ESM on PXC-based PW ports

This section provides an example to configure PW port based capture SAP that is used in ESM. For more information about PXC Based PW ports, see the 7450 ESS, 7750 SR, 7950 XRS, and VSR Layer 2 Services and EVPN Guide: VLL, VPLS, PBB, and EVPN.

PXC Configuration

The following is a PXC configuration example:

configure
   port-xc
      pxc 1 create
         port 1/1/1 
         no shutdown
      pxc 2 create 
         port 2/1/1 
         no shutdown

With this configuration, ports 1/1/1 and 2/1/1 are auto-provisioned in hybrid mode operating as individual loopback ports. The SR OS system automatically creates a pair of sub-ports per PXC. Those sub-ports are by default in shutdown state:

configure   
   port pxc-1.a
      shutdown
   port pxc-1.b 
      shutdown

   port pxc-2.a
      shutdown 
   port pxc-2.a
      shutdown

For redundancy purposes or increased bandwidth, the PXC sub-ports are aggregated in a LAG:

configure
    lag 1 create
        port pxc-1.a
        port pxc-2.a
    lag 2 create
        port pxc-1.b
        port pxc-2.b

FPE Configuration

A PW port is associated with PXC by an FPE configuration. FPE configuration facilitates creation of an internal tunnel over PXC. This tunnel is used to map the external PW to the PW port. For more information about FPE, see 7450 ESS, 7750 SR, 7950 XRS, and VSR Interface Configuration Guide.

The following is an FPE configuration example:

configure 
    fwd-path-ext 
        fpe 1 create
            path xc-a lag-1 xc-b lag-2
            pw-port   

The association between xc-a/b (cross-connects) and LAG IDs is performed arbitrarily by the operator. For example, it can associate xc-a with lag-id 2 (which includes PXC sub-ports on the .b side) and xc-b with lag-id 1 (which includes PXC sub-ports on the .a side). However, the FPE always assigns the .a side of the pxc sub-ports to the transit side of the cross-connect, while the .b side of the pxc subport is assigned to the termination side of the cross-connect. See the PXC Based PW port sections in the 7450 ESS, 7750 SR, 7950 XRS, and VSR Layer 2 Services and EVPN Guide: VLL, VPLS, PBB, and EVPN, for further information about transit/termination side of the cross-connect.

PW port creation

The PW port must be explicitly created in the SR OS, before mapping between PW and PW port can be performed.

pw-port 100 create
    encap-type qinq

SDP creation for the external PW

The following displays an SDP configuration for the external PW.

configure
    service
        sdp 1 create
            signaling tldp
            far-end 10.1.1.1

The PW can be static or dynamically signaled, with MPLS or GRE transport.

Mapping between the external PW and the PW port

The stitching of the external PW and PW port is configured through an Epipe in vc-switching mode.

configure
    service
        epipe 10 customer 1 vc-switching create
            spoke-sdp 1:100 create
            pw-port 100 fpe 1 

Capture PW-SAP creation

PW-SAPs can be configured as capture SAPs. In this example, a capture PW-SAP with s-tag 3 is created on the pw-port 100.

configure
    service vpls 2 create
        sap pw-port-100:3.* capture-sap create

From here, ESM functionality is applied to the PW-SAP in the same manner as on any other regular SAP.

Cross-connecting SAPs to PW ports

In addition to PW termination, a PW port can become a terminating point for a regular SAP. For example:

configure
    service
        epipe 10 customer 1 vc-switching create
            sap 1/1/1:10.* create
            pw-port 100 fpe 1

In this example, the outer VLAN tag 10 in the payload is removed on ingress and the payload is delivered to the PW port where it can be mapped to a capture PW-SAP. This scenario allows traffic distribution from a single I/O port to different EMS termination points (anchor line cards) based on outer VLANs.