulation type of aal5snap.

ATM AAL5 to Ethernet Port AToM—Bridged Interworking

This interworking type provides interoperability between ATM attachment VC and Ethernet attachment VC connected to different PE routers. Bridged encapsulation is used, corresponding to the Bridged (Ethernet) Interworking mechanism.

The interworking function is performed at the PE connected to the ATM attachment VC based on Multiprotocol Encapsulation over ATM Adaptation Layer 5 (Figure 18-4).

Figure 18-4 Network Topology for ATM to Ethernet AToM Bridged Interworking

The advantage of this architecture is that the Ethernet PE (connected to the Ethernet segment) operates similarly to Ethernet like-to-like services.

On the PE with Interworking function, in the direction from the ATM segment to MPLS cloud, the bridged encapsulation (ATM/SNAP header) is discarded and the Ethernet frame is encapsulated with the labels required to go through the pseudowire using the VC type 5 (Ethernet) (Figure 18-5).

In the opposite direction, after the label disposition from the MPLS cloud, Ethernet frames are encapsulated over AAL5 using bridged encapsulation.

Figure 18-5 shows the protocol stack for ATM to Ethernet AToM Bridged Interworking. The ATM side has an encapsulation type of aal5snap.

Figure 18-5 Protocol Stack for ATM to Ethernet AToM Bridged Interworking—Without VLAN Header

ATM AAL5 to Ethernet VLAN 802.1Q AToM—Bridged Interworking

This interworking type provides interoperability between ATM attachment VC and Ethernet VLAN attachment VC connected to different PE routers. Bridged encapsulation is used, corresponding to the Bridged (Ethernet) Interworking mechanism.

The interworking function is performed in the same way as for the ATM to Ethernet Port case, implemented on the PE connected to the ATM attachment VC. The implementation is based on Multiprotocol Encapsulation over ATM Adaptation Layer 5 (see Figure 18-4).

For the PE connected to the Ethernet side, one major difference exists due the existence of the VLAN header in the incoming packet. The PE discards the VLAN header of the incoming frames from the VLAN CE, and the PE inserts a VLAN header into the Ethernet frames traveling from the MPLS cloud. The frames sent on the pseudowire (with VC type 5) are Ethernet frames without the VLAN header.

Encapsulation over ATM Adaptation Layer 5, as shown in Figure 18-6.

Figure 18-6 Protocol Stack for ATM to VLAN AToM Bridged Interworking

Configuration Tasks and Examples

This section describes configuration tasks for and provides examples of two L2VPN technology solutions:

•Local Switching

•AToM

Local Switching

Figure 18-7 shows different LS configurations.

Figure 18-7 Local Switching Model for CLI Commands

Note that LS interworking on the Cisco 10000 router only supports the Bridged Interworking function, also known as Ethernet interworking function.

This section explains the following LS configurations and their examples:

•ATM AAL5 to Ethernet Port

•ATM AAL5 to Ethernet VLAN 802.1Q

ATM AAL5 to Ethernet Port

You can configure the ATM AAL5 to Ethernet Port feature on a PE router using the following steps:

1. config t

2. interface atm slot/subslot/port

3. pvc vpi/vci l2transport

4. encapsulation aal5snap

5. interface [ fastethernet | gigabitethernet ] slot/subslot/port

6. no ip address

7. connect connection-name [ fastethernet | gigabitethernet ] slot/subslot/port atm slot/subslot/port vpi/vci interworking ethernet

Note The order of the interfaces in the connect command is not important.

The following example shows how you can configure the ATM AAL5 to Ethernet Port feature on a PE router:
config t
interface atm 2/0/0
	pvc 0/200 l2transport
	encapsulation aal5snap
interface gigabitethernet 5/1/0
	no ip address
connect atm-enet gigabitethernet 5/1/0 atm 2/0/0 0/200 interworking ethernet
ATM AAL5 to Ethernet VLAN 802.1Q

You can configure the ATM AAL5 to Ethernet VLAN 802.1Q feature on a PE router using the following steps:

1. config t

2. interface atm slot/subslot/port

3. pvc vpi/vci l2transport

4. encapsulation aal5snap

5. interface [ fastethernet | gigabitethernet ] slot/subslot/port.subinterface

6. encapsulation dot1q VLAN-ID

7. connect connection-name [ fastethernet | gigabitethernet ] slot/subslot/port.subinterface atm slot/subslot/port vpi/vci interworking ethernet

Note The order of the interfaces in the connect command is not important.

