Alcatel-Lucent 7750 SR - Atm;Frame Relay PVC Access and Termination on a VPLS Service; Figure 89: Atm;Frame Relay PVC Access and Termination on a VPLS Example

Virtual Private LAN Services
7750 SR OS Services Guide Page 569
ATM/Frame Relay PVC Access and Termination on a VPLS Service
Figure 89: ATM/Frame Relay PVC Access and Termination on a VPLS Example
The application is depicted in above provides access to a VPLS service to Frame Relay and 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 (for example, 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-
VPLS
VPLS
VPLS
ATM
IP/MPLS
IP/IPX
RFC2684
B-PDU
AAL5 ATM
IP/IPX
Ethernet (VLAN)
IP/IPX
Ethernet (VLAN)
EthoMPLS
MPLS
POS/GigE
IP/IPX
RFC2684/RFC2427
B-PDU
AAL5 ATM
FR
CE1
CE2
CE3
PE 1
PE 3
PE 2
CE4
ATM1
ATM2
APS Protected
Links
7750 SR
7750 SR
7750 SR
ATM3
OSSG060
ATM/FR
UNI
PVC/SPVC
Ethernet-MPLS
Network IWF
ATM/FR
UNI
Ethernet
(VLAN) UNI
Ethernet
(VLAN) UNI
Ethernet
PW
Ethernet
PW