An SAIC Company
Gigabit Ethernet: Is it a disruptive technology?
Ronald Skoog
Telcordia Technologies 732-758-2406
LTS
Outline
y
Background:
– The Metro Network Environment and the Technology Choices
y
Ethernet and Gb/10Gb Ethernet Technology Background
y
Gb/10Gb Ethernet Capabilities and Deficiencies
y
Related Standards and Industry Forum Activities and Service
Providers
LTS
Metro Network Environment
LAN
Internet
backbone
LAN
ISP
POP POPISP
ASP SSP
MAN
BOTTLENECK!!
• SONET-based TDM networks • Inefficient for data traffic
• stranded capacity, • no statistical gain • Long provisioning times
y Business Services/Apps
– Access to Internet, ASPs, SSPs, etc. – LAN-LAN, VLANs, VPNs
– Flexible, granular bandwidth choices – Quick and efficient service provisioning – Voice and video
Residential Services/Apps xDSL, Cable, ETTH HDTV Video Games Voice
Residential
New Alternatives to SONET
Next Generation MAN
Next Generation MAN
WDM
WDM
LAN
Internet
backbone
MAN
MAN
LANLAN
ISP
POP POPISP
MSPP NG SONET (VC, GFP) Gigabit Ethernet
New Solutions
RPR DPT iPT ATM VP RingMAN
MAN
-nDS0, