Cell Backhaul:Realities of Ethernet in SLA

EnvironmentsPresented by Zach Sherman

Applications EngineerTransition Networks

MBA, BSEE

Agenda

• Situational Analysis• Upcoming Bandwidth Reality• Choices to make• Can Ethernet perform like TDM• Ethernet Standards to know

Situational Analysis• 200 Trillion Text messages are received each

day in America• An increase by almost 500% in two years• 5 Billion Applications were downloaded in

2010• Mobile web users up more than 33%• Over 50% of phones sold in 2011 are “smart”

phones (<25% in 2009)

Upcoming Reality

• Not enough Bandwidth to towers• Each iPhone/Droid user

– Consumes >560M per month

• Each tablet user– Consumes >800M per month

• That’s a lot of T1’s

Choices to Make• Do I put more T1’s to towers?

– Bandwidth growth has been exponential• How many more T1’s will be enough?

– For two years?– For five years?

• Do I put Ethernet to towers?– How? The infrastructure won’t support it

• Only copper to the tower– If I have the fiber how do I get Ethernet to work

• QoS• SLA’s• Dropped Calls

Ethernet’s RealityEthernet might provide the bandwidth but can I get theservice I expect from T1’s?

• Traditional Ethernet was non-deterministic– Half-Duplex– CSMA/CD

• Random backoff delays• Destruction and Re-transmission of data

• Switched Full-duplex Ethernet– Removes CSMA/CD– Each port is its own collision domain in Full-duplex– 802.1p/Q VLAN’s and Prioritization

• Real-Time Ethernet• The Foundation of Many SLA’s is Time

Ethernet Technologies Aimed at SLA’s• VLAN Tagging

– Q-in-Q• Traffic Classification• Quality of Service Techniques

– Class of Service (CoS)– Differentiated Services (DiffServ)

• IEEE 802.3AH (Link OAM)• IEEE 802.1AG (Service OAM)• ITU-T Y.1731 (Performance Monitoring)• Synchronous Ethernet (SyncE)• IEEE 1588v2• G.8032 Ring Protection

IEEE 802.1Q and VLANs• IEEE 802.1Q, (dot1q) allows logical network connections to share

the same physical network

• VLAN’s logically separate broadcast domains at layer 2– A VLAN is typically used to isolate traffic types logically in an organization

while sharing the same physical network• Both sales and engineering need access to the network, but each has its

own VLAN so that information is protected from one segment to another

• The VLAN tag is a two-byte (16 bit) frame used to identify the traffic circulating on the VLAN– Contains a three-bit user priority (CoS tag)– One-bit canonical indicator– 12 bit VLAN ID

802.1ad – Q-in-Q• Q-in-Q commonly referred to as double tagging

– Allows tagged traffic to be preserved while adding additional tags– Useful for Internet service providers, allowing them to use VLANs internally

while mixing traffic from clients that is already VLAN-tagged. • Customers can use and manage their own C-VLANs for each user group whereas

Service Providers can use their own S-VLAN to isolate traffic from each customer into a VLAN

• An Ethernet frame with Q-in-Q looks like a VLAN-tagged frame, except that it has two tags instead of one

DA SA VID

20

Type

88A8

VID

30

Type

8100

Data FCS

802.1Q802.1ad

5-VLAN Tagging Types

QoS Techniques

Why Quality of Service?

• Delay Sensitive ● High Tolerance For Delay– Voice - Internet Browsing– Streaming Video - Email– Video Conferencing - File Transfer

• QoS defines rules for processing packets – Based on priority or weight

• Class of Service (CoS)• Type of Service (ToS)

IEEE 802.1P Class of Service

• Class of Service (CoS)– Commonly Called the P-Bit

• 3-bit value– Typically associated with a VLAN ID

• Value of 0 to 7– 7 being the highest priority traffic

• Doesn’t Mean Much without Rules

DiffServ – IP ToS• Type of Service – ToS

– Replaced by DiffServ

• Uses 6 bits in the IP header– Allows for 64 traffic classifications

• Table of the Most Common Types

• Doesn’t mean much without processing rules

IP Value Priority

101 110 High Critical

000 000 Best Effort

001 010 Low

000 100 Medium

001 110 High

Two Types of QoS

• Hard QoS– Reserves a selected amount of bandwidth for a traffic type– No other traffic types can use this bandwidth

• Soft QoS– Not a dedicated amount of bandwidth– Allows for flexibility in assignment and re-assignment

Rule Systems

• Strict Priority– Allows an administrator to determine exactly how much

bandwidth is allowable to each flow– More difficult to implement because of the interface to

control

• Weighted Fair Queuing– Weighted Round Robin Queuing– Allows for certain traffic to get a automatically assigned

bandwidth percentage– Automatic nature is simple to implement

WFQ Example• Based on the inbound CoS or ToS tag, each traffic type is

assigned a weight for processing. This weight determines bandwidth percentage

Priority Queue Frame Type Weights

0 Best Effort 1

1 Background 2

2 Excellent 4

3 Critical 8

WFQ equation:

B*Flow (1)Flow(1) +Flow(2) + Flow (3)…+ Flow(n)

802.3ah Link OAM• AKA – Ethernet in the First/Last Mile• Provides for IP-less management of remote

nodes between vendors– Cisco talks to HP, etc

• Provides critical link fault information– Last Gasp/Dying Gasp– Link Failure– Critical Event

