1 / 24

SPVC Service Spanning ATM & PWE3/PSN George Swallow swallow@cisco

SPVC Service Spanning ATM & PWE3/PSN George Swallow swallow@cisco.com. The problem. Customer Site. Customer Site. Customer Site. Customer Site. PE. MPLS. ATM. Customer Site. Customer Site. Requirements. SPVC setup across ATM and PSN Recovery

oriole
Télécharger la présentation

SPVC Service Spanning ATM & PWE3/PSN George Swallow swallow@cisco

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. SPVC ServiceSpanning ATM & PWE3/PSNGeorge Swallowswallow@cisco.com

  2. The problem Customer Site Customer Site Customer Site Customer Site PE MPLS ATM Customer Site Customer Site

  3. Requirements • SPVC setup across ATM and PSN • Recovery • No per VC / VP configuration at ATM/PSN boundary • rules out simple splicing • Flexibility in where re-assembly occurs • Minimal or no change to ATM software • Simple solution needed soon

  4. Terminology Customer Site Customer Site ME1 AE1 ATM MPLS PME1 PAE1 AE2 ME2 Key: P - Provider A - ATM M - MPLS E - Edge

  5. Solution Elements / Issues • MPLS / ATM Interface • Addressing • Circuit Identification • Recovery

  6. PWE Identifiers • Two Identifiers for circuit • SAI - Source Attachment Identifier • TAI - Target Attachment Identifier • Structure of SAI, TAI • AGI - Attachment Group Identifier • AII - Attachment Individual Identifier • (In role of source or target AII takes on the name SAII or TAII respectively)

  7. Mismatched Identifiers • ATM • Called Party ATM Address -> Remote Switch & Interface • SPVC IE -> DLCI or VPI/VCI • PWE3 • IP Address -> Remote Switch • TAI -> Interface & DLCI or VPI/VCI

  8. 35 00 02 00 00 00 00 00 00 00 IPv4 Port IDP HO-DSP AFI ICP ESI SEL NSAP Format

  9. Mapping Identifiers SPVC Called Party Address SEL IDP HO-DSP ESI DLCI ESI DLCI IP Address Target for LDP FEC TAII

  10. Mapping Identifiers (2) • SPVC IE carries DLCI or VPI / VCI • Two special AGIs are defined to indicate format of the TAII • AGIfr -> <ESI><DLCI> • AGIatm -> <ESI><VPI><VCI> • No further semantics implied • VPI / VCI in SPVC IE does not imply ATM

  11. MPLS / ATM Interface • Interface between ATM and MPLS is AINI or UNI / IISP • MPLS network is modeled as a Multi-homed ATM Host (with lots of addresses) • All AEs advertise the same single NSAP prefix for the MPLS Network • Prefix ::= <IDP for IPv4><IP Net Prefix>

  12. ATM / FR Interworking, FRF5, FRF 8.1 configured at PAE and/or PME Pseudo-wire encapsulation selected on basis of Re-assembly Re-assembly occurs at ME based on presence of AAL5 IE or FD bits Re-assembly & ATM / FR IWF Customer Site Customer Site ME1 AE1 Label Mapping PNNI / Q.2931 UNI ATM MPLS PME1 PAE1 AE2 ME2

  13. Qos configured at PAE and PME Forward & Reverse ATM QoS carried in ATM Signaling Reverse MPLS QoS configured at PME because LDP is uniditectional Forward MPLS QoS inferred from ATM Signaling Quality of Service (QoS) Customer Site Customer Site ME1 AE1 PNNI / Q.2931 UNI ATM MPLS PME1 PAE1 AE2 ME2

  14. Configuration • PMEs: AGIs and (T)AII (note AII indicates both interface and DLCI or VPI/VCI) • PAEs: NSAP and DLCI or VPI/VCI • MEs configured with special AGIs that indicate the further structure of the AII

  15. SPVC Setup • Call is originated from the ATM side • Called Party address • NSAP encoded IP loopback address for MPE + • Interface encoded in ESI • SPVC IE carries DLCI or VPI / VCI

  16. ATM Setup: PAE to ME • PAE uses normal procedures • PNNI determines path to ATM address, selecting an AE • Setup message formatted and sent • Call is routed through a UNI to a ME • ME terminates ATM call

  17. ATM Setup: PAE to ME Customer Site Customer Site ME1 AE1 PNNI / Q.2931 UNI ATM MPLS PME1 PAE1 AE2 ME2 PAE1 uses normal FR SPVC setup

  18. MPLS Setup: ME to MPE • LDP session created to MPE loopback (if not already setup) • TAII created by formatting ESI + DLCI or ESI + VPI/VCI • SAII mapped based on incoming Port & VPI/VCI • Signals L2VPN FEC with AGI + TAII

  19. MPLS Setup: MPE to ME Customer Site Customer Site ME1 AE1 Label Mapping Label Mapping ATM MPLS PME1 PAE1 AE2 ME2 ME1 sends a label for FEC <SAI><TAI> PME1 responds with a label for FEC with values of SAI and TAI reversed

  20. SPVC Setup Completion • PME uses TAII to identify interface and DLCI or VPI/VCI (could be literal or symbolic) • PME responds with reverse setup • ME then completes the ATM call

  21. ATM Setup: ME to PAE Customer Site Customer Site ME1 AE1 Q.2931 / PNNI ATM MPLS PME1 PAE1 AE2 ME2 ME1 sends Connect message to PAE1

  22. Recovery Customer Site Customer Site ME1 AE1 Clear X PTSP LABEL Withdraw ATM Connect Label Mapping PME1 PAE1 Setup MPLS AE2 ME2 PTSP Removes NSAP prefix for MPLS network

  23. Conclusions • Wide deployment of PWE3 will not happen without a tractable transition plan • Proposal places all functions within boxes in PSN (don’t expect ATM vendors to be highly motivated to assist in the transition) • So far ATM / PWE proposals from other organizations has been complex • Needs to be done by the IETF to keep it simple

  24. Thank You

More Related