1. 1 T1X1.5/2002-046 Applications and Overview of Generic Framing Procedure (GFP) Mike Scholten (AMCC) e-mail: mscholten@amcc.com New ITU-T standard, G.7041 describes a Generic Framing Procedure (GFP) which may be used for efficiently mapping client signals into and transporting them over SONET/SDH or G.709 links. This presentation provides an overview of network applications which have driven the development of the GFP standard within T1X1.5 and ITU-T SG15. Applications are related to some of the features included in G.7041. This contribution is intended only to provide introductory background to G.7041 and does not make any proposals not already reflected in the standard. Previewing this contribution may help in understanding motivation behind and application of the capabilities included in G.7041.

2. 2 T1X1.5/2002-046 What is GFP? Emerging new standard for Data Encapsulation Accept any client, encapsulate in simple frame, transport over network Uses length/HEC frame delineation of variable length packets Allows multiple data streams to be transported over single path –Packet aggregation for router applications –Common encapsulation of different client data types (e.g. Ethernet, HDLC) Transparent Mapping supports LAN/SAN extension over WAN Extension headers support various network topologies –Null Extension Header for channelized Point-to-Point network –Linear Extension Header for Port Aggregation over Point-to-Point network –Ring Header for Resilient Packet Ring applications (removed to Living List)

3. 3 T1X1.5/2002-046 Basic GFP Frame Structure Core Header FCS (optional) Payload Area Length MSBLength LSBcHEC MSB Payload Payload Header FCS[31:24]FCS[23:16]FCS[15:8]FCS[7:0] Payload Type MSB Payload Type LSB tHEC MSB tHEC LSB Optional Extension Header cHEC LSB eHEC MSB eHEC LSB Ext Hdr Byte 1 Ext Hdr Byte 2 Ext Hdr Byte n

4. 4 T1X1.5/2002-046 Application: Packet Routing through Big Fat Pipes Packet Switch N x GbE SONET SDH Mapper SONET SDH Mapper SPI-4 SPI-3 Router-based WAN OC-48 STM-16 OC-192 STM-64 Packet Switch encodes/decodes 8B/10B and routes packets to appropriate SPI-n SONET/SDH Mapper encapsulates packets using PPP over GFP and maps them into concatenated payload (STS-48c/VC-4-16c or STS-192c/VC-4-64c) –Alternative to POS using PPP or EoS/LAPS using PPP –Avoids indeterminate bandwidth expansion due to HDLC transparency processing All packet switching in WAN handled by Layer 2 routing Single traffic type aggregated in edge switch & routers into big-fat-pipes going to desired hop in routing table Control info from 8B/10B encoding not preserved Relies on PPP for Link Configuration Edge Switch

5. 5 T1X1.5/2002-046 GFP Frame: PPP Packet Routing via GFP Core Header Payload Area Length MSBLength LSBcHEC MSB PPP Packet Payload Payload Header Payload Type MSB Payload Type LSB tHEC MSB tHEC LSB cHEC LSB FCS (optional) FCS[31:24]FCS[23:16]FCS[15:8]FCS[7:0]

6. 6 T1X1.5/2002-046 Application: Port Aggregation over Digital Wrapper Packet Switch N x GbE OTN Mapper OTN Mapper SPI-4 SPI-3 DWDM WAN OTU-1 OTU-2 Packet Switch encodes/decodes 8B/10B and routes packets to appropriate SPI-n OTN Mapper encapsulates packets using GFP with extension header and aggregates them into OPU-n payload. Single or multiple traffic types may be aggregated in edge switch onto single wavelength Control info from 8B/10B encoding not preserved Edge Switch

7. 7 T1X1.5/2002-046 GFP Frame: Packet Aggregation over OTU-n Core Header Payload Area Length MSBLength LSBcHEC MSB Packet Payload Payload Header Payload Type MSB Payload Type LSB tHEC MSB tHEC LSB Linear Extension Header cHEC LSB Channel ID Spare eHEC MSB eHEC LSB FCS (optional) FCS[31:24]FCS[23:16]FCS[15:8]FCS[7:0]

8. 8 T1X1.5/2002-046 Application: Resilient Packet Rings GbE MAC OC-m STM-n Packet Ring HDLC Proc. SONET SDH Mapper Framer Multiplex packet streams into single STS-Nc / VC-4-Xc Each packet encapsulated into GFP Frame Payload Type ID in payload header supports multi-service applications Allows spatial reuse (packet statistical muxing, rather than TDM at each node) GFP Extension headers support RPR Ring Node addressing Class of Service packet prioritization 802.17 RPR WG developed alternative to GFP extension Ring Header: RPR MAC generates/processes non-GFP ring header which is presented to GFP as part of payload Network Process. & Switch SPI-n 8B/10B Client Packet Stream Ring Node Ring Node Ring Node Ring Node Packet Add/Drop

