GigE & 10GigE Ethernet Technology Overview & Testing Approaching

Transcription

1 GigE & 10GigE Ethernet Technology Overview & Testing Approaching Ray Lanier Concord Communications Associates, Inc. 214 South Main Street Concord, NH Tel: Fax:

2 Agenda Ethernet Fundamentals OSI Model Ethernet and SONET comparison Physical Layer (Layer 1) Ethernet Frames (Layer 2) Virtual LAN (VLAN) Concept Auto-Negotiation Process Flow Control Pause Frames

3 The OSI Layer Model The OSI (Open Systems Interconnect) model defines layers in a network. Understanding the function of each layer is key in understanding data communication within Local, Metropolitan or Wide networks. Layer 7 Layer 6 Layer 5 Layer 4 Layer 3 Layer 2 Layer 1 Application Presentation Session Transport Network Data Link Physical Concerned with the end-users particular application Provides for the representation of data Performs administrative tasks and security Ensures end to end error free delivery Handles addressing and routing between elements Handles transfer of data over the channel Handles physical signaling, including connectors, timing, voltage TCP, UDP IP, IPX ATM, Frame Relay, Ethernet T1, SONET HTTP,FTP etc

4 How does Ethernet fit into OSI Model? Ethernet is generally placed in Layer 2 Data Link Layer of the OSI model Ethernet can be transported as follows: Ethernet over DWDM this is a Layer 1 service Ethernet over SONET could be a Layer 1 or Layer 2 service, depends on the network element deployed Ethernet Routed Network this is a Layer 3 service

5 SONET / Ethernet Comparison OSI Layer Model SONET Layer 1 10/100/GigE and 10GigE LAN Layer 1 and 2 Application Application Presentation Presentation Session Session Transport Transport IP ATM SONET Network Datalink Physical Network Datalink Physical IP Ethernet Ethernet

6 SONET SONET / Ethernet Comparison Ethernet Synchronous Timing Asynchronous Timing OC-12 RING

7 SONET / Ethernet Comparison SONET Designed for voice traffic Fixed frame size Constant bit rate Ethernet Designed for data traffic Variable frame size Bursty Traffic SONET 10/100/GigE and 10GigE LAN Bit Rate SONET Ethernet Time

8 Layer 1 Physical Layer Fiber Principles and Copper Characteristics

9 Ethernet Physical Layer Media 10/100 and GigE Most Common Physical Media for 10/100 and GigE 10/100 Ethernet: 10BaseT/100BaseTX Gigabit Ethernet: 1000BASE-SX (850 nm, Multi-Mode Fiber) 1000BASE-LX (1310 nm, Single-Mode/Multi-Mode Fiber) Other Interfaces Gigabit Ethernet 1000BASE-CX, 1000BASE-T copper 1000BASE-ZX (80km, 1550nm, single mode) 100 Mbps 100BaseFX (multimode fiber) Application Presentation Session Transport Network Datalink Physical

10 10GigE Physical Layer Media 10Gig E LAN Application 10Gig E WAN Presentation Session Transport Network Source: IEEE 802.3ae Datalink Physical

11 Layer 2 Ethernet Frames

12 Ethernet Link (Layer 2) Establishment Physical Layer has to be active: This means the optical signal has to be received Ethernet Synchronization (for example, 1.25 Gbps) achieved Physical Link Established (Auto-negotiation must be achieved) If Physical Layer healthy, Ethernet frames can be send to verify traffic and throughput Layer 2 traffic (Ethernet frames) can be transported over the link Each Ethernet node has a unique address, called a MAC address, assigned to it by the manufacturer All traffic originating on that node has its MAC address populated into a source address field in the Ethernet frames All traffic destined for that node will have its MAC address populated into the destination address field by the originating node Application Presentation Session Transport Network Datalink Physical