The following example shows how to configure the ATM AAL5 to Ethernet VLAN 802.1Q feature on a PE router:
config t
interface atm 2/0/0
	pvc 0/200 l2transport
	encapsulation aal5snap
interface gigabitethernet 5/1/0.3
	encapsulation dot1q 2
connect atm-vlan gigabitethernet 5/1/0.3 atm 2/0/0 0/200 interworking ethernet
AToM

Figure 18-8 illustrates different AToM configurations.

Figure 18-8 AToM Model for CLI Commands

Note that AToM interworking for Cisco 10000 routers only supports the bridged interworking function, also known as Ethernet interworking function.

This section explains the following AToM configurations and their examples:

•ATM AAL5 to Ethernet Port

•Configuring ATM AAL5 to Ethernet VLAN 802.1Q

ATM AAL5 to Ethernet Port

You can configure the ATM AAL5 to Ethernet Port feature on a PE1 router using the following steps:

1. config t

2. mpls label protocol ldp

3. interface Loopback<name>

4. ip address local-ip-address local-mask

5. pseudowire-class name

6. encapsulation mpls

7. interworking ethernet

8. interface atm slot/subslot/port

9. pvc vpi/vci l2transport

10. encapsulation aal5snap

11. xconnect remote-ip-address vc-id pw-class name

You can configure the ATM AAL5 to Ethernet Port feature on a PE2 router using the following steps:

1. config t

2. mpls label protocol ldp

3. interface Loopback<name>

4. ip address local-ip-address local-mask

5. pseudowire-class name

6. encapsulation mpls

7. interface [ fastethernet | gigabitethernet ] slot/subslot/port

8. xconnect remote-ip-address vc-id pw-class name

Note The PE2 configuration does not include the interworking ethernet command because it is treated as like-to-like, and because the attachment circuit is already Ethernet port.

The following example shows how to configure the ATM AAL5 to Ethernet Port feature on a PE1 router:
config t
mpls label protocol ldp
interface Loopback100
 ip address 10.0.0.100 255.255.255.255
pseudowire-class atm-eth
 encapsulation mpls
 interworking ethernet
interface atm 2/0/0
 pvc 0/200 l2transport
 encapsulation aal5snap
 xconnect 10.0.0.200 140 pw-class atm-eth
The following example shows how to configure the ATM AAL5 to Ethernet Port feature on a PE2 router:
config t
mpls label protocol ldp
interface Loopback200
 ip address 10.0.0.200 255.255.255.255
pseudowire-class atm-eth
 encapsulation mpls
interface gigabitethernet 5/1/0
 xconnect 10.0.0.100 140 pw-class atm-eth
Configuring ATM AAL5 to Ethernet VLAN 802.1Q

You can configure the ATM AAL5 to Ethernet VLAN 802.1Q feature on a PE1 router using the following steps:

1. config t

2. mpls label protocol ldp

3. interface Loopback<name>

4. ip address local-ip-address local-mask

5. pseudowire-class name

6. encapsulation mpls

7. interworking ethernet

8. interface atm slot/subslot/port

9. pvc vpi/vci l2transport

10. encapsulation aal5snap

11. xconnect remote-ip-address vc-id pw-class name

You can configure the ATM AAL5 to Ethernet VLAN 802.1Q feature on a PE2 router using the following steps:

1. config t

2. mpls label protocol ldp

3. interface Loopback<name>

4. ip address local-ip-address local-mask

5. pseudowire-class name

6. encapsulation mpls

7. interworking ethernet

8. interface [ fastethernet | gigabitethernet ] slot/subslot/port.subinterface

9. encapsulation dot1q VLAN-ID

10. xconnect remote-ip-address vci pw-class name

Note In the case of ATM AAl5 to VLAN, the PE2 configuration does include the interworking ethernet command.