• Is Point to Point only (Direct Connection)

www.transition.com

802.1AG/Y.1731 Introduction

Service Provider

Operator Operator

Customer End-to-End Metrics

Provider End-to-End Metrics

Operator Metrics Operator Metrics

Continuity Check Messages

Fault Detection

• Connectivity Check Messages (CCMs) are periodic messages used for detecting loss of continuity within an MA

– Each MEP transmits CCMs to all other MEPs in the MA

– Upon loss of 3 consecutive CCMs a loss of continuity defect is declared

EVC

Failure

Alarm

CCM

NOCCCM Timeout

Alarms

www.transition.com

LoopbackFault Verification

• Works with central test head to perform tests

– Measures performance (delay, dropped packets, throughput, etc.)

– Ideal for fault isolation and locating within carrier network

• Port level loopbacks are ideal for turn up and commissioning

– Eliminates truck rolls

NOC

EVC

Failure

LBR

LBM

www.transition.com

Linktrace

Fault Isolation

• Quickly determine the exact location of a fault

• Tracks the entire path – Hop-by-hop

• Similar to IP Trace Route functionLTR

EVC

Broken Link

LTM

NOC

www.transition.com

AG/Y.1731 OAM SummaryOAM Function 802.1ag Y.1731 Method

CFM

Fault Detection CCM

Fault Verification / Loopback LBM / LBR (“Ping”)

Fault Isolation LTM / LTR

Discovery LTM / LTR & Multicast LBM*

Fault Notification AIS / RDI

PM

Frame Loss CCM, LTM / LTR

Frame Delay DM (1 way), DMM / DMR

Delay Variation DM (1 way), DMM / DMR

Packet Statistics• Y.1731 Provides Transmission Stats

– Frame Delay (FD)• Delay Measurement Messages (DMMs)• Delay Measurement Responses (DMRs)

– Frame Delay Variance (FDV)• The maximum FD less the minimum FD

– FD is an average measurement of delay– Frame Loss (FL)

• Continuity Check Messages (CCMs)– Link Trace Messages (LTMs)– Link Trace Responses (LTRs)

– Frame Loss Ratio (FLR)• Percentage of frames reaching destination

Synchronous EthernetSyncE

– ITU recommendation G.8261

SynchE– ITU recommendation G.8261– Uses the Physical Layer of Ethernet– Clock Singaling is kept separate from Data Traffic– High reliability and accuracy– A Primary Reference clock is inserted through a

separate clock port– Does not interfere with existing IEEE protocols– Uses OAMPDU’s for delivering Synchrozation

Messages (SSMs)– Used only for synchronization of clocks– Does not distribute Time of Day (ToD) messages

IEEE 1588v2• Precision Timing Protocol (PTP)

– Independent of the Physical Layer– Uses Packets to transport timing information– Sends Time of Day (ToD) and Synchronization info– Can be affected by network delays and jitter– Can be used in conjunction with SyncE

• SyncE delivers accurate Frequency/Sync information• 1588v2 delivers ToD

G.8032 Ring Protection

• Ethernet Ring Protection Switching (ERPS)• Sub 50ms Recovery• Protects Ethernet Rings from Link and Node

failures• Offers Ethernet SONET/SDH ring failover and

deterministic performance

Three Solutions from TN

1) 32xT1 over Ethernet2) 802.1ag/Y.1731 NIDs3) SyncE, 1588v2, G.8032 NIDs

32xT1 over Ethernet• PacketBand-TDM Line

T1’s over the Ethernet Core

Keys to T1 over Ethernet• Clocking

– PacketBand exceeds the G.824 SyncMask Standard for Clock Recovery

• <16ppb clocking error rates

• Ethernet Processing– On Board Ethernet switch

• Support VLAN’s, QoS (CoS, DSCP/DiffServ)• Additional Ethernet ports, fiber (SFP & Cu)

– supports Ethernet and TDM delivery ‘in the box’– rate limiting– egress queue prioritization

802.1AG/Y.1731 NIDs• x3230

– Single Port NID with Failover– Fully supports:

• VLANs• Q-in-Q• CoS (802.1P)• DiffServ• Strict Priority Queuing• 802.1AG• Y.1731• Sub 50ms fiber failover

802.1AG/Y.1731 NIDs• S3240

– Multi-Port NID with Failover– Fully supports:

• VLANs• Q-in-Q• CoS (802.1P)• DiffServ• Strict Priority Queuing• 802.1AG• Y.1731• Sub 50ms fiber failover• Dual Redundant DC Power inputs

Uber-NIDs• S3280 & SISGM1040-384-LRT

– Adds features to S3240– More ports (8 total)– 2 Out of Band Management ports– IPv6– 1588v2– SyncE– G.8032– (-40) to 75C temp range– IEC61850 (on SISGM)

• Are the basis for all future NIDs– Includes plans for 10G

Summary• Many challenges related to increasing bandwidth

requirements for mobile services• x number of T1’s may no longer be enough• Ethernet is a viable option for bandwidth• Groups like the ITU, MEF, and IEEE are all working

on continuously improving Ethernet to provide the type of reliability and availability inherent to TDM circuits

• Transition Networks is active in these groups and is staying as informed on emerging standards as they are ratified by the various groups