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Layer 2 Circuit Configuration Examples

This section contains configuration examples and commands you can issue to verify Layer 2 circuit configurations:

Example: Ethernet-Based Layer 2 Circuit Configuration

Figure 73: Ethernet-Based Layer 2 Circuit Topology Diagram

Image g017138.gif

In Figure 73, a Layer 2 circuit is established between routers PE1 and PE2 to deliver Layer 2 traffic between customer routers CE1 and CE2. A Layer 2 circuit VC connection is configured on the PE routers only. No special configuration is required on the CE routers, and the provider core P0 router only requires MPLS and LDP on the appropriate interfaces to enable labels to be shared between the PE routers.

On Router CE1, configure the Fast Ethernet interface to handle VLAN traffic. Be sure to use the same VLAN ID both here and on the Fast Ethernet interface of Router CE2.

Router CE1

[edit]
interfaces {
fe-1/1/2 {
description "to PE1 fe-1/1/0";
vlan-tagging;
unit 600 {
vlan-id 600; # Be sure this VLAN ID matches the VLAN ID of your CE neighbor.
family inet {
address 10.1.1.1/24;
}
}
}
}

On Router PE1, configure the Ethernet-based CE-facing interface with the CCC encapsulation type of your choice. If you use VLAN CCC, include the vlan-tagging statement at the [edit interfaces ethernet-interface-fpc/pic /port] hierarchy level. Also, include the encapsulation vlan-ccc statement at both the [edit interfaces ethernet-interface-fpc/pic/port] and [edit interfaces ethernet-interface-fpc /pic/port unit unit-number] hierarchy levels.

Establish your Layer 2 circuit with configuration of the l2circuit statement at the [edit protocols] hierarchy level. Remember to include in your Layer 2 circuit configuration the IP address of your remote PE neighbor (usually the loopback address of the neighbor), the interface connected to the CE router, and a virtual circuit identifier for this VC. Then, configure MPLS, LDP, and an IGP (such as OSPF) to enable signaling for your Layer 2 circuit.

Router PE1

[edit]
interfaces {
so-0/1/0 {
description "to P0 so-0/0/0";
unit 0 {
family inet {
address 192.168.245.22/30;
}
family mpls; # Include the MPLS family on core-facing interfaces.
}
}
fe-1/1/0 {
description "to CE1 fe-1/1/2";
vlan-tagging;
encapsulation vlan-ccc; # Configure CCC encapsulation on CE-facing interfaces.
unit 600 {
encapsulation vlan-ccc; # Enable this encapsulation on the logical interface.
vlan-id 600;
}
}
lo0 {
unit 0 {
family inet {
address 10.245.14.173/32;
}
}
}
}
protocols {
ospf {
traffic-engineering;
area 0.0.0.0 {
interface so-0/1/0.0;
interface lo0.0;
}
}
ldp { # LDP is required as the signaling protocol for Layer 2 circuits.
interface so-0/1/0.0;
interface lo0.0;# You must include the loopback address in LDP.
}
l2circuit {
neighbor 10.245.14.179 { # This points to the loopback of the PE neighbor.
interface fe-1/1/0.600 { # Here you include the local CE-facing interface.
virtual-circuit-id 5; # Be sure this ID matches the ID of your PE neighbor.
}
}
}
}

On Router P0, configure LDP, MPLS, and OSPF on the interfaces connected to the PE routers. The core router provides the MPLS backbone needed to tunnel Layer 2 traffic from the ingress PR router to the egress PE router.

Router P0

[edit]
interfaces {
so-0/0/0 {
description "to PE1 so-0/1/0";
unit 0 {
family inet {
address 192.168.245.21/30;
}
family mpls; # Include the MPLS family on core interfaces.
}
}
t3-0/2/1 {
description "to PE2 t3-0/1/0";
unit 0 {
family inet {
address 192.168.245.17/30;
}
family mpls; # Include the MPLS family on core interfaces.
}
}
lo0 {
unit 0 {
family inet {
address 10.245.14.171/32;
}
}
}
}
protocols {
ospf {
traffic-engineering;
area 0.0.0.0 {
interface so-0/0/0.0;
interface t3-0/2/1.0;
}
}
ldp { # LDP is required as the signaling protocol for Layer 2 circuits.
interface so-0/0/0.0;
interface t3-0/2/1.0;
}
}

On Router PE2, complete the Layer 2 circuit by configuring statements to match those previously set on Router PE1. Configure the Ethernet-based CE-facing interface with CCC encapsulation. Again, you must include the vlan-tagging statement at the [edit interfaces ethernet-interface-fpc/pic/port] hierarchy level when you use VLAN CCC. Also, include the encapsulation vlan-ccc statement at both the [edit interfaces ethernet-interface-fpc/pic/port] and [edit interfaces ethernet-interface-fpc/pic/port unit unit-number] hierarchy levels.

Establish your Layer 2 circuit with configuration of the l2circuit statement at the [edit protocols] hierarchy level. Remember to include in your Layer 2 circuit configuration the IP address of your remote PE neighbor (Router PE1), the virtual circuit identifier previously configured on Router PE1, and the interface connected to the CE router. Finally, configure MPLS, LDP, and OSPF to enable signaling for your Layer 2 circuit.

Router PE2

[edit]
interfaces {
t3-0/1/0 {
description "P0 t3-0/2/1";
unit 0 {
family inet {
address 192.168.245.18/30;
}
family mpls; # Include the MPLS family on core-facing interfaces.
}
}
fe-0/2/0 {
description "to CE2 fe-0/2/0";
vlan-tagging;
encapsulation vlan-ccc; # Configure CCC encapsulation on CE-facing interfaces.
unit 600 {
encapsulation vlan-ccc; # Enable this encapsulation on the logical interface.
vlan-id 600;
}
}
lo0 {
unit 0 {
family inet {
address 10.245.14.179/32;
}
}
}
}
protocols {
ospf {
traffic-engineering;
area 0.0.0.0 {
interface t3-0/1/0.0;
interface lo0.0;
}
}
ldp { # LDP is required as the signaling protocol for Layer 2 circuits.
interface t3-0/1/0.0;
interface lo0.0; # You must include the loopback address in LDP.
}
l2circuit {
neighbor 10.245.14.173 { # This points to the loopback of the PE neighbor.
interface fe-0/2/0.600 { # Here you include the local CE-facing interface.
virtual-circuit-id 5; # Be sure this ID matches the ID of your PE neighbor.
}
}
}
}

On Router CE2, configure the Fast Ethernet interface to handle VLAN traffic. Be sure to use the same VLAN ID on this interface as the one seen on the Fast Ethernet interface of Router CE1.

Router CE2

[edit]
interfaces {
fe-0/2/0 {
description "to PE2 fe-0/2/0";
vlan-tagging;
unit 600 {
vlan-id 600; # Be sure this VLAN ID matches the VLAN ID of your CE neighbor.
family inet {
address 10.1.1.2/24;
}
}
}
}

Verifying Your Work

To verify proper operation of Layer 2 circuits, use the following commands:

In addition to displaying bindings for IP prefixes, the show ldp database command also displays the bindings for the Layer 2 FECs.