13 Ethernet Frames Preamble (7) SFD (1) DA (6) SA (6) L/T (2) Data ( ) FCS (4) Same frame regardless of rate - 10Mbps, 100Mbps, 1Gbps or 10Gbps LAN Variable Frame Size 64 bytes to 1518 bytes (excluding Preamble and SFD) Must have an integer number of bytes in every frame Note testing practices Undersized frames less than 64 bytes are considered errors Jumbo frames larger than 1518 bytes are considered valid frames Preamble (7) SFD (1) DA (6) SA (6) L/T (2) Data ( ) FCS (4) Preamble - allows physical layer to detect carrier and acquire sync (7 bytes of alternating 1 s and 0 s) SFD - Start of Frame Delimiter - identifies the beginning of a frame (1 byte )

14 Ethernet Frame More Detail Preamble (7) SFD (1) DA (6) SA (6) L/T (2) Data ( ) FCS (4) Addresses DA - Destination Address SA - Source Address Each source address is unique First 3 bytes identify manufacturer of equipment, assigned by IEEE Length/Type Field frame - indicates length of data field (<=1500) Ethernet Type II (DIX) frame - indicates type of frame data (>=1536) Preamble (7) SFD (1) DA (6) SA (6) L/T (2) Data ( ) FCS (4) Fields used for FCS calc Ethernet Frame FCS Calculation Data the payload -> next layer up (IP, IPX, etc.) FCS - Frame Check Sequence - A 32-bit cyclic redundancy check performed on the frame for error detection FCS - a primary measurement to verify that your Ethernet pipe is good!

15 VLAN (Virtual Local Area Network) Preamble (7) SFD (1) DA (6) SA (6) VLAN (4) L/T (2) Data ( ) FCS (4) TPI Priority CFI VLAN ID 2 bytes 3 bits 1 bit 12 bits 1 Gigabit trunk Used to channelize traffic (pipe with in a pipe) Can also be used to differentiate and prioritize traffic Contains 4 fields: Tag Protocol Identifier - Fixed at hex for Ethernet User Priority - Used to prioritize different types of traffic Canonical Frame Identifier - used only in Token Ring VLAN ID - Specifies the VLAN group (value is 0 to 4095) IPTV High Priority Traffic Internet Browsing Low Priority Traffic

16 Auto-Negotiation Process Mechanism used to negotiate the speed and duplex configuration of the link between two partners Only applies to 10/100 and GigE - not to 10GigE If Auto-Neg is ON (enabled): Each node advertises capabilities to the other Each node will configure themselves to the highest common denominator of their partner s capabilities and their own Key parameters advertised: Half Duplex/Full Duplex Flow control capabilities If Auto-Neg is OFF (Disabled): Link will come up IDLE IMPORTANT - Both link partners must have settings for Auto-negotiation matched (either enabled or disabled on both ends), otherwise a negotiation mismatch will result and link will not be established

17 Flow Control Process Mechanism used to control network congestion and prevent traffic from being dropped Applies to 10/100, GigE and 10GigE interfaces PAUSE Frames Uses a defined MAC control frame format Contains a time field that defines PAUSE time Receipt of a PAUSE frame causes Ethernet device to cease transmission for PAUSE time

18 Ethernet over SONET (EoS) Service Customer GigE Switch Ethernet Link A Cisco SONET Link SONET Ring OC-48 or OC-192 Ethernet Link B Service getting more complex: Point to point or switched 10/100 and Gigabit interfaces Not always a full Gigabit - configurable bandwidth in STS increments Flow control may be enabled

19 Ethernet over SONET (EoS) Service Transport Circuit Size % GE Interface Speed Bandwidth in Mbps STS STS3c STS6c STS9c STS12c STS24c STS48c Relationship between SONET mapping and maximum throughput

20 Turn-up, Acceptance, and Troubleshooting Ethernet/IP Transport Networks Ray Lanier Concord Communications 214 South Main Street Concord, NH Tel: Fax:

21 Agenda Testing a network Basic structure of an Ethernet/IP Network Parameters to test Throughput, Frame Loss, Latency, and Jitter Limits of basic testing Transport Testing Testing a bit Transparent Link Testing an Ethernet over SONET Link Testing a packet Switched Link Ethernet Transport Testing Demo JDSU Ethernet Turn-up Product

