Principles of Circuit Switched Networks. John S Graham Indiana University

Transcription

1 Principles of Circuit Switched Networks John S Graham Indiana University

2 Syllabus Review of Current OpAcal Technologies What s a circuit; what s a cross connect? How are SONET/SDH and OTN different? How are packet and circuit switching merging? Principles of OA&M in OpAcal Networks Why s my router interface reporang only B3 errors? Abandon BFD All Ye Who Enter Here! DiagnosAc Tools in OpAcal Networks The Joy of Loops TAPs

3 Hybrid Packet/OpAcal Networks p a c k e t Ethernet IP G LAN PHY G WAN PHY G PHY HDLC o p = c a l SONET [OC92] Op=cal Transport Network [OTU2] GFP (G.74) DWDM

4 What is a Circuit? /2 A circuit connects two endpoints by means of a series of alterna=ng fibers and crossconnects Terminal Regenerators Terminal Tributary Interface Line Interface

5 What is a Circuit? 2/2 ADM Connected in a Ring Tributary Interface Line Interface

6 Synchronous = Flexible MulAplexing N OC 48 Line (West North) OC 48 Line (North East) W E OC 48 Line (South West) S OC 48 Line (East South)

7 OpAcal Transport Network (OTN) Client OpAcal Payload Unit (OPU k) 4G OpAcal Data Unit (ODU k) OpAcal Transport Unit (OTU k) OTU3 ODU3 OPU3 4 G OTU2 ODU2 OPU G OTU ODU OPU 2 G ODU OPU

8 SONET/SDH versus OTN. Timing SONET/SDH. Internally synchronous 2. Not synchronous with clients 2. Flexible mulaplexing 3. Fixed frame rate 4. Can be very bandwidth efficient 5. No error correcaon OTN (G.79). Timing. Internally asynchronous 2. Synchronous with clients 2. Enforced mulaplexing scheme 3. Fixed frame size 4. Possibility of bandwidth inefficiencies 5. Coding gains from forward error correcaon

9 Of Frames and Payloads Ethernet or HDLC Frame consists of indivisible overhead, payload and checksum SONET/SDH Frame consists of overhead and a container Payload is a separate structure with its own overhead Payload overlaps two successive frames Pointers required to adapt payload received from an alien SONET line OTN Has characterisacs of both the above

10 Single Payload FloaAng Within SPE

11 What Does A Cross Connect Represent? SONET Transfer payload (with overhead) between SONET lines OTN Moves an ODU j between different OTU k (k >= j) For 3R operaaon on a concatenated ODU k For switching ODU j within channelized ODU k OCh cross connect moves an OTU k frame from one ITU wavelength to another Packet OpAcal Switching VLAN tags at the packet/opacal interface

12 Packet OpAcal Convergence OpAcal provides to packet: Economies of scale and mulaplexing Tried and true OA&M IP rouang concepts from packet switching: End to end automated provisioning Replace inflexible SONET and WDM rings with mesh architectures ProtecAon based on available instead of reserved bandwidth Traffic classificaaon

13 GFP: The Great Arbitrator Adapted from: IEEE CommunicaCons Magazine, May 22

14 Tasks Performed by GFP Major Client frame delineaaon Client payload mapping Client to carrier rate adaptaaon Minor Limited OA&M (Link Loss Forwarding) OpAonal client frame mulaplexing

15 (Undesirable) AlternaAves to GFP ATM Cell overhead causes % bandwidth inflaaon AdaptaAon funcaons needlessly complex Packet over SONET (POS) Byte stuffing causes non determinisac bandwidth inflaaon Expensive router hardware

16 SONET Layers ADM2 DXC R2 R ADM SecAon Layer SecAon Layer SecAon Layer SecAon Layer Line Layer Line Layer Path Layer ConnecAon 6