The following sections show the output of these commands used with the configuration example:

Router PE1 Status


user@PE1> show l2circuit connections 
Layer-2 Circuit Connections:

Legend for connection status (St)   Legend for interface status
EI -- encapsulation invalid         UP -- operational
MM -- mtu mismatch                  Dn -- down
EM -- encapsulation mismatch        NP -- no present
OL -- no outgoing label             DS -- disabled
Dn -- down                          WE -- wrong encapsulation
VC-Dn -- Virtual circuit Down       UN -- uninitialized
UP -- operational
XX -- unknown

Neighbor: 10.245.14.179
    Interface                 Type  St     Time last up          # Up trans
    fe-1/1/0.600 (vc 5)       rmt   Up     Nov 30 00:54:55 2001           1
      Local interface: fe-1/1/0.600, Status: Up,  Encapsulation: VLAN
      Remote PE: 10.245.14.179,  Negotiated control-word: Yes (Null)
      Incoming label: 100007, Outgoing label: 100000

user@PE1>  show ldp database

Input label database, 10.245.14.173:0-10.245.14.171:0
  Label     Prefix
 100019     10.245.14.173/32
 100020     10.245.14.179/32
      3     10.245.14.171/32

Output label database, 10.245.14.173:0-10.245.14.171:0
  Label     Prefix
 100009     10.245.14.179/32
      3     10.245.14.173/32
 100008     10.245.14.171/32

Input label database, 10.245.14.173:0-10.245.14.179:0
  Label     Prefix
 100001     10.245.14.171/32
 100002     10.245.14.173/32
      3     10.245.14.179/32
 100000     L2CKT VLAN VC 5

Output label database, 10.245.14.173:0-10.245.14.179:0
  Label     Prefix
 100009     10.245.14.179/32
      3     10.245.14.173/32
 100008     10.245.14.171/32
 100007     L2CKT VLAN VC 5

Router P0 Status


user@P0> show ldp database 
Input label database, 10.245.14.171:0-10.245.14.173:0
  Label     Prefix
      3     10.245.14.173/32
 100009     10.245.14.179/32
 100008     10.245.14.171/32

Output label database, 10.245.14.171:0-10.245.14.173:0
  Label     Prefix
 100019     10.245.14.173/32
 100020     10.245.14.179/32
      3     10.245.14.171/32

Input label database, 10.245.14.171:0-10.245.14.179:0
  Label     Prefix
 100001     10.245.14.171/32
      3     10.245.14.179/32
 100002     10.245.14.173/32

Output label database, 10.245.14.171:0-10.245.14.179:0
  Label     Prefix
 100019     10.245.14.173/32
 100020     10.245.14.179/32
      3     10.245.14.171/32

Router PE2 Status


user@PE2> show l2circuit connections 
Layer-2 Circuit Connections:

Legend for connection status (St)   Legend for interface status
EI -- encapsulation invalid         UP -- operational
MM -- mtu mismatch                  Dn -- down
EM -- encapsulation mismatch        NP -- no present
OL -- no outgoing label             DS -- disabled
Dn -- down                          WE -- wrong encapsulation
VC-Dn -- Virtual circuit Down       UN -- uninitialized
UP -- operational
XX -- unknown

Neighbor: 10.245.14.173
    Interface                 Type  St     Time last up          # Up trans
    fe-0/2/0.600 (vc 5)       rmt   Up     Nov 30 00:54:54 2001           1
      Local interface: fe-0/2/0.600, Status: Up,  Encapsulation: VLAN
      Remote PE: 10.245.14.173,  Negotiated control-word: Yes (Null)
      Incoming label: 100000, Outgoing label: 100007

user@PE2>  show ldp database

Input label database, 10.245.14.179:0-10.245.14.171:0
  Label     Prefix
 100019     10.245.14.173/32
      3     10.245.14.171/32
 100020     10.245.14.179/32

Output label database, 10.245.14.179:0-10.245.14.171:0
  Label     Prefix
 100001     10.245.14.171/32
 100002     10.245.14.173/32
      3     10.245.14.179/32

Input label database, 10.245.14.179:0-10.245.14.173:0
  Label     Prefix
      3     10.245.14.173/32
 100008     10.245.14.171/32
 100009     10.245.14.179/32
 100007     L2CKT VLAN VC 5

Output label database, 10.245.14.179:0-10.245.14.173:0
  Label     Prefix
 100001     10.245.14.171/32
 100002     10.245.14.173/32
      3     10.245.14.179/32
 100000     L2CKT VLAN VC 5

Example: SONET/SDH-Based Layer 2 Circuit Configuration

Figure 74: SONET/SDH-Based Layer 2 Circuit Topology Diagram

Image g017216.gif

In this second Layer 2 circuit example shown in Figure 74, you configure a Layer 2 circuit for a SONET/SDH interface encapsulated with PPP.

On Router CE1, configure the SONET/SDH interface to handle PPP traffic. Be sure to use the same IP address prefix both here and on the SONET/SDH interface of Router CE2.

Router CE1

[edit]
interfaces {
so-0/0/1 {
description "to PE1 so-0/0/0";
encapsulation ppp;
unit 0 {
family inet {
address 10.1.1.1/30;
}
}
}
}

On Router PE1, configure the PPP-based CE-facing interface with PPP CCC encapsulation. Establish your Layer 2 circuit with configuration of the l2circuit statement at the [edit protocols] hierarchy level. Remember to include in your Layer 2 circuit configuration the IP address of your remote PE neighbor (usually the loopback address of the neighbor), the interface connected to the CE router, and a virtual circuit identifier for this VC. Then, configure MPLS, LDP, and an IGP (such as OSPF) to enable signaling for your Layer 2 circuit.

Router PE1

[edit]
interfaces {
so-0/0/0 {
description "to CE1 so-0/0/1";
encapsulation ppp-ccc; # Configure CCC encapsulation on CE-facing interfaces.
unit 0;
}
so-0/1/0 {
description "to P0 so-0/0/0";
unit 0 {
family inet {
address 192.168.245.22/30;
}
family mpls; # Include the MPLS family on core-facing interfaces.
}
}
lo0 {
unit 0 {
family inet {
address 10.255.145.126/32;
}
}
}
}
protocols {
ospf {
traffic-engineering;
area 0.0.0.0 {
interface so-0/1/0.0;
interface lo0.0;
}
}
ldp { # LDP is required as the signaling protocol for Layer 2 circuits.
interface so-0/1/0.0;
interface lo0.0;
}
l2circuit {
neighbor 10.255.145.130 { # This points to the loopback of the PE neighbor.
interface so-0/0/0.0 { # Here you include the local CE-facing interface.
virtual-circuit-id 1; # Be sure this ID matches the ID of your PE neighbor.
}
}
}
}

On Router P0, configure LDP, MPLS, and OSPF on the interfaces connected to the PE routers. The core router provides the MPLS backbone needed to tunnel Layer 2 traffic from the ingress PR router to the egress PE router.

