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802.1ah Ethernet PW. draft-martini-pwe3-802.1ah-pw-03.txt Ali Sajassi July 29, 2008. Authors. Luca Martini Ali Sajassi. History. Rev. 00 Feb 07 Rev 01 July 07 Rev 02 Feb 08 Rev 03 July 08. Changes from Rev. 02. None. What is it ?.
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802.1ah Ethernet PW draft-martini-pwe3-802.1ah-pw-03.txt Ali Sajassi July 29, 2008
Authors • Luca Martini • Ali Sajassi
History • Rev. 00 Feb 07 • Rev 01 July 07 • Rev 02 Feb 08 • Rev 03 July 08
Changes from Rev. 02 • None
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
u-PE w/ IB-BEB u-PE w/ IB-BEB PB PB BCB BCB PB PB PE PE P P CE P P PE Where it is needed ? • 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 MPLS Core Customer Network (802.1Q) Customer Equipment Access Network (802.1ah) Access Network (MPLS) IB- BEB BCB IB- BEB
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.
VPLS PE Model as Defined in L2VPN Frwk (copied from bridge-interop preso Nov 04) Pseudowires PE LAN Emulation module VPLS FWDR VPLS FWDR Bridge Module VPLS FWDR Virtual Bridge Port (multiplexer) Physical port Toward CEs
VPLS as LAN (VLAN) Emulation (copied from bridge-interop preso Nov 04) VPLS as (V)LAN Emulation
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 !!
Next Step • Solicit comments on the mailing list