17 7 Bit Interleaved Parity (BIP) Sent Calc =

18 Error ReporAng: SecAon B B ADM2 DXC R2 R ADM B B unidirec=onal errors from right to le\ 8

19 Error ReporAng: Line B2 ADM2 DXC R2 R ADM B2 M unidirec=onal errors from right to le\ 9

20 Error ReporAng: Path ADM2 DXC R2 R ADM B3 G unidirec=onal errors from right to le\ 2

21 Summary of Node Status Node Section Line Path NE FE NE FE ADM R R2 DXC ADM2 2

22 PM ClassificaAons CV = code violaaon (parity error) ES = any second in which there is at least one CV, LOF or LOS SES = any second in which K or more CV or an AIS L alarm are counted UAS L = consecuave SES L FC L = number of failure events 22

23 Performance Categories Signal State BER Action Anomaly Normal -8 TCA Degrade BER-SD -5-7 SNC/N Switch Soft Failure BER-SF -4 SNC/I or Hard Failure LOS, LOF, AIS-L Mesh Switch 23

24 Alarms: UnidirecAonal Failure AIS P AIS L ADM2 DXC R2 R ADM RDI L RDI P 24

25 Alarms: BidirecAonal Failure AIS P AIS L AIS L ADM2 DXC R2 R ADM RDI L RDI L RDI P RDI P 25

26 OTN Provides OA&M to DWDM Systems: Ethernet Circuit P2P Ethernet Circuit ConnecCng Customer Routers in Atlanta and Indianapolis A. OADM at Birmingham reports Loss of Signal (LOS) B. Downstream transponder suppresses laser C. Upstream transponder suppresses laser; customer routers do not need to run BFD!

27 OTN Provides OA&M to DWDM Systems: SONET Circuit A. OADM at Charlose reports Loss of Signal (LOS) B. A SONET AIS L alarm is transmised towards the customer router at Washington C. The customer router responds by transmitng a SONET RFI L alarm D. The DWDM terminal at Washington reports the SONET AIS L alarm on its trib port E. The DWDM terminal at Atlanta reports the SONET RFI L alarm on its trib port

28 Forward & Backward Defect Indicators in OTN Loss of Signal alarm displayed at Birmingham The ten opacal channels between Birmingham and Atlanta each support a BDI alarm The single cross connect at Birmingham between DLMs facing Atlanta and Nashville propagates an FDI alarm.

29 Payload Problems. Path not terminated. UNEQ 2. AIS P 2. Path trace mismatch (J) 3. Loss of Pointer 4. Payload label mismatch (C2) 29

30 Infinera Port Loops /2 Atlanta New York Terminal Loop at Atlanta Atlanta New York Facility Loop at Atlanta

31 Infinera Port Loops 2/2 Atlanta New York Terminal Loop at Atlanta Atlanta New York Facility Loop at New York

32 CoreDirector Path Level Loops /2 A 6 : 3 A 3 :9 92 ATLA Equipment loop on drop side GTP at ATLA NEWY A 7 : 3 A 2 :89 9

33 CoreDirector Path Level Loops 2/2 A 6 : 3 A 3 :9 92 ATLA Facility loop on line side GTP at ATLA NEWY A 7 : 3 A 2 :89 9

34 Quiz Time! A 6 : 3 A 3 :9 92. Describe the loop applied at ATLA ATLA 2. What alarm(s) will be displayed at NEWY? 3. How many alarms will be displayed at NEWY? A 7 : 3 NEWY A 2 : Draw and describe the other loop that can be applied at ATLA to cause alarms at NEWY

35 Recommended Resources Descrip=on Publisher hsp://preview.anyurl.com/ SONET Poster yjtga6d Agilent Next GeneraAon SONET Poster yas2p3p OTN Poster y8k2u3u Ciena OpAcal Control Plane Poster yeug9ss These colourful A sized wall posters provide an excellent ready reference to the prevalent packet opccal technologies.

36 36 With thanks to Steve Surek of Ciena CorporaAon for discussions regarding OTN