Router P0

[edit]
interfaces {
so-0/0/0 {
description "to PE1 so-0/1/0";
unit 0 {
family inet {
address 192.168.245.21/30;
}
family mpls; # Include the MPLS family on core interfaces.
}
}
so-0/2/1 {
description "to PE2 so-1/1/0";
unit 0 {
family inet {
address 192.168.245.17/30;
}
family mpls; # Include the MPLS family on core interfaces.
}
}
lo0 {
unit 0 {
family inet {
address 10.255.145.129/32;
}
}
}
}
protocols {
ospf {
traffic-engineering;
area 0.0.0.0 {
interface so-0/0/0.0;
interface so-0/2/1.0;
}
}
ldp { # LDP is required as the signaling protocol for Layer 2 circuits.
interface so-0/0/0.0;
interface so-0/2/1.0;
}
}

On Router PE2, complete the Layer 2 circuit by configuring statements to match those previously set on Router PE1. Configure the PPP-based CE-facing interface with PPP CCC encapsulation. Complete your Layer 2 circuit with configuration of the l2circuit statement at the [edit protocols] hierarchy level. Remember to include in your Layer 2 circuit configuration the IP address of your remote PE neighbor (Router PE1), the interface connected to the CE router, and a virtual circuit identifier for this VC. Then, configure MPLS, LDP, and an IGP (such as OSPF) to enable signaling for your Layer 2 circuit.

Router PE2

[edit]
interfaces {
so-1/0/0 {
description "to CE1 so-1/0/1";
encapsulation ppp-ccc; # Configure CCC encapsulation on CE-facing interfaces.
unit 0;
}
so-1/1/0 {
description "to P0 so-0/2/1";
unit 0 {
family inet {
address 192.168.245.18/30;
}
family mpls; # Include the MPLS family on core-facing interfaces.
}
}
lo0 {
unit 0 {
family inet {
address 10.255.145.130/32;
}
}
}
}
protocols {
ospf {
traffic-engineering;
area 0.0.0.0 {
interface so-1/1/0.0;
interface lo0.0;
}
}
ldp { # LDP is required as the signaling protocol for Layer 2 circuits.
interface so-1/1/0.0;
interface lo0.0;
}
l2circuit {
neighbor 10.255.145.126 { # This points to the loopback of the PE neighbor.
interface so-1/0/0.0 { # Here you include the local CE-facing interface.
virtual-circuit-id 1; # Be sure this ID matches the ID of your PE neighbor.
}
}
}
}

On Router CE2, configure the SONET/SDH interface to handle PPP traffic. Be sure to use the same IP address prefix both here and on the SONET/SDH interface of Router CE1.

Router CE2

[edit]
interfaces {
so-1/0/1 {
description "to PE2 so-1/0/0";
encapsulation ppp;
unit 0 {
family inet {
address 10.1.1.2/30;
}
}
}
}

Verifying Your Work

To verify proper operation of Layer 2 circuits, use the following commands:

The following section shows the output of these commands used with the configuration example:


user@PE1> show l2circuit connections
Layer-2 Circuit Connections:

Legend for connection status (St)
EI -- encapsulation invalid      NP -- interface not present
MM -- mtu mismatch               Dn -- down
EM -- encapsulation mismatch     VC-Dn -- Virtual circuit Down
CM -- control-word mismatch      Up -- operational
OL -- no outgoing label          XX -- unknown
NC -- intf encaps not CCC/TCC

Legend for interface status
Up -- operational
Dn -- down

Neighbor: 10.255.145.130
     Interface                 Type  St     Time last up          # Up trans
     so-0/0/0.0 (vc 1)         rmt   Up     Jan 26 14:13:54 2003           1
       Local interface: so-0/0/0.0, Status: Up, Encapsulation: PPP
       Remote PE: 10.255.145.130, Negotiated control-word: Yes (Null)
       Incoming label: 100000, Outgoing label: 100000

user@PE1>  show ldp database l2circuit
Input label database, 10.255.145.126:0--10.255.145.130:0
   Label     Prefix
  100000     L2CKT CtrlWord PPP VC 1

Output label database, 10.255.145.126:0--10.255.145.130:0
   Label     Prefix
  100000     L2CKT CtrlWord PPP VC 1

user@PE1> show ldp database l2circuit detail
Input label database, 10.255.145.126:0--10.255.145.130:0
   Label     Prefix
  100000     L2CKT CtrlWord PPP VC 1
             State: Active
             Age: 5:37

Output label database, 10.255.145.126:0--10.255.145.130:0
   Label     Prefix
  100000     L2CKT CtrlWord PPP VC 1
             State: Active
             Age: 5:37

user@PE1> show route table mpls.0

mpls.0: 7 destinations, 7 routes (7 active, 0 holddown, 0 hidden)
Restart Complete
+ = Active Route, - = Last Active, * = Both
0                  *[MPLS/0] 00:05:04, metric 1
                       Receive
1                  *[MPLS/0] 00:05:04, metric 1
                       Receive
2                  *[MPLS/0] 00:05:04, metric 1
                       Receive
100000             *[L2VPN/7] 00:04:50
                     > via so-0/0/0.0, Pop       Offset: 4
100016             *[LDP/9] 00:04:52, metric 1
                     > via so-0/1/0.0, Pop
100016(S=0)        *[LDP/9] 00:04:52, metric 1
                     > via so-0/1/0.0, Pop
so-0/0/0.0         *[L2VPN/7] 00:04:50
                     > via so-0/1/0.0, Push 100000 Offset: -4

Example: ATM2 IQ-Based Layer 2 Circuit Configuration

Figure 75: ATM2 IQ-Based Layer 2 Circuit Topology Diagram

Image g017217.gif

Figure 75 shows a similar network topology to our previous two examples. In this example, Routers PE1 and PE2 use ATM cell-relay mode on a CE-facing interface and ATM AAL5 mode on a second CE-facing interface.

On Router CE1, configure the ATM2 IQ interfaces to handle ATM traffic. Interface at-0/0/1 handles standard ATM traffic while interface at-0/0/2 handles AAL5 traffic.

Router CE1

[edit]
interfaces {
at-0/0/1 {
description "to PE1 at-0/1/0";
atm-options {
pic-type atm2; # Layer 2 circuits are compatible with
vpi 0; # ATM2 IQ interfaces.
}
unit 0 {
vci 32;
family inet {
address 10.1.1.1/30;
}
}
}
at-0/0/2 {
description "to PE1 at-1/2/0";
atm-options {
pic-type atm2; # Layer 2 circuits are compatible with
vpi 0; # ATM2 IQ interfaces.
}
unit 0 {
encapsulation atm-vc-mux;
vci 32;
family inet {
address 10.2.2.1/30;
}
}
}
}

On Router PE1, configure the ATM2 IQ-based CE-facing interfaces: one with ATM cell-relay mode CCC encapsulation and the other with ATM VC multiplexing CCC encapsulation. Also enable the corresponding Layer 2 circuit modes at the [edit chassis] hierarchy level. In this case, you must configure cell-relay mode on Physical Interface Card (PIC) 1 in Flexible PIC Concentrator (FPC) 0 and AAL5 mode on PIC 2 in FPC 1.

