rev. a01 - belver brasil · ethernet basics confidential & proprietary information of veex inc....

Ethernet Basics

Rev. A01

What is Ethernet?

Frame, MAC, VLAN, IP

Ethernet and Cable – Where is Ethernet in Cable?

Key Parameters for Ethernet

How to measure these parameters and verify SLA (Service Level Agreement)

Ethernet Basics Confidential & Proprietary Information of VeEX Inc. 2

Agenda

What is Ethernet?

3 Confidential & Proprietary Information of VeEX Inc.

bit (b):

smallest unit of data, a bit is a 0 or 1

It is the format in which the data is processed by computers

byte (B):

equals 8 bits; also called octet

used to describe the amount of data on a network or in a file

kilobits per seconds (kbps or kbit/s):

measures the speed of data transfer on a network: bandwidth

megabits per second (Mbps or Mbit/s):

measures the speed of data transfer on a network: bandwidth

Bits and Pieces

Ethernet Basics Confidential & Proprietary Information of VeEX Inc.

OSI Model

Invented by Robert Metcalf at Xerox in 1973 and patented in 1976

Xerox convinced Intel and Digital to join in making products (group called DIX)

IEEE standardized in 1983 (802.3 Ethernet) and ISO standardized in 1989

A Little History

10/100/1000T/1000X

10Base2 10Base5 10BaseT 10BaseF

Media 50-Ohm Coax 50-Ohm Coax Cat 3, 4, 5 UTP,

2 pairs

Multimode Fiber

(Single mode fiber)

Max Segment

length

185 m 500 m 100 m 2,000m

(10,000 m)

Connector BNC AUI RJ45 SC/LC

100BaseTX 100BaseFX 100BaseFX

Media Cat 5 UTP 2 pairs Multimode fiber Single-mode fiber

Max Seg. Len. 100 m 2,000m 10,000 m

Connector RJ45 SC/LC SC/LC

1000BaseT 1000BaseSX 1000BaseLX 1000BaseZX

Media Cat 5E UTP

4 pairs

850 nm

62.5 or 50 µm Multimode

1310 nm

50 µm Multimode

Or 9 µm Single-mode fiber

1550 nm

Single-mode fiber

Max Seg. length 100 m 500 m (50 µm)

220 m (62.5 µm)

10 km (SM)

550m (MM)

100 km

Connector RJ45 SC /LC SC/LC SC/LC

Wiring and “Connectors”

SFP (850 nm)