The following example shows how to configure the ATM AAL5 to Ethernet VLAN 802.1Q feature on a PE1 router:
config t
mpls label protocol ldp
interface Loopback100
 ip address 10.0.0.100 255.255.255.255
pseudowire-class atm-vlan
 encapsulation mpls
 interworking ethernet
interface atm 2/0/0
 pvc 0/200 l2transport
 encapsulation aal5snap
 xconnect 10.0.0.200 140 pw-class atm-vlan
The following example shows how to configure the ATM AAL5 to Ethernet VLAN 802.1Q feature on a PE2 router:
config t
mpls label protocol ldp
interface Loopback200
 ip address 10.0.0.200 255.255.255.255
pseudowire-class atm-vlan
 encapsulation mpls
 interworking ethernet
interface gigabitethernet 5/1/0.3
 encapsulation dot1q 1525
 xconnect 10.0.0.100 140 pw-class atm-vlan
Note To verify the L2VPN interworking status and check the statistics, refer to the "Verifying L2VPN Interworking" section.

Ethernet/VLAN to Frame Relay Interworking

The Ethernet VLAN to Frame Relay (FR) Interworking feature is described in the following topics:

•Prerequisites of Ethernet/VLAN to Frame Relay Interworking

•Restrictions for Ethernet/VLAN to Frame Relay Interworking

•FR DLCI to Ethernet Local Switching—Bridged Interworking

•FR DLCI to VLAN 802.1Q Local Switching—Bridged Interworking

•FR DLCI to Ethernet Port AToM—Bridged Interworking

•FR DLCI to Ethernet VLAN 802.1Q AToM—Bridged Interworking

•Configuration Tasks and Examples

Prerequisites of Ethernet/VLAN to Frame Relay Interworking

Before you configure Ethernet/VLAN to Frame Relay Interworking on a network, you must enable Cisco Express Forwarding.

Restrictions for Ethernet/VLAN to Frame Relay Interworking

In Cisco IOS Release 12.2(33)SB, the Ethernet/VLAN to Frame Relay LS has the following restrictions:

•The following translations are only supported and other translations are dropped:

–Ethernet without LAN FCS (0300800080C20007 or 6558)

–Spanning tree (0300800080C2000E or 4242)

•The PVC status signaling works the same way as in the like-to-like case. The PE router reports the PVC status to the CE router based on the availability of the other CE router.

•Only FR DLCI mode is supported. FR port mode is not supported.

•If the Ethernet frame includes a 802.1Q header (VLAN header), due to the type of endpoint attachment (Ethernet port mode), the VLAN header stays in the frame and it is forwarded to the FR CE (Figure 18-9).

Figure 18-9 Protocol Stack for FR to Ethernet Local Switching Bridged Interworking—With VLAN Header

In Cisco IOS Release 12.2(33)SB, the Ethernet/VLAN to Frame Relay AToM has the following restrictions:

•The following translations are only supported and other translations are dropped:

–Ethernet without LAN FCS (0300800080C20007)

–Spanning tree (0300800080C2000E)

•The PE router automatically supports translation of both Cisco and IETF FR encapsulation types coming from the CE, but translates only to IETF when sending to the CE router. This is not a problem for the Cisco CE router, because it can manage IETF encapsulation upon receipt even if it is configured to send a Cisco encapsulation.

•The PVC status signaling works the same way as in the like-to-like case. The PE router reports the PVC status to the CE router based upon the availability of the pseudowire.

•The attachment circuit maximum transmission unit (MTU) must match when connected over MPLS.

•Only FR DLCI mode is supported. FR port mode is not supported.

•If the Ethernet frame includes a 802.1Q header (VLAN header), due to the type of endpoint attachment (Ethernet port mode), the VLAN header stays in the frame across the pseudowire (Figure 18-10).

•FR encapsulation types supported for routed interworking are Cisco and IETF for incoming traffic. However, IETF is also supported for outgoing traffic traveling to the CE only.

Figure 18-10 Protocol Stack for FR to Ethernet AToM Bridged Interworking—With VLAN Header

FR DLCI to Ethernet Local Switching—Bridged Interworking

This interworking type provides interoperability between Frame Relay attachment VC and Ethernet attachment VC connected to the same PE router. For this interworking type, Bridged encapsulation is used, corresponding to Bridged (Ethernet) Interworking mechanism.