Establish your Layer 2 circuit with configuration of the l2circuit statement at the [edit protocols] hierarchy level. Remember to include in your Layer 2 circuit configuration the IP address of your remote PE neighbor (usually the loopback address of the neighbor), the interfaces connected to the CE router, and a virtual circuit identifier for each VC. In this case, you will establish one VC for cell-relay mode traffic and a second VC for AAL5 traffic. Then, configure MPLS, LDP, and an IGP (such as OSPF) to enable signaling for your Layer 2 circuit.

Router PE1

[edit]
chassis {
fpc 0 {
pic 1 {
atm-l2circuit-mode {
cell; # This dedicates FPC 0 PIC 1 to cell-relay mode.
}
}
}
fpc 1 {
pic 2 {
atm-l2circuit-mode {
aal5; # This dedicates FPC 1 PIC 2 to AAL5 mode.
}
}
}
}
interfaces {
at-0/1/0 {
description "to CE1 at-0/0/1";
encapsulation atm-ccc-cell-relay; # Cell-relay requires cell-relay encapsulation.
atm-options {
cell-bundle-size 4; # This sets the cell bundle size for the interface.
pic-type atm2; # Layer 2 circuits are compatible with
vpi 0; # ATM2 IQ interfaces.
}
unit 0 {
encapsulation atm-ccc-cell-relay; # Encapsulation for the logical interface.
vci 32;
cell-bundle-size 10; # The cell bundle size for the logical interface overrides
}       # the physical interface setting.
}
at-1/2/0 {
description "to CE1 at-0/0/2";
atm-options {
pic-type atm2; # Layer 2 circuits are compatible with
vpi 0; # ATM2 IQ interfaces.
}
unit 0 {
encapsulation atm-ccc-vc-mux; # AAL5 requires CCC VC MUX encapsulation.
vci 32;
}
}
so-0/1/0 {
description "to P0 so-0/0/0";
unit 0 {
family inet {
address 192.168.245.22/30;
}
family mpls; # Include the MPLS family on core-facing interfaces.
}
}
lo0 {
unit 0 {
family inet {
address 10.255.17.2/32;
}
}
}
}
protocols {
ospf {
traffic-engineering;
area 0.0.0.0 {
interface so-0/1/0.0;
interface lo0.0;
}
}
ldp { # LDP is required as the signaling protocol for Layer 2 circuits.
interface so-0/1/0.0;
interface lo0.0;
}
l2circuit {
neighbor 10.255.17.4 { # This points to the loopback of the PE neighbor.
interface at-0/1/0.32 { # Here you include the local CE-facing interface.
virtual-circuit-id 1; # Be sure this ID matches the ID of your PE neighbor.
}
}
neighbor 10.255.17.4 { # This points to the loopback of the PE neighbor.
interface at-1/2/0.32 { # Here you include the local CE-facing interface.
virtual-circuit-id 2; # Be sure this ID matches the ID of your PE neighbor.
}
}
}
}

On Router P0, configure LDP, MPLS, and OSPF on the interfaces connected to the PE routers. The core router provides the MPLS backbone needed to tunnel Layer 2 traffic from the ingress PR router to the egress PE router.

Router P0

[edit]
interfaces {
so-0/0/0 {
description "to PE1 so-0/1/0";
unit 0 {
family inet {
address 192.168.245.21/30;
}
family mpls; # Include the MPLS family on core interfaces.
}
}
so-0/2/1 {
description "to PE2 so-1/1/0";
unit 0 {
family inet {
address 192.168.245.17/30;
}
family mpls; # Include the MPLS family on core interfaces.
}
}
lo0 {
unit 0 {
family inet {
address 10.255.17.3/32;
}
}
}
}
protocols {
ospf {
traffic-engineering;
area 0.0.0.0 {
interface so-0/0/0.0;
interface so-0/2/1.0;
}
}
ldp { # LDP is required as the signaling protocol for Layer 2 circuits.
interface so-0/0/0.0;
interface so-0/2/1.0;
}
}

On Router PE2, complete the Layer 2 circuit by configuring statements to match those previously set on Router PE1.

Configure the ATM2 IQ-based CE-facing interfaces: one with ATM cell-relay mode CCC encapsulation and the other with ATM VC multiplexing CCC encapsulation. Also enable the corresponding Layer 2 circuit modes at the [edit chassis] hierarchy level. In this case, you must configure cell-relay mode on PIC 1 in FPC 0 and AAL5 mode on PIC 2 in FPC 1.

Complete your Layer 2 circuit with configuration of the l2circuit statement at the [edit protocols] hierarchy level. Remember to include in your Layer 2 circuit configuration the IP address of your remote PE neighbor (Router PE1), the interfaces connected to the CE router, and a virtual circuit identifier for each VC. In this case, you will establish one VC for cell-relay mode traffic and a second VC for AAL5 traffic. Then, configure MPLS, LDP, and an IGP (such as OSPF) to enable signaling for your Layer 2 circuit.

Router PE2

[edit]
chassis {
fpc 0 {
pic 1 {
atm-l2circuit-mode {
cell; # This dedicates FPC 0 PIC 1 to cell-relay mode.
}
}
}
fpc 1 {
pic 2 {
atm-l2circuit-mode {
aal5; # This dedicates FPC 1 PIC 2 to AAL5 mode.
}
}
}
}
interfaces {
at-0/1/1 {
description "to CE2 at-1/0/1";
encapsulation atm-ccc-cell-relay; # Cell-relay requires cell-relay encapsulation.
atm-options {
cell-bundle-size 4; # This sets the cell bundle size for the physical interface.
pic-type atm2; # Layer 2 circuits are compatible with
vpi 0; # ATM2 IQ interfaces.
}
unit 0 {
encapsulation atm-ccc-cell-relay; # Also configure the encapsulation
vci 32; # on the logical interface.
cell-bundle-size 10; # The cell bundle size for the logical interface overrides
}          # the physical interface setting.
}
at-1/2/1 {
description "to CE2 at-1/0/2";
atm-options {
pic-type atm2; # Layer 2 circuits are compatible with
vpi 0; # ATM2 IQ interfaces.
}
unit 0 {
encapsulation atm-ccc-vc-mux; # AAL5 requires CCC VC MUX encapsulation.
vci 32;
}
}
so-1/1/0 {
description "to P0 so-0/2/1";
unit 0 {
family inet {
address 192.168.245.18/30;
}
family mpls; # Include the MPLS family on core-facing interfaces.
}
}
lo0 {
unit 0 {
family inet {
address 10.255.17.4/32;
}
}
}
}
protocols {
ospf {
traffic-engineering;
area 0.0.0.0 {
interface so-1/1/0.0;
interface lo0.0;
}
}
ldp {    # LDP is required as the signaling protocol for Layer 2 circuits.
interface so-1/1/0.0;
interface lo0.0;
}
l2circuit {
neighbor 10.255.17.2 { # This points to the loopback of the PE neighbor.
interface at-0/1/1.32 { # Here you include the local CE-facing interface.
virtual-circuit-id 1; # Be sure this ID matches the ID of your PE neighbor.
}
}
neighbor 10.255.17.2 { # This points to the loopback of the PE neighbor.
interface at-1/2/1.32 { # Here you include the local CE-facing interface.
virtual-circuit-id 2; # Be sure this ID matches the ID of your PE neighbor.
}
}
}
}

On Router CE2, configure the ATM2 IQ interfaces to handle ATM traffic. Interface at-1/0/1 handles standard ATM traffic while interface at-1/0/2 handles AAL5 traffic.

Router CE2

[edit]
interfaces {
at-1/0/1 {
description "to PE2 at-0/1/1";
atm-options {
pic-type atm2; # Layer 2 circuits are compatible with
vpi 0;    # ATM2 IQ interfaces.
}
unit 0 {
vci 32;
family inet {
address 10.1.1.2/30;
}
}
}
at-1/0/2 {
description "to PE2 at-1/2/1";
atm-options {
pic-type atm2; # Layer 2 circuits are compatible with
vpi 0;   # ATM2 IQ interfaces.
}
unit 0 {
encapsulation atm-vc-mux;
vci 32;
family inet {
address 10.2.2.2/30;
}
}
}
}

Verifying Your Work

To verify proper operation of Layer 2 circuits, use the following commands:

This is what the operational command output looks like for cell-relay mode on Router PE1:


user@PE1> show l2circuit connections 
Layer-2 Circuit Connections:

Legend for connection status (St)
EI -- encapsulation invalid      NP -- interface not present
MM -- mtu mismatch               Dn -- down
EM -- encapsulation mismatch     VC-Dn -- Virtual circuit Down
CM -- control-word mismatch      Up -- operational
OL -- no outgoing label          XX -- unknown
NC -- intf encaps not CCC/TCC

Legend for interface status
Up -- operational
Dn -- down

Neighbor: 10.255.17.4
    Interface                 Type  St     Time last up          # Up trans
    at-0/1/0.0 (vc 32)        rmt   Up     Jan 22 15:15:52 2003           1
      Local interface: at-0/1/0.0, Status: Up, Encapsulation: ATM CELL (VC Mode)
      Remote PE: 10.255.17.4, Negotiated control-word: Yes (Non-null)
      Incoming label: 100000, Outgoing label: 100000

user@PE1>  show route table l2circuit.0 detail

l2circuit.0: 2 destinations, 2 routes (2 active, 0 holddown, 0 hidden)
10.255.17.4:CtrlWord:9:32:Local/96 (1 entry, 1 announced)
         *L2CKT   Preference: 7
                Next hop: via so-0/2/0.0 weight 1, selected
                Label-switched-path PE1-PE2
                Protocol next hop: 10.255.17.4 Indirect next hop: 85135e8 367
                State: <Active Int>
                Local AS:    69 
                Age: 2:34 
                 Task: l2 circuit
                Announcement bits (1): 0-LDP 
                AS path: I
                VC Label 100000, MTU 0,  cell-bundle size 80

10.255.17.4:CtrlWord:9:32:Remote/96 (1 entry, 1 announced)
         *LDP     Preference: 9
                Next hop type: Discard
                State: <Active Int>
                Local AS:    69 
                Age: 28:11 
                 Task: LDP
                Announcement bits (1): 1-l2 circuit 
                AS path: I
                VC Label 100000, MTU 0,  cell-bundle size 80

user@PE1>  show interfaces at-0/1/0.0 extensive
  Logical interface at-0/1/0.0 (Index 66) (SNMP ifIndex 40) (Generation 4)
    Flags: Point-To-Point SNMP-Traps  Encapsulation: ATM-CCC-Cell-Relay
     L2 circuit cell bundle size: 10 , bundle timeout: 125 usec, timeout count: 0
    L2 circuit out-of-sequence count: 0
    Traffic statistics:
[...]

user@PE1>  show interfaces media at-0/1/0
Physical interface: at-0/1/0, Enabled, Physical link is Up
 Interface index: 154, SNMP ifIndex: 50
 Link-level type: ATM-CCC-Cell-Relay,  MTU: 4482, Clocking: Internal, SONET mode,
 L2 circuit mode: Cell, Speed: OC12, Loopback: None
[...]

user@PE1>  show ldp database l2circuit detail
Input label database, 10.255.17.2:0--10.255.17.4:0
    Label     Prefix
   100000     L2CKT CtrlWord ATM CELL (VC Mode) VC 32
              Cell bundle size: 80
              State: Active
              Age: 9:48

Output label database, 10.255.17.2:0--10.255.17.4:0
    Label     Prefix
   100000     L2CKT CtrlWord ATM CELL (VC Mode) VC 32
              Cell bundle size: 80
              State: Active
              Age: 9:48

This is what the operational command output looks like on Router PE1 if AAL5 mode is used:


user@PE1> show l2circuit connections 
Layer-2 Circuit Connections:

Legend for connection status (St)   
EI -- encapsulation invalid      NP -- interface not present
MM -- mtu mismatch               Dn -- down
EM -- encapsulation mismatch     VC-Dn -- Virtual circuit Down
CM -- control-word mismatch      Up -- operational
OL -- no outgoing label          XX -- unknown
NC -- intf encaps not CCC/TCC

Legend for interface status
Up -- operational
Dn -- down

Neighbor: 10.255.17.4
    Interface                 Type  St     Time last up          # Up trans
    at-1/2/0.0 (vc 32)        rmt   Up     Feb 18 18:00:00 2003           1
      Local interface: at-1/2/0.0, Status: Up, Encapsulation: ATM AAL5
      Remote PE: 10.255.17.4, Negotiated control-word: Yes (Non-null)
      Incoming label: 100016, Outgoing label: 100032

user@PE1> show interfaces media at-0/1/0
Physical interface: at-0/1/0, Enabled, Physical link is Up
 Interface index: 154, SNMP ifIndex: 50
 Link-level type: ATM-PVC, MTU: 4482, Clocking: Internal, SONET mode,
 L2 circuit mode: AAL5, Speed: OC12, Loopback: None, Payload scrambler: Enabled
[...]

user@PE1>  show interfaces at-1/2/0.0 extensive
  Logical interface at-1/2/0.0 (Index 68) (SNMP ifIndex 40) (Generation 38)
    Flags: Point-To-Point SNMP-Traps  Encapsulation: ATM-CCC-VCMUX
    L2 circuit out-of-sequence count: 0
    Traffic statistics:[...]

Example: Layer 2 Circuit Traffic Engineering over Multiple LSPs Configuration

Figure 76: Layer 2 Circuit Traffic Engineering Topology Diagram

Image g017157.gif

Figure 76 shows a network topology designed to traffic engineer different Layer 2 circuits over select LSPs. Across provider edge routers PE1 and PE2, an ATM AAL5 mode Layer 2 circuit connects customer edge routers CE1 and CE2, and a Frame Relay Layer 2 circuit connects routers CE3 and CE4. To maintain traffic separation, the ATM traffic is mapped onto LSP1 with a community named gold, and the Frame Relay traffic is mapped onto LSP2 with a community named silver. LSP1 takes the direct route between routers PE1 and PE2, while LSP2 travels from Router PE1 to PE2 through Router P0.