9. 9 T1X1.5/2002-046 GFP Frame: RPR Using GFP Ring Header Core Header Payload Area Length MSBLength LSBcHEC MSB Packet Payload Payload Header Payload Type MSB Payload Type LSB tHEC MSB tHEC LSB DestPortSrcPort Spare DECoS TTL Dest MAC[47:40] Dest MAC[39:32] Dest MAC[31:24] Dest MAC[23:16] Dest MAC[15:8] Dest MAC[7:0] Src MAC[47:40] Src MAC[39:32] Src MAC[31:24] Src MAC[23:16] Src MAC[15:8] Src MAC[7:0] eHEC MSB eHEC LSB Ring Extension Header cHEC LSB FCS (optional) FCS[31:24]FCS[23:16]FCS[15:8]FCS[7:0] NOTE: GFP Ring Header removed to Living List; 802.17 RPR proposes to include ring header as part of GFP payload).

10. 10 T1X1.5/2002-046 Application: Extending LAN / SAN over WAN GbE FC 8B/10B Clients STS-m STM-n 8B/10B Client STS-m STM-n SONET / SDH Network GbE FC GbE FC GbE FC LAN / SAN 8B/10B Client GbE FC SONET SDH Mapper Framer SONET SDH Mapper Framer SONET SDH Mapper Framer Want to preserve individual 8B/10B block-coded channels, but…...Cannot fit two 1.25 Gb/s GbE channels into a single OC-48 / STM-16 Transport of single 1.25 Gb/s stream over OC-48 / STM-16 is excessively wasteful. Need to preserve control info (e.g. link configuration) for LAN extension, so… …Cannot just send data packets. Cannot just interleave two streams into single path and still expect SONET/SDH to deliver to different destinations.

11. 11 T1X1.5/2002-046 SAN Transport through Right-Sized Pipes using VC/GFP N x Fibre Chan, GbE, FICON, ESCON SONET SDH Mapper with VC SONET/SDH Switched WAN OC-48/STM-16 or OC-192/STM-64 Transparent Encapsulation / Decapsulation preserves Control Info Virtually-concatenated paths sized to fit individual client signals Client signals preserved intact through the network Signals routed by switching VC paths (STS-1/VC-3 or STS-3c/VC-4 switching) Mix of protocols may be carried, each in its own VC path Virtual Concatenation (VC) essential to compete against SAN over dark fiber SAN - WAN PHY 8B/10B Codec 8B/10B Codec Transparent Encapsulate / Extract Transparent Encapsulate / Extract

12. 12 T1X1.5/2002-046 Solution: VC + Transparent GFP Use Virtual Concatenation (VC) to partition SONET/SDH link into “right-sized” pipes “Right-sized” is smallest number of STS-3c/VC-4 or STS-1/VC-3 needed for client Compress 8B/10B client without losing control information Encapsulate compressed client signal into standard adaptation mechanism (GFP) T1X1.5/2000-046 (Jul-2000) established target VC-path sizes for various clients: –Gigabit Ethernet 1000 Mb/s; 1250 Mb/s 8B/10B block-coded fit into STS-3c-7v or VC-4-7v 2 STS-3c/VC-4 available after 2 GbE signals VC-mapped into OC-48/STM-16 –Fibre Channel and FICON 850 Mb/s; 1062.5 Mb/s 8B/10B block-coded fit into STS-3c-6v or VC-4-6v 4 STS-3c/VC-4 available after 2 Fibre Channel signals VC-mapped into OC-48/STM-16 –ESCON 160 Mb/s; 200 Mb/s 8B/10B block-coded fit into STS-1-4v or VC-3-4v 12 ESCON signals can be VC-mapped into OC-48/STM-16

13. 13 T1X1.5/2002-046 Solution: VC + Transparent GFP (cont.) T1X1.5/2001-04R1 (Jan-2001) established 64B/65B compression scheme: –Map 8-bit data directly into 64-bit block with pre-pended SyncBit = 0 –Map 12 control characters into 3-bit location + 4-bit control code

14. 14 T1X1.5/2002-046 Transparent GFP Mapping (cont.) 12 8B/10B “Special Characters” remapped to 4-bit codes as shown 10B Violations mapped as “10B_ERR” (RD errs, unrecognized 10B codes) Rate adapt by inserting “65B_PAD” code