•In the Ethernet to FR direction, the PE router forwards the Layer 2 packet without any change to the egress interface, encapsulating the L2 packet over FR using Bridged encapsulation.

•In the FR to Ethernet direction, the FR header and bridged encapsulation are discarded and the L2 packet is sent out with Ethernet encapsulation.

Figure 18-11 shows the protocol stack for FR to Ethernet local switching (bridged interworking).

Figure 18-11 Protocol Stack for FR to Ethernet Local Switching Bridged Interworking

The PE router automatically supports translation of both Cisco and IETF FR encapsulation types traveling from the CE, but translates only to IETF when sending to the CE router. This is not a problem for the Cisco CE router, because it can manage IETF encapsulation on receipt even if it is configured to send a Cisco encapsulation.

FR DLCI to VLAN 802.1Q Local Switching—Bridged Interworking

This interworking type provides interoperability between Frame Relay Attachment VC and Ethernet VLAN Attachment VC connected to the same PE router. For this interworking type the Bridged Encapsulation is used, corresponding to Bridged (Ethernet) Interworking mechanism.

In the case of an Ethernet VLAN attachment, the VLAN ID is a service delimiter, so the VLAN header is not included in the frame to or from the FR CE.

•In the VLAN to FR direction, the PE router discards the VLAN header from the Layer 2 packet. The PE router sends the frame to the FR egress interface after encapsulating the L2 packet over FR using Bridged encapsulation.

•In the FR to VLAN direction, the FR header and bridged encapsulation are discarded and the L2 packet is sent out with a VLAN header inserted, followed by the destination/source MAC addresses.

The protocol stack for FR to Ethernet local switching (bridged interworking) is shown in Figure 18-11.

FR DLCI to Ethernet Port AToM—Bridged Interworking

This interworking type provides interoperability between FR attachment VC and Ethernet attachment VC connected to different PE routers. Bridged encapsulation is used, corresponding to the Bridged (Ethernet) Interworking mechanism.

For an FR to Ethernet Port case, the interworking function is performed at the PE connected to the FR attachment VC based on multiprotocol interconnect over Frame Relay (Figure 18-12). The Interworking is implemented similar to an ATM-to-Ethernet case.

Figure 18-12 Network Topology for FR to Ethernet AToM Bridged Interworking

The advantage of this architecture is that the Ethernet PE (connected to the Ethernet segment) operates similarly to Ethernet like-to-like services: a pseudowire label is assigned to the Ethernet port and then the remote Label Distribution Protocol (LDP) session distributes the labels to its peer PE. Ethernet frames are carried through the MPLS network using Ethernet over MPLS (EoMPLS).

On the PE with Interworking function, in the direction from the FR segment to MPLS cloud, the bridged encapsulation (FR/SNAP header) is discarded and the Ethernet frame is encapsulated with the labels required to go through the pseudowire using the VC type 5 (Ethernet) (Figure 18-13).

In the opposite direction, after the label disposition from the MPLS cloud, Ethernet frames are encapsulated over FR using bridged encapsulation.

The Figure 18-13 shows the protocol stack for FR to Ethernet Bridged Interworking.

Figure 18-13 Protocol Stack for FR to Ethernet AToM Bridged Interworking—Without VLAN Header

FR DLCI to Ethernet VLAN 802.1Q AToM—Bridged Interworking

This interworking type provides interoperability between FR attachment VC and Ethernet VLAN Attachment VC connected to different PE routers. The bridged encapsulation is used, corresponding to the Bridged (Ethernet) Interworking mechanism.

The interworking function is performed in the same way as for FR to Ethernet port case, implemented on the PE connected to the FR attachment VC, based upon a multiprotocol interconnect over Frame Relay (see Figure 18-13).

As in the ATM to VLAN case, one difference exists on Ethernet side due the existence of the VLAN header in the incoming packet. The PE on the VLAN side discards the VLAN header of the incoming frames from the VLAN CE, and the PE inserts a VLAN header into the Ethernet frames traveling from the MPLS cloud. The frames sent on the pseudowire (with VC type 5) are Ethernet frames without the VLAN header.