In addition to traffic engineering, you can send Layer 2 control information in the control word of a Layer 2 circuit. In this case, Frame Relay discard eligible (DE), forward explicit congestion notification (FECN), and backward explicit congestion notification (BECN) information is mapped into the control word. Likewise, ATM cell loss priority (CLP) and explicit forward congestion indicator (EFCI) information is mapped into the control word.

To traffic engineer Layer 2 circuits over multiple LSPs, you assign a set of Layer 2 circuits to a community and then apply a policy to send the community traffic over a desired LSP. To create communities, include the community community-name statement at the [edit policy-options] hierarchy level. To assign a Layer 2 circuit to a community, include the community community-name statement at the [edit protocols l2circuit neighbor neighbor-id interface interface-name] hierarchy level. To send community traffic over a specific LSP, include the community community-name statement at the [edit policy-options policy-statement policy-name term term-name from] hierarchy level and the install-next-hop lsp lsp-name statement at the [edit policy-options policy-statement policy-name term term-name then] hierarchy level.

On Router CE1, configure the ATM2 IQ interface at-0/0/1.32 to handle ATM AAL5 traffic:

Router CE1

[edit]
interfaces {
at-0/0/1 {
description "to PE1 at-1/1/0";
atm-options {
pic-type atm2; # Layer 2 circuits are compatible with
vpi 0; # ATM2 IQ interfaces.
}
unit 0 {
encapsulation atm-vc-mux; # Use ATM VC MUX encapsulation on the CE.
point-to-point;
vci 0.32;
family inet {
address 10.0.0.1/30;
}
}
}
}

On Router CE3, configure the SONET/SDH interface at so-0/0/1 to handle Frame Relay traffic:

Router CE3

[edit]
interfaces
so-0/0/1 {
description “to PE1 so-1/1/1”
encapsulation frame-relay; # Use Frame Relay encapsulation on the CE router.
unit 0 {
encapsulation frame-relay;
point-to-point;
dlci 512;
family inet {
address 10.10.0.1/30;
}
}
}

On Router PE1, configure the ATM2 IQ-based CE1-facing interface at-1/1/0 with ATM VC multiplexing CCC encapsulation on the logical interface. Also enable the corresponding Layer 2 circuit modes at the [edit chassis] hierarchy level. In this case, you must configure AAL5 mode on PIC 1 in FPC 1. Once you configure the ATM2 IQ-based Layer 2 circuit, the CLP and EFCI bits are mapped to the control word by default.

Next, configure the Frame Relay interface so-1/1/1 with Frame Relay CCC encapsulation on both the physical and logical interface. Map the DE, FECN, and BECN bits to the control word with the translate-fecn-and-becn and translate-discard-eligible statements at the [edit interfaces so-fpc/pic/port unit unit-number family ccc] hierarchy level.

Establish your Layer 2 circuits with configuration of the l2circuit statement at the [edit protocols] hierarchy level. Remember to include in your Layer 2 circuit configuration the IP address of your remote PE neighbor (usually the loopback address of the neighbor), the interfaces connected to the CE router, and a virtual circuit identifier for each VC. In this case, you will establish one VC for ATM AAL5 traffic and a second VC for Frame Relay traffic. Then, configure MPLS, LDP, and an IGP (such as OSPF) to enable signaling for your Layer 2 circuit. Two LSPs are established for the ATM and Frame Relay traffic: LSP1 for ATM traffic going directly to Router PE2 and LSP 2 for Frame Relay traffic going through Router P0 before going on to Router PE2.

Finally, configure a community for traffic separation for the ATM and Frame Relay Layer 2 circuits. Assign community goldto the ATM VC and community silver to the Frame Relay VC. Remember to give the communities numerical values and configure a routing policy to match the communities to specific LSPs. This policy is applied as an export policy for the forwarding table at the [edit routing-options] hierarchy level.

Router PE1

[edit]
chassis {
fpc 1 {
pic 1 {
atm-l2circuit-mode {
aal5; # This dedicates FPC 1 PIC 1 to AAL5 mode.
}
}
}
}
interfaces {
at-1/1/0 {
description "to CE1 at-0/0/2";
atm-options {
pic-type atm2; # Layer 2 circuits are compatible with
vpi 0; # ATM2 IQ interfaces.
}
unit 0 {
encapsulation atm-ccc-vc-mux; # CLP/EFCI bits are mapped to control word.
vci 0.32;
}
}
so-0/1/0 {
description "to P0 so-0/0/0";
unit 0 {
family inet {
address 192.168.27.17/30;
}
family mpls; # Include the MPLS family on core-facing interfaces.
}
}
so-1/1/0 {
description "to PE2 so-1/0/1";
unit 0 {
family inet {
address 192.168.27.10/30;
}
family mpls; # Include the MPLS family on core-facing interfaces.
}
}
so-1/1/1 {
description "to CE3 so-0/0/1";
dce;
encapsulation frame-relay-ccc;
unit 0 {
encapsulation frame-relay-ccc;
point-to-point;
dlci 512;
family ccc {
translate-fecn-and-becn; # Option to map FECN/BECN bits to control word.
translate-discard-eligible; # Option to map DE bit to control word.
}
}
}
lo0 {
unit 0 {
family inet {
address 10.255.17.2/32;
}
}
}
}
routing-options {
forwarding-table {
export layer2communities; # This applies communities to the Layer 2 circuits.
}
}
protocols {
mpls {
label-switched-path lsp1 { # ATM LSP 1 goes directly to PE2.
to 10.255.17.4;
primary direct;
}
label-switched-path lsp2 { # Frame Relay LSP 2 goes through P0.
to 10.255.17.4;
primary thruP0;
}
path direct {
192.168.27.9 strict;
}
path thruP0 {
192.168.27.18 strict;
192.168.27.25 strict;
}
interface so-0/0/1.0;
interface so-1/1/0.0;
}
ospf {
traffic-engineering;
area 0.0.0.0 {
interface so-0/0/1.0;
interface so-1/1/0.0;
interface lo0.0;
}
}
ldp { # LDP is required as the signaling protocol for Layer 2 circuits.
interface so-0/0/1.0;
interface so-1/1/0.0;
interface lo0.0;
}
l2circuit {
neighbor 10.255.17.4 {# This points to the loopback of the PE neighbor.
interface at-1/1/0.32 { # Here you include the local CE-facing interface.
virtual-circuit-id 1; # Be sure this ID matches the ID of your PE neighbor.
community gold;# Assigns the ATM Layer 2 circuit to the gold community.
}
}
neighbor 10.255.17.4 {# This points to the loopback of the PE neighbor.
interface so-1/1/1.512 { # Here you include the local CE-facing interface.
virtual-circuit-id 2; # Be sure this ID matches the ID of your PE neighbor.
community silver; # Assigns the Frame Relay Layer 2 circuit to silver.
}
}
}
}
policy-options {
policy-statement layer2communities { # Here you map the communities to LSPs.
term 10 {
from community gold; # Apply community gold to LSP 1.
then {
install-nexthop lsp lsp1;
accept;
}
term 20 {
from community silver; # Apply community silver to LSP 2.
then {
install-nexthop lsp lsp2;
accept;
}
community gold members 103:1; # Assign numerical value to community gold.
community silver members 103:2; # Assign numerical value to community silver.
}
}
}
}

On Router P0, configure LDP, MPLS, and OSPF on the interfaces connected to the PE routers. The core router provides the MPLS backbone needed to tunnel Layer 2 traffic from the ingress PR router to the egress PE router. Only LSP 2 for Frame Relay passes through Router P0.