Unshielded Twisted Pairs RJ45

LC Connector

Half Duplex vs. Full Duplex

Auto Negotiation Conflict

Local Device

Advertised

values

Link Partner

Advertised

values

Local Device

Results

Link Partner

Results

Comments

AUTO-NEG AUTO-NEG 100BT/F-DPLX 100BT/F-DPLX Link at max capability

100BT/F-DPLX AUTO-NEG 100BT/F-DPLX 100BT/H-DPLX Problem: Duplex mismatch

100BT/H-DPLX AUTO-NEG 100BT/H-DPLX 100BT/H-DPLX Link ok, but link partner

defaults to H-DPLX

100BT/F-DPLX 100BT/F-DPLX 100BT/F-DPLX 100BT/F-DPLX Valid manual configuration

100BT/H-DPLX 100BT/H-DPLX 100BT/H-DPLX 100BT/H-DPLX Valid manual configuration

100BT/H-DPLX 100BT/F-DPLX 100BT/H-DPLX 100BT/F-DPLX Problem: Duplex mismatch

10BT 100BT - - Problem: No link

10BT/F-DPLX AUTO-NEG 10BT/F-DPLX 10BT/H-DPLX Problem: Duplex mismatch

10BT/H-DPLX AUTO-NEG 10BT/F-DPLX 10BT/H-DPLX Link ok, but link partner

defaults to H-DPLX

10BT/F-DPLX 10BT/F-DPLX 10BT/F-DPLX 10BT/F-DPLX Valid manual configuration

10BT/H-DPLX 10BT/H-DPLX 10BT/H-DPLX 100BT/H-DPLX Valid manual configuration

10BT/H-DPLX 10BT/F-DPLX 10BT/H-DPLX 10BT/F-DPLX Problem: Duplex mismatch

Ethernet Frame Format

FCS / CRC

Type / Length

Source

Address

Destination

Address

Preamble: 7 Bytes

Start of Frame Delimiter: 1 Byte

Destination MAC Address: 6 Bytes

Source MAC Address: 6 Bytes

Data: 46 to 1500 Bytes long

Frame Check Sequence: 4 Bytes

Length of Frame or Type of Data: 2 Bytes

Preamble

MAC address = Unique hardware address

associated with each device

6 Bytes long, represented in hexadecimal format

MAC Address Format

00 - 00 - 00 - FF - FF - FF

Assigned by IEEE to Vendor : 3

Bytes User Value

Source MAC Address = identifies who is sending

the frame

Destination MAC Address = identifies the station

that should receive the frame

Ethernet Frame Data size = 64 to 1518 bytes = 512 to 12144 bits

Overhead = 7 bytes (Preamble) + 1 byte (SFD) + 96 bits (IPG) = 160 bits

Frame rate = Max data rate/(Data size + Overhead)

Frame Rate vs. Efficiency

Data size

Overhead

per frame

Frames

second

Total bits lost

(overhead)

Percentage

of bandwidth

64 Bytes (512 bits) 160 bits 1,488,095 238,095,238 23 %

128 Bytes (1024 bits) 160 bits 844,594 135,135,135 13 %

512 Bytes (4096 bits) 160 bits 234,962 37,593,984 3.7 %

1024 Bytes (8192 bits) 160 bits 119,731 19,157,088 1.9 %

1518 Bytes (12144 bits) 160 bits 81,274 13,003,901 1.3 %

Ethernet

IPG Ethernet

Minimum allowed IPG is 96 bit time:

96 nanoseconds at 1000T/X 0.96 microseconds at 100T 9.6 microseconds at 10T

Hubs, Switches and Routers

Layer 3

Network

Layer 2

Data Link

Layer 1

Physical

Level of Intelligence and Complexity

SWITCH BRIDGE

ROUTER

Layer 3

SWITCH

IP address is 32 bits (4 bytes) in length

Allows for 4,294,967,296 unique addresses

How many addresses does IPv6 provide?

340, 282, 366, 920, 938, 463, 463, 374, 607, 431, 768, 211, 456

IP Header

Ethernet and Cable

Where is Ethernet in Cable?

Residential and Commercial

RAN CE

Generic term for a mobile network node/site, such as a RAN network Controller or RAN Base Station

RAN NC

A single network controller or a site composed of several network elements including:

OSS, WCDMA Radio Network Controller or Synchronization Server

Cellular Backhaul

Terminology used in the MEF specification

GIWF Generic Inter-working Function

PCP Priority Code Point

PEC Packet based Equipment Clocks

PTP Precision Time Protocol

RAN Radio Access Network

RAN BS RAN Base Station

RAN CE RAN Customer Edge

RAN NC RAN Network Controller

RNC Radio Network Controller

Determining the layer of testing and the nature of the link under test

Connectivity

Physical connectivity

Layer 2 and up connectivity

Throughput

Burstability

Latency/Jitter

Key to know that Layer 1 is properly connected

Without Layer 1, no additional tests will be successful

Connectivity

Ethernet drops bad packets

Need to know how many frames to be received in order to

provide accurate Throughput

Errors in packets = Drop Packets

BERT vs. Throughput

Ethernet is bursty

Burst testing verifies ability to transmit burst traffic

Burstability

Latency is time from A to B

Jitter is variation of time from A to B

Critical for time-sensitive application

(Banking/Trading, VoIP, IPTV)

Jitter/Latency

How to …

Measure parameters and SLA

Layer 1

Verify Link Up and MDI settings

Verify Speed, duplex and flow control

Connectivity

Layer 2 and 3

Layer 2, verify MAC connectivity

ARPing the address

Layer 3 connectivity, verify IP

address is valid before doing any

additional test

BER Testing

Familiar concept

Throughput Testing

Better but not complete

All in one RFC2544

Frame loss

Burstability

Jitter

Latency

And what about T-PUT and others

RFC2544

Various Frame Sizes

All tests in one set of measurements

Provide A to B and B to A results to

identify the direction of the network

having problems (if any)

Asymmetric Network = Asymmetric Testing

Performing RFC2544

Latency

Jitter

Burst Test

Performing RFC2544

Frame Loss

What is Ethernet?

Bits and pieces, the layers, Frame, MAC, IP, VLAN

Ethernet and Cable

Ethernet is everywhere or almost everywhere

The key parameters?

Green Light Red Light is not enough

How to…

Summary

Thank you. Any questions?

33 Ethernet Basics Confidential & Proprietary Information of VeEX Inc.

rev. a01 - belver brasil · ethernet basics confidential & proprietary information of veex inc....

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