The Figure 18-14 shows the protocol stack for FR to VLAN AToM Bridged Interworking.

Figure 18-14 Protocol Stack for FR to VLAN AToM Bridged Interworking

Configuration Tasks and Examples

This section describes configuration tasks for and examples of two L2VPN technology solutions

•Local Switching

•AToM

Local Switching

Figure 18-7 shows LS configurations. Note that LS interworking in the Cisco 10000 router only supports the bridged interworking function, also known as Ethernet interworking function.

This section explains the following LS configurations and provides examples:

•FR DLCI to Ethernet Port

•FR DLCI to Ethernet VLAN 802.1Q

FR DLCI to Ethernet Port

You can configure the FR DLCI to Ethernet port feature on a router using the following steps:

1. config t

2. frame-relay switching

3. interface serial slot/subslot/port[:channel | .channel]

4. encapsulation frame-relay

5. frame-relay intf-type dce

6. frame-relay interface-dlci DLCI switched

7. interface [ fastethernet | gigabitethernet ] slot/subslot/port

8. no ip address

9. connect connection-name [ fastethernet | gigabitethernet ] slot/subslot/port serial slot/subslot/port[:channel | .channel] interworking ethernet

Note The order of the interfaces in the connect command is not important.

The following example shows how you can configure the FR DLCI to Ethernet Port feature on a router:
config t
frame-relay switching
interface serial 2/0/0:1
	encapsulation frame-relay
	frame-relay intf-type dce
	frame-relay interface-dlci 100 switched
interface gigabitethernet 5/1/0
	no ip address
connect atm-enet gigabitethernet 5/1/0 serial 2/0/0:1 100 interworking ethernet
FR DLCI to Ethernet VLAN 802.1Q

You can configure the FR DLCI to Ethernet VLAN 802.1Q feature on a router using the following steps:

1. config t

2. frame-relay switching

3. interface serial slot/subslot/port[:channel | .channel]

4. encapsulation frame-relay

5. frame-relay intf-type dce

6. frame-relay interface-dlci DLCI switched

7. interface [ fastethernet | gigabitethernet ] slot/subslot/port.subinterface

8. encapsulation dot1q VLAN-ID

9. connect connection-name [ fastethernet | gigabitethernet ] slot/subslot/port.subinterface serial slot/subslot/port[:channel | .channel] interworking ethernet

Note The order of the interfaces in the connect command is not important.

The following example shows how you can configure the FR DLCI to Ethernet VLAN 802.1Q feature on a router:
config t
frame-relay switching
interface serial 2/0/0:1
	encapsulation frame-relay
	frame-relay intf-type dce
	frame-relay interface-dlci 100 switched
interface gigabitethernet 5/1/0.3
	encapsulation dot1q 2
connect fr-vlan gigabitethernet 5/1/0.3 serial 2/0/0:1 100 interworking ethernet
AToM

Figure 18-8 illustrates different AToM configurations. Note that AToM interworking in the Cisco 10000 router only supports the bridged interworking function, also known as Ethernet interworking function.

This section explains the following AToM configurations and provides examples:

•FR DLCI to Ethernet Port

•FR DLCI to Ethernet VLAN 802.1Q

FR DLCI to Ethernet Port

You can configure the FR DLCI to Ethernet port feature on a PE1 router using the following steps:

1. config t

2. mpls label protocol ldp

3. interface Loopback<name>

4. ip address local-ip-address local-mask

5. pseudowire-class name

6. encapsulation mpls

7. interworking ethernet

8. frame-relay switching

9. interface serial slot/subslot/port[:channel | .channel]

10. encapsulation frame-relay

11. frame-relay interface-dlci DLCI switched

12. connect mpls serial slot/subslot/port[:channel | .channel] DLCI l2transport

13. xconnect remote-ip-address vc-id pw-class name

You can configure the FR DLCI to Ethernet port feature on a PE2 router using the following steps:

1. config t

2. mpls label protocol ldp

3. interface Loopback<name>

4. ip address local-ip-address local-mask

5. pseudowire-class name

6. encapsulation mpls

7. interface [ fastethernet | gigabitethernet ] slot/subslot/port

8. xconnect remote-ip-address vc-id pw-class name

Note The PE2 configuration does not include the interworking ethernet command because it is treated as like-to-like, as the attachment circuit is already an Ethernet port.