Router P0

[edit]
interfaces {
so-1/1/1 {
description "to PE1 so-0/0/1";
unit 0 {
family inet {
address 192.168.27.18/30;
}
family mpls; # Include the MPLS family on core interfaces.
}
}
so-1/1/2 {
description "to PE2 so-0/1/1";
unit 0 {
family inet {
address 192.168.27.26/30;
}
family mpls; # Include the MPLS family on core interfaces.
}
}
lo0 {
unit 0 {
family inet {
address 10.255.17.3/32;
}
}
}
}
protocols {
mpls {
interface so-1/1/1.0;
interface so-1/1/2.0;
}
ospf {
traffic-engineering;
area 0.0.0.0 {
interface so-1/1/1.0;
interface so-1/1/2.0;
}
}
ldp {# LDP is required as the signaling protocol for Layer 2 circuits.
interface so-1/1/1.0;
interface so-1/1/2.0;
}
}

On Router PE2, complete the Layer 2 circuit by configuring statements to match those previously set on Router PE1.

Establish your Layer 2 circuits with configuration of the l2circuit statement at the [edit protocols] hierarchy level. Remember to include in your Layer 2 circuit configuration the IP address of your remote PE neighbor (usually the loopback address of the neighbor), the interfaces connected to the CE router, and a virtual circuit identifier for each VC. In this case, you will establish one VC for ATM AAL5 traffic and a second VC for Frame Relay traffic. Then, configure MPLS, LDP, and an IGP (such as OSPF) to enable signaling for your Layer 2 circuit. Two LSPs are established for the ATM and Frame Relay traffic: LSP1 for ATM traffic going directly to Router PE2 and LSP 2 for Frame Relay traffic going through Router P0 before going on to Router PE2.

Finally, configure a community for traffic separation for the ATM and Frame Relay Layer 2 circuits. The ATM VC has community gold and the Frame Relay VC has community silver. Remember to give the communities numerical values and configure a routing policy to match the communities to specific LSPs. This policy is applied as an export policy for the forwarding table at the [edit routing-options] hierarchy level.

Router PE2

[edit]
chassis {
fpc 1 {
pic 0 {
atm-l2circuit-mode {
aal5; # This dedicates FPC 1 PIC 0 to AAL5 mode.
}
}
}
}
interfaces {
at-1/0/1 {
description "to CE2 at-1/1/2";
atm-options {
pic-type atm2; # Layer 2 circuits are compatible with
vpi 0; # ATM2 IQ interfaces.
}
unit 0 {
encapsulation atm-ccc-vc-mux; # CLP and EFCI appear in the control word.
vci 0.32;
}
}
so-0/1/1 {
description "to P0 so-1/1/2";
unit 0 {
family inet {
address 192.168.27.25/30;
}
family mpls; # Include the MPLS family on core-facing interfaces.
}
}
so-1/0/1 {
description "to PE1 so-1/1/0";
unit 0 {
family inet {
address 192.168.27.9/30;
}
family mpls; # Include the MPLS family on core-facing interfaces.
}
}
so-1/1/1 {
description "to CE4 so-1/1/2";
dce;
encapsulation frame-relay-ccc;
unit 0 {
encapsulation frame-relay-ccc;
point-to-point;
dlci 512;
family ccc {
translate-fecn-and-becn; # Option to map FECN/BECN bits to control word.
translate-discard-eligible; # Option to map DE bit to control word.
}
}
}
lo0 {
unit 0 {
family inet {
address 10.255.17.4/32;
}
}
}
}
routing-options {
forwarding-table {
export layer2communities; # This maps communities to the Layer 2 circuits.
}
}
protocols {
mpls {
label-switched-path lsp1 { # ATM LSP 1 goes directly to Router PE2.
to 10.255.17.2;
primary direct;
}
label-switched-path lsp2 { # Frame Relay LSP 2 goes through Router P0.
to 10.255.17.2;
primary thruP0;
}
path direct {
192.168.27.10 strict;
}
path thruP0 {
192.168.27.26 strict;
192.168.27.17 strict;
}
interface so-0/1/1.0;
interface so-1/0/1.0;
}
ospf {
traffic-engineering;
area 0.0.0.0 {
interface so-0/1/1.0;
interface so-1/0/1.0;
interface lo0.0;
}
}
ldp { # LDP is required as the signaling protocol for Layer 2 circuits.
interface so-0/1/1.0;
interface so-1/0/1.0;
interface lo0.0;
}
l2circuit {
neighbor 10.255.17.2 {# This points to the loopback of the PE neighbor.
interface at-1/0/1.32 { # Here you include the local CE-facing interface.
virtual-circuit-id 1; # Be sure this ID matches the ID of your PE neighbor.
community gold;# Assigns the ATM Layer 2 circuit to the gold community.
}
}
neighbor 10.255.17.2 {# This points to the loopback of the PE neighbor.
interface so-1/1/1.512 { # Here you include the local CE-facing interface.
virtual-circuit-id 2; # Be sure this ID matches the ID of your PE neighbor.
community silver; # Assigns the Frame Relay Layer 2 circuit to silver.
}
}
}
}
policy-options {
policy-statement layer2communities { # Here you map communities to LSPs.
term 10 {
from community gold; # Apply community gold to LSP 1.
then {
install-nexthop lsp lsp1;
accept;
}
term 20 {
from community silver; # Apply community silver to LSP 2.
then {
install-nexthop lsp lsp2;
accept;
}
community gold members 103:1; # Assign numerical value to community gold.
community silver members 103:2; # Assign numerical value to community silver.
}
}
}
}

On Router CE2, configure the ATM2 IQ interfaces to handle ATM traffic. Interface at-1/0/1 handles AAL5 traffic.

