1. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 1 draft-martini-pwe3-802.1ah-pw-03.txt Ali Sajassi July 29, 2008 802.1ah Ethernet PW

2. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 2 Authors  Luca Martini  Ali Sajassi

3. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 3 History  Rev. 00 Feb 07  Rev 01 July 07  Rev 02 Feb 08  Rev 03 July 08

4. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 4 Changes from Rev. 02  None

5. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 5 What is it ?  Just like tagged PW where a VLAN tag is carried as service delimiter (for PSN) in the PW, this new PW type allows for an I-tag to be carried as service delimiter (for PSN) in the PW.  It is needed for certain scenarios  In some other scenarios raw-mode PW can be used

6. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 6 Where it is needed ? P P MPLS Core IB- BEB BCBBCB CECE BCBBCB PE BCBBCB P P P P P P Access Network (MPLS) PBPB PBPB u-PE w/ IB-BEB PBPB PBPB Customer Network (802.1Q) Customer Equipment Access Network (802.1ah) - PE devices are connected to BCB (not BEB) - different access networks use different I-SID domains - thus a given single PE needs to translate remote I-SID value into its local I-SID

7. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 7 Why is it needed ?  Based on RFC 4664 & bridge-interop draft, the PE is modeled as having a bridge module connected via Emulated LAN interface to an “Emulated LAN”  Since this is a single interface, for any given I-SID, only a single I-SID translation can be performed  If for a given I-SID, multiple translations are needed (one per remote PE), then such translation should be performed by PW termination/NSP before coming to the forwarder.

8. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 8 Virtual Bridge Port (multiplexer) VPLS PE Model as Defined in L2VPN Frwk (copied from bridge-interop preso Nov 04) VPLS FWDR VPLS FWDR VPLS FWDR Pseudowires PE LAN Emulation module Physical port Toward CEs Bridge Module

9. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 9 VPLS as LAN (VLAN) Emulation (copied from bridge-interop preso Nov 04) VPLS as (V)LAN Emulation

10. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 10 When it is not needed ?  When the bridge module performs I-SID translation (e.g., connected to B-BEBs), then it can do without performing translation over the PW.  In such case, a raw-mode PW can be used – there is no need to come up with a new type of PW  Since the action of tag-translation, insertion, removal is local and asymmetric, there is no need to exchange such info via LDP signaling !! – thus no need for new generic or brand-name PW !!

11. © 2006 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 11 Next Step  Solicit comments on the mailing list