The following example shows how to configure the FR DLCI to Ethernet port feature on a PE1 router:
config t
mpls label protocol ldp
interface Loopback100
 ip address 10.0.0.100 255.255.255.255
pseudowire-class fr-eth
 encapsulation mpls
 interworking ethernet
frame-relay switching
interface serial 2/0/0:1
 encapsulation frame-relay
 frame-relay intf-type dce
connect mpls serial 2/0/0:1 567 l2transport
 xconnect 10.0.0.200 150 pw-class fr-eth
The following example shows how to configure the FR DLCI to an Ethernet port feature on a PE2 router:
config t
mpls label protocol ldp
interface Loopback200
 ip address 10.0.0.200 255.255.255.255
pseudowire-class fr-eth
 encapsulation mpls
interface gigabitethernet 5/1/0
 xconnect 10.0.0.100 150 pw-class fr-eth
FR DLCI to Ethernet VLAN 802.1Q

To configure the FR DLCI to Ethernet VLAN 802.1Q feature on a PE1 router, use the following steps:

1. config t

2. mpls label protocol ldp

3. interface Loopback<name>

4. ip address local-ip-address local-mask

5. pseudowire-class name

6. encapsulation mpls

7. interworking ethernet

8. frame-relay switching

9. interface serial slot/subslot/port[:channel | .channel]

10. encapsulation frame-relay

11. frame-relay intf-type dce

12. frame-relay interface-dlci DLCI switched

13. connect mpls serial slot/subslot/port[:channel | .channel] DLCI l2transport

14. xconnect remote-ip-address vc-id pw-class name

To configure the FR DLCI to Ethernet VLAN 802.1Q feature on a PE2 router, use the following steps:

1. config t

2. mpls label protocol ldp

3. interface Loopback<name>

4. ip address local-ip-address local-mask

5. pseudowire-class name

6. encapsulation mpls

7. interworking ethernet

8. interface [ fastethernet | gigabitethernet ] slot/subslot/port.subinterface

9. encapsulation dot1q VLAN-ID

10. xconnect remote-ip-address vc-id pw-class name

Note In the case of an FR DLCI to VLAN, the PE2 configuration includes the interworking ethernet command.

The following example shows how to configure the FR DLCI to Ethernet VLAN 802.1Q feature on a PE1 router:
config t
mpls label protocol ldp
interface Loopback100
 ip address 10.0.0.100 255.255.255.255
pseudowire-class fr-vlan
 encapsulation mpls
 interworking ethernet
frame-relay switching
interface serial 2/0/0:1
 encapsulation frame-relay
 frame-relay intf-type dce
connect mpls serial 2/0/0:1 567 l2transport
 xconnect 10.0.0.200 150 pw-class fr-vlan
The following example shows how to configure the FR DLCI to Ethernet VLAN 802.1Q feature on a PE2 router:
config t
mpls label protocol ldp
interface Loopback200
 ip address 10.0.0.200 255.255.255.255
pseudowire-class fr-vlan
 encapsulation mpls
 interworking ethernet
interface gigabitethernet 5/1/0.3
 encapsulation dot1q 1525
 xconnect 10.0.0.100 150 pw-class fr-vlan
Note To verify the L2VPN interworking status and check the statistics, refer to the "Verifying L2VPN Interworking" section.

Verifying L2VPN Interworking

To verify the L2VPN status - local switching, use the following commands:

•show connection [all | name | id | elements | port ]

•show pxf cpu atom [circuits | interface | vcci]

To view the L2VPN statistics - local switching, use the following command:

•show pxf cpu statistics atom

To verify the L2VPN status - AToM, use the following commands:

•show connection [all | name | id | elements | port ]

•show xconnect [ all | interface | peer ]

•show mpls l2transport [binding | checkpoint | hw-capability | summary | vc ]

•show mpls infrastructure lfd pseudowire vcid

•show pxf cpu atom [circuits | interface | vcci]

To verify the L2VPN statistics - AToM, use the following commands:

•show pxf cpu statistics atom

•show pxf cpu subblocks