15. 15 T1X1.5/2002-046 GFP Encapsulation of N x [536,520] Superblocks Encapsulate N x [536,520] superblocks into standard GFP Frames Relocate leading “sync bits” of 8 x 65B blocks to end of 8 x 64-bit blocks Compute & append CRC-16 after 8 x 65B blocks to create [536,520] superblock [536,520] superblock maintains byte alignment Choose N to fit available bandwidth of selected virtually-concatenated path Scramble Payload Area using self-synchronous x 43 +1 scrambler 4.Pre-pend with GFP core & payload headers. Leading Bit 8 byte block 8 x 65B blocks = 520 bits 1.Group 8 x 65B blocks 2.Rearrange Leading Bits at end 3. Generate & append CRC-16 checkbits to form [536,520] superblock. Payload Header (4 bytes) Core Header (4 bytes) N x [536,520] Superblocks Optional FCS (4 bytes) 6.Form GFP frames with N x [536,520] superblocks. 5.Scramble payload header & payload with x 43 +1. (Core header not scrambled.)

16. 16 T1X1.5/2002-046 Handling 8B/10B Disparity Client Source Transp. GFP Mapper Framer Transp. GFP De-map Client Sink 8B/10B Client STS-m STM-n 8B/10B Client STS-m STM-n SONET / SDH Network 1.25Gb/s GbE, 1.0625Gb/s FC or FICON, 200Mb/s ESCON Client IngressClient TransportClient Egress Ingress Code Violations Detected: Invalid Codewords Running Disparity Errors Map 10B_ERR into GFP Frame. Egress Codeword Generation: Generate correct disparity. Prevent disparity error propagation across data packets. Handle received 10B_ERR.

17. 17 T1X1.5/2002-046 Signal Fail Handling in Transparent Mapping Client Source Transp. GFP Mapper Framer Transp. GFP De-map Client Sink 8B/10B Client STS-m STM-n 8B/10B Client STS-m STM-n SONET / SDH Network 1.25Gb/s GbE, 1.0625Gb/s FC or FICON, 200Mb/s ESCON Client IngressClient TransportClient Egress Signal Fail Conditions on Ingress: Protocol-specific Client Signal Failures Loss of Signal  GFP_CSF Loss of Synchronization  GFP_CSF Signal Fail Handling on Egress: Locally detected Signal Fail Section / RS defects (LOS, OOF/LOF, RS-TIM)  10B_ERRs Line / MS defects (AIS-L)  10B_ERRs Path defects (LOP-P, PLM, UNEQ, MS-TIM)  10B_ERRs VC-Path defects (dLOM, dSQM, dLOA)  10B_ERRs GFP Frame Sync Loss  10B_ERRs Received Signal Fail conditions GFP_CSF  10B_ERRs Handling of non-failure errors Errored 8 x 65B Superblock  8 x 8 10B_ERR chars Non-decodable 65B Block  8 x 10B_ERR chars Definitions: GFP_CSF = GFP Client Mgt Frame with Client Signal Fail Indication 10B_ERRs = stream of consecutive 10B_ERR codewords

18. 18 T1X1.5/2002-046 Clocking Options for Egress Client Signals Client Source Transp. GFP Mapper Framer Transp. GFP De-map Client Sink 8B/10B Client STS-m STM-n 8B/10B Client STS-m STM-n SONET / SDH Network 1.25Gb/s GbE, 1.0625Gb/s FC or FICON, 200Mb/s ESCON Client IngressClient TransportClient Egress Egress Clock Options: Recover Client clock from transported GFP-mapped client signal; or Rate adapt extracted client to locally derived client reference clock.

19. 19 T1X1.5/2002-046 Frame-Mapped GFP vs. Transparent GFP

20. 20 T1X1.5/2002-046 GFP Overview Summary Various GFP Applications have been described and illustrated –Packet routing –Port aggregation over SONET/SDH or OTN using Linear Extension Headers –Resilient Packet Ring applications using Ring Extension Headers –Transparent Transport of 8B/10B clients Basic GFP Frame Structure has been described and shown –Length/cHEC frame delineation, similar to ATM cell delineation. –Payload Headers ID encapsulated payload & encapsulation options Presence or absence of optional FCS Presence and type or absence of extension header Payload type allows for mixing data types in a single SONET/SDH or OTN path –Extension headers support various network topologies Null Extension Header for channelized Point-to-Point network Linear Extension Header for Port Aggregation over Point-to-Point network Ring Header for Resilient Packet Ring applications LAN/SAN extension over WAN using Transparent Mapping described and shown –64B/65B re-coding preserves data & control for “transparent” transport –[536,520] superblocks provide error detection / correction over relatively small blocks –Supports efficient transport of full-rate 8B/10B clients over smallest paths Foundation laid for more easily understanding ITU-T G.7041 GFP Standard