draft-jounay-pwe3-dynamic-pw-update-00.txt IETF 70 PWE3 Working Group Vancouver, December 2007 F. Jounay, P. Niger, France Telecom Y. Stein, RAD Data Communications H. Shah, Ciena Corp

Problem Statement Use Case identified : Mobile Backhauling IETF70, December 2007 Problem Statement Use Case identified : Mobile Backhauling CESoPSN PW used to carry the 2G traffic (mainly voice traffic) CESoPSN specifications Inherent trade-off between bandwidth consumption and latency => The Operator must setup CESoPSN PW so as to carefully match the PW capacity to the actual payload. Problem Statement when upgrading the network (e.g.: introduction of new cells, new services…) the capacity of particular PWs needs to grow without interrupting ongoing voice services used by numerous customers. Although interface parameter update will generally be a rare event for most applications, it is still highly recommended not to negatively impact customer services. Solutions so far proposed to increase a CESoPSN PW capacity Teardown the existing PW, and setup a new one with the new appropriate parameters Cons: service disruption Setup an additional PW for the specific additional bandwidth Cons: as many pw as updates required IETF70, December 2007

Possible solutions Scenario1 "New PW" IETF70, December 2007 Possible solutions Scenario1 "New PW" Setting up a new PW in parallel with the updated interface parameters New FEC => new PW label Static switching from the old to the new PW Scenario2 "PW Update" Remaining the existing FEC New Label Mapping message including the new interface parameters  Dynamic PW Update IETF70, December 2007

PW Update Overview 2 options for the solution description IETF70, December 2007 PW Update Overview 2 options for the solution description Definition of a specific mechanism to allow on-the-fly updating of CESoPSN PW capacity, i.e. while avoiding service interruption Definition of a generic mechanism for PW parameters Update The draft defines the generic solution and addresses the CESoPSN use case Potential other use cases PW interface parameters of other PW Type PW Label Update (may be required for OAM purpose, Step from static to dynamic PW (Status negotiation…) setup)… … IETF70, December 2007

CESoPSN Update Solution Overview IETF70, December 2007 CESoPSN Update Solution Overview Need a way to update the PW interface parameters without service disruption Requirement Signaling the update in the control plane Synchronizing the update in the data plane (The Length field of CESoPSN PW packet is not sufficient to correctly restitute the traffic over the AC, see next slides) Proposal Control plane: new LDP mapping message with a PW Update sub-TLV To be included to the LDP Label Mapping initiated to update the PW To indicate the update behavior of the new LDP mapping Backward compatibility: otherwise the new LDP message is usually dropped since an existing label has already been assigned to this FEC Data plane: in-band detection based on the new label assignment Required to allow the egress PE to forward over the AC the received traffic with the new format IETF70, December 2007

CESoPSN Interface Parameters Extracted from [PW TDM CTRL] Configured by the operator N: Number of DS0 channels in the corresponding attachment circuit that must be retrieved from the E1 frames and must be transported over the CESoPSN PW. D: Packetization latency in millisecond (application-related) Derived/calculated B: Number of frames to be encapsulated per PW packet derived from the Latency B = 8*D (8 E1 frames per second) P: Total Payload (Bytes) per PW packet P: B*N Signaled (PW setup) N: The interface parameter CEP/TDM Bit-Rate (0x07) is defined for all kinds of structure-aware emulation P: The interface parameter CEP/TDM Payload Bytes (0x04) is defined for a set of TDM PW types including SAToP, CESoPSN PWs 'update' operation encompass change in configuration ensued by update signaling. IETF70, December 2007

CESoPSN Interface Parameters IETF70, December 2007 CESoPSN Interface Parameters P = B*N  N is known as it has been advertised  B = P / N LDP Label Mapping [FEC129, Label, int.par.(N, P)] PE1 PW1 AI1 AI2 PE2 ce1 ce2 N ?... PW1 P = B (3) x N E1 frame Payload N bytes E1 frame Payload N bytes IETF70, December 2007

The PW Update sub-TLV Definition of a new LDP TLV TYPE (e.g. 0x096D) 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + Generalized ID FEC + | PW Update TLV | | Interface Parameters | | " | |0|0| Generic Label (0x0200) | Length | | Label | |1|0| PW Status (0x096A) | Length | | Status Code | 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1|0| PW Update Type (0x096D)| Length | | Update Code | Update code e.g., Interface Parameters PW label Keeping the existing LDP TLV TYPE (0x096B) For the int. parameters values IETF70, December 2007

Procedure (e.g. cesopsn PW update) IETF70, December 2007 Procedure (e.g. cesopsn PW update) Increase the PW capacity Step 1: update the PW capacity following the proposal Step 2 : update the CE to allow it to transport more payload per E1 frames Decrease the PW capacity Step 1 : update the CE to allow it to transport less payload per E1 frames Step 2: update the PW capacity following the proposal Remark: e.g. the cesopsn PW encapsulates non used-timeslots between the step 1 and step 2. IETF70, December 2007

PW Update Illustration for cesopsn PW IETF70, December 2007 PW Update Illustration for cesopsn PW Initial config (N=15, P = D(1ms)*8*15= 120) PE1 PW1 AI1 AI2 PE2 ce1 ce2 LDP Label Mapping ([SAI1, SAI2], L1, (P=120, N=15)] LDP Label Mapping ([SAI2, SAI1], L2, (P=120, N=15)] L2 8 X L1 IETF70, December 2007

PW Update Illustration for cesopsn PW IETF70, December 2007 PW Update Illustration for cesopsn PW Update config (N=20, P = D(1ms)*8*20= 160) PE1 PW1 AI1 AI2 PE2 ce1 ce2 LDP Label Mapping ([SAI1, SAI2], L10, PW Update (L, iP), (N=20, P=160)] LDP Label Mapping ([SAI2, SAI1], L20, PW Update (L, iP), (N=20, P=160)] L2 L20 L1 L10 Non Used-timeslots to be encapsulated during the transition step IETF70, December 2007

Next Steps Add a section describing the PW Label removal from the LFIB IETF70, December 2007 Next Steps Add a section describing the PW Label removal from the LFIB Describe the MS-PW approach Soliciting comments IETF70, December 2007