Router CE2

[edit]
interfaces {
at-1/1/2 {
description "to PE2 at-1/0/1";
atm-options {
pic-type atm2; # Layer 2 circuits are compatible with
vpi 0; # ATM2 IQ interfaces.
}
unit 0 {
encapsulation atm-vc-mux; # Use ATM VC MUX encapsulation on the CE.
point-to-point;
vci 0.32;
family inet {
address 10.0.0.2/30;
}
}
}
}

On Router CE4, configure the SONET/SDH interface at so-1/1/2 to handle Frame Relay traffic:

Router CE3

[edit]
interfaces {
so-1/1/2 {
description “ to PE2 so-1/1/1”;
encapsulation frame-relay-ccc; # Use Frame Relay encapsulation on the CE.
unit 0 {
encapsulation frame-relay-ccc;
point-to-point;
dlci 512;
family inet {
address 10.10.0.2/30;
}
}
}
}

Verifying Your Work

To verify proper operation of traffic engineered Layer 2 circuits, use the following command:

show route table mpls.0 detail

On Router PE1, you can see that ATM traffic is part of the gold community that has a value of 103:1 and is associated with LSP 1. Likewise, Frame Relay traffic is part of the silver community that has a value of 103:2 and is associated with LSP 2:


user@PE1> show route table mpls.0 detail 
mpls.0: 2 destinations, 2 routes (2 active, 0 holddown, 0 hidden)
at-1/1/0.32  (1 entry, 1 announced)
          *L2CKT  Preference: 7
                  Next hop: 192.168.27.9 via so-1/1/0.0 weight 1, selected
                 Label-switched-path lsp1
                 Label operation: Push 100032 Offset: -4
                 Next hop: via so-0/0/1.0 weight 1
                 Label-switched-path lsp2
                 Label operation: Push 100032 Offset: -4
                 Protocol next hop: 10.255.17.4
                 Push 100032 Offset: -4
                  Indirect next hop: 8576bd0 300
                 State: <Active Int>
                 Age: 7:18
                 Task: Common L2 VC
                 Announcement bits (2): 0-KRT 1-Common L2 VC
                 AS path: I
                 Communities: 103:1 # This is the  gold  community.

so-1/1/1.512 (1 entry, 1 announced)
         *L2CKT  Preference: 7
                 Next hop: 192.168.27.9 via so-1/1/0.0 weight 1
                 Label-switched-path lsp1
                 Label operation: Push 100048 Offset: -4
                 Next hop: via so-0/0/1.0 weight 1, selected
                 Label-switched-path lsp2
                 Label operation: Push 100048 Offset: -4
                 Protocol next hop: 10.255.17.4
                 Push 100048 Offset: -4
                  Indirect next hop: 860f1f8 293
                 State: <Active Int>
                 Age: 5:15
                 Task: Common L2 VC
                 Announcement bits (2): 0-KRT 1-Common L2 VC
                 AS path: I
                 Communities: 103:2 # This is the  silver  community.

Example: APS for a Layer 2 Circuit Configuration

Figure 77: APS for a Layer 2 Circuit Topology Diagram

Image g017218.gif

Figure 77 shows that APS is configured on a PE router to protect a PE-CE link in a Layer 2 circuit. This example shows only the PE router configuration and assumes that you have preconfigured a full Layer 2 circuit topology. For more information about configuring Layer 2 circuits, see Configuring Layer 2 Circuits.

On Router PE1, configure ATM2 IQ interface at-0/0/1 as an APS protect circuit and ATM2 IQ interface at-1/3/1 as a working circuit. Also, configure the working circuit interface as the primary interface for your Layer 2 circuit and configure the protect circuit interface as the protected interface for your Layer 2 circuit.

Router PE1

[edit]
chassis {
fpc 0 {
pic 0 {
atm-l2circuit-mode {
cell; # This dedicates FPC 0 PIC 0 to cell-relay mode.
}
}
}
fpc 1 {
pic 3 {
atm-l2circuit-mode {
cell; # This dedicates FPC 1 PIC 3 to cell-relay mode.
}
}
}
}
interfaces {
at-0/0/1 {
description "To CE1 at-0/1/2";
encapsulation atm-ccc-cell-relay;
sonet-options {
aps {
protect-circuit TEST; # This interface is the APS protect circuit.
}
}
atm-options {
pic-type atm2;
promiscuous-mode;
}
unit 0 {
allow-any-vci;
}
}
at-1/3/1 {
description "To CE1 at-0/1/1";
encapsulation atm-ccc-cell-relay;
sonet-options {
aps {
working-circuit TEST; # This interface is the APS working circuit.
}
}
atm-options {
pic-type atm2;
promiscuous-mode;
}
unit 0 {
allow-any-vci;
}
}
}
protocols {
l2circuit {
neighbor 10.255.17.4 {
interface at-1/3/1.0 { # The Layer 2 circuit interface is the working circuit.
protect-interface at-0/0/1.0; # The protect-interface is the protect circuit.
virtual-circuit-id 100;
}
}
}
}

Verifying Your Work

To verify proper operation of APS for Layer 2 circuits, use the following command:

show l2circuit connections

After you configure the Layer 2 circuit and the APS working and protect circuits, you can see which APS circuit is active for the Layer 2 circuit with the show l2circuit connections command. The first local interface that is displayed is always the active circuit. If the second local interface field indicates Protect-Inactive, the working circuit is active, as shown in this output sample.


user@PE0> show l2circuit connections
Layer-2 Circuit Connections:

Legend for connection status (St)
EI -- encapsulation invalid      NP -- interface h/w not present
MM -- mtu mismatch               Dn -- down
EM -- encapsulation mismatch     VC-Dn -- Virtual circuit Down
CM -- control-word mismatch      Up -- operational
OL -- no outgoing label          XX -- unknown
NC -- intf encaps not CCC/TCC
CB -- rcvd cell-bundle size bad

Legend for interface status
Up -- operational
Dn -- down

Neighbor: 10.255.17.4
Interface                 Type  St     Time last up          # Up trans
 at-1/3/1.0(vc 100)        rmt   Up     Sep  3 17:48:25 2003           1
   Local interface: at-1/3/1.0, Status: Up, Encapsulation: ATM CELL (PORT Mode)
   Remote PE: 10.255.17.4, Negotiated control-word: Yes (Null)
   Incoming label: 100368, Outgoing label: 100112
   Local interface: at-0/0/1.0, Status: Dn, Encapsulation: ATM CELL (PORT Mode),
   Protect-Inactive

Conversely, if the first local interface is marked with the Protect-Active indicator, and the second local interface indicates Primary-Inactive, the protect circuit is active, as shown here:


user@PE0> show l2circuit connections 
Layer-2 Circuit Connections:

Legend for connection status (St)   
EI -- encapsulation invalid      NP -- interface h/w not present
MM -- mtu mismatch               Dn -- down
EM -- encapsulation mismatch     VC-Dn -- Virtual circuit Down
CM -- control-word mismatch      Up -- operational
OL -- no outgoing label          XX -- unknown
NC -- intf encaps not CCC/TCC
CB -- rcvd cell-bundle size bad

Legend for interface status  
Up -- operational            
Dn -- down                   

Neighbor: 10.255.17.4
 Interface                 Type  St     Time last up          # Up trans
 at-1/3/1.0(vc 100)        rmt   Up     Sep  3 17:51:06 2003           2
    Local interface: at-0/0/1.0, Status: Up,  Encapsulation: ATM CELL (PORT Mode),
    Protect-Active
   Remote PE: 10.255.17.4, Negotiated control-word: No
   Incoming label: 100368, Outgoing label: 100112
    Local interface: at-1/3/1.0, Status: Dn,  Encapsulation: ATM CELL (PORT Mode),
    Primary-Inactive
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