Atm/Frame Relay Pvc Access And Termination On A Vpls Service - Alcatel-Lucent 7750 SR OS Service Manual

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Configuring a VPLS Service with CLI

ATM/Frame Relay PVC Access and Termination on a VPLS Service

RFC2684/RFC2427

Figure 5: ATM/Frame Relay PVC Access and Termination on a VPLS Example

The application is depicted in

ATM users connected either directly or through an ATM access network to a 7750 PE node. The

7750 SR supports a Frame Relay or an ATM VC-delimited Service Access Point (SAP)

terminating on a VPLS service.

RFC 2427-encapsulated or RFC 2684-encapsulated untagged Ethernet/802.3 frames (with or

without Frame Check Sequence (FCS)) or BPDUs from a customer's bridge device are received

on a given SAP over an ATM or Frame Relay interface on the 7750 SR. The Frame Relay or ATM-

related encapsulation is stripped and the frames (without FCS) are forwarded towards destination

SAPs either locally, or using SDPs associated with the VPLS service (as dictated by destination

MAC address VPLS processing). In the egress direction, the received untagged frames are

encapsulated into RFC 2427 or RFC 2684 (no Q-tags are added, no FCS in the forwarded frame)

and sent over ATM or a FR VC towards the customer CPE.

When AAL5 RFC2427/2684 encapsulated tagged frames are received from the customer's bridge

on an FR/ATM SAP, the tags are transparent and the frames are processed as described above with

the exception that the frames forwarded towards the destination(s) will have the received tags

preserved. Similarly in the egress direction, the received tagged Ethernet frames are encapsulated

as is (i.e. Q-tags are again transparent and preserved) into RFC 2427/2684 and sent over the FR/

ATM PVC towards the customer CPE. Note that since the tagging is transparent, the 7750 SR

performs unqualified MAC learning (i.e., MAC addresses are learned without reference to VLANs

they are associated with). Because of that, MAC addresses used must be unique across all the

VLANs used by the customer for a given VPLS service instance. If a customer wants a per-VLAN

separation, then the VLAN traffic that needs to be separated must come on different VCs (different

SAPs) associated with different VPLS service instances.

APS Protected

provides access to a VPLS service to Frame Relay and

7750 SR OS Services Guide

Ethernet-MPLS

Ethernet (VLAN)