22 Basic structure of an Ethernet/IP Network Purpose of test is to check the backbone for errors Edge Processing Equipment Edge Transport Equipment Transmission technique LAN/NE CE PE PB PB PE CE LAN/NE Packet oriented Ethernet Access Switching technique Backbone, Core WAN, Metro, Satellite Access

23 Testing Responsibility of Transport Groups Test is run from one LAN to another, placing a tester where the enterprise router used to be and testing the transport layer Application Layer End-to-End Transport Layer LAN/NE CE PE PB PB PE CE DWDM SONET Satellite LAN/NE Ethernet/IP Ethernet/IP Responsibility of Transport Groups

24 Throughput Do I get my full pipe? Affected by The max bandwidth link set up between two locations (e.g. SONET NE) Network Overhead Whether network elements are setup properly Customer Complaints For VoIP if the customer can only place min # of call at a time successfully For Data if the customer states that during peak hours the internet slows down Detailed Comments Throughput is the key result of a test Audio Frame loss, latency & jitter should be checked at max throughput for transport quality Best way to test throughput: Generate a constant load at max throughput rate.

25 Round Trip Time (Latency) Network Delay Affected by Priority queuing and traffic shaping problems Network Congestion Length and type of Link Customer Complaints For VoIP when the customer complains of Over talk and echo For Data if the customer complains of extreme load times for web pages Detailed Comments Key time to test round trip time is when throughput is at max on the link, to ensure that buffering and live traffic is not going to drastically delay the Round Trip Time Because a ping is done using IGMP (Internet Group Management Protocol) routers handle these at a lower priority than traffic, pinging produces an inaccurate latency measurement TIMESTAMP 4 TIMESTAMP 3 TIMESTAMP 2 TIMESTAMP 1 1 TIMESTAMP 2 TIMESTAMP 3 TIMESTAMP 4 TIMESTAMP

26 Packet Loss Parameter Affected by Buffer overruns in network components Network Congestion Bad network elements Customer Complaints VoIP packet clicks & fuzziness or even dropped calls in extreme situations Again for Data complainants of extreme load times (TCP retransmissions) Complains of no throughput it may be due to excessive packet loss Detailed Comments The best way to check packet loss is by having a sequence number in every packet to see on the receiving side if any packets were lost or erred in transit Note this test should be run at max throughput as most packet loss problems can t be seen unless the network and queues are being stressed Three Packets In Two Packets Out Home Core IP Network/ Gateway

27 BERT versus packet oriented testing Packet based testing is the future of switched links though BERT is the past and can still be useful on bit transparent links 40 bit sequence of 4 packets Bit errors 4 (10%) (0%) Throughput (25%) (75%) Ethernet frames/packets are dropped if they contain a single error Assuming 1518 byte packets, a BER of 8e-5 can lead to a 99.99% throughput or a 0% throughput rate depending on when the errors are distributed!!! Bottom Line is a Packet Error Rate is key in the IP world, not the BER rate like we are all used to

28 Packets Equally spaced Packet Jitter Packet Jitter = variation in arrival time between packets Packet Jitter = variation in arrival time between packets Affected by Variation in network traffic levels Network Congestion Priority queuing and traffic shaping problems in combined VoIP / data networks Customer Complaints For VoIP packet clicking and popping noises to the end user For VoIP garbled speech Detailed Comments Note Jitter is important for testing in networks that use VoIP or IPTV. It is NOT generally critical in data only networks Variation in packet spacing (jitter)

29 Transport Techniques

30 Two key things to remember about Ethernet 1. Ethernet frames that are errored (FCS errored frames) will be discarded by Ethernet-aware devices. 2. Devices with Ethernet Intelligence (switches, routers) can not be hard-looped like a physical layer (T1, etc) device. When performing testing on a Layer 2+ Ethernet network or element, you cannot use hard loop-backs and expect to get the traffic back

31 CE - Access Ethernet link Idles Testing links Bit Transparent Link Frame 1 Gbps The most important features: PE - Adaptation on bit level Fiber Patch Opt. MUX NewSDH/GFP-T 1 Gbps Idles Backbone Frame Dark fiber Opt. channel SDH VCG Ethernet access rate and BB transport rate must be of the same. Ethernet link is transferred bit transparent. Per Ethernet link a separate transport channel (fiber, opt. channel, SDH VCG). Very small delay time. No packet switching; No Store & Forward; No prioritization Bit errors and errored packets are forwarded. GFP-T: Transparent Generic Framing Procedure VCG: Virtual Concatenation Group

32 CE - Access Test links Packet Switched Networks Ethernet link Idles Frame 100 Mbps The most important features: PE - Adaptation on packet level FCS Ethernet access rate und BB transport rate can be different. Ethernet link is transferred packet based. For identification the PE inserts a tag/label. Multiple Ethernet links can be transferred in a single BB trunk. Store & Forward causes delay and delay variation. With packet switching; probably with prioritization Bit errors and errored packets are not forwarded. Store&Forward L2/3 Packet Switching + VPN Backbone Packet loss Frame pro Eth. Link < = 100 Mbps Total link 1 GigE or 10 GigE

33 Testing Ethernet over SONET (EoS) Loopback Mode FST-2802 FST-2802 Ethernet Link A Cisco SONET Link SONET Ring OC-48 or OC-192 Ethernet Link B How to test EoS Service: Hard loop generally no longer certainty Depends on network element FST-2802 generates traffic at customer premise FST-2802 in CO loops traffic back Verify: Connectivity Link Through Put Ethernet frames QoS no FCS errors

34 Turn-up of multiple services (VoIP, Video, Data) Test goal Multiple Services : Prove 100% availability of the transmission bandwidth as a whole and divided on the individual service classes (VoIP, Video, Data). Service-related (VoIP, video, data) QoS proof is required. Control of the bandwidth management (Prioritization, bandwidth rate limitation) QoS parameters per service: Throughput, Packet Loss, Round Trip Time, Packet Jitter Test method: Measurement setup is possible only with two testers. Physical loop is not permitted. Generate Multiple Streams with service-typical load profiles, in order to stimulate the test link in accordance with the later services. RFC-2544 is not meaningful. RFC-2544 checks general performance and not service-related performance. E.g. if one service is limited by low prioritization level, the coordination of the zeroing process is rather complex.

35 Ethernet Transport Testing Demo GigE 1.25 Gbps Single Mode Fiber Connection JDSU FST-2802 JDSU TB-8000

36 JDSU Ethernet Turn-up Product - Summary TB-8000 FST-2802 HST-3000 SmartClass High-end Modular High-end Modular Platform Platform Single or Dual Port Single or Dual Port (10/100/100 + Optical (10/100/100 + Optical GigE) GigE) Single port 10GigE Single port 10GigE L1/L2/L3 Testing L1/L2/L3 Testing RFC2544 RFC2544 Remote Control Remote Control Other Transport Other Transport Technologies Technologies (SONET/SDH, T/E-Carrier (SONET/SDH, T/E-Carrier etc.) etc.) First Ethernet Solution First Ethernet Solution Single or Dual Port Single or Dual Port Ethernet and FC Ethernet and FC L1/L2/L3 Testing L1/L2/L3 Testing RFC2544 RFC2544 Multiple Streams Multiple Streams Graphical Results Graphical Results PDF Printout PDF Printout Random Frame Size Random Frame Size IP/VLAN Discovery IP/VLAN Discovery Remote Control Remote Control Modular Platform Modular Platform Single Port Term Single Port Term Dual Port Thru Dual Port Thru Cable Diagnostic Cable Diagnostic L2/L3/L4 Testing L2/L3/L4 Testing RFC2544 RFC2544 Multiple Streams Multiple Streams VOIP/Video Test VOIP/Video Test Applications Applications Remote Control Remote Control Other Access Other Access Technologies (E1/T1, DSL Technologies (E1/T1, DSL Copper) Copper) Point solution Point solution Single Port Single Port Cable Diagnostic Cable Diagnostic L2/L3 Testing L2/L3 Testing RFC2544 RFC2544 Loopback Device Loopback Device Low Cost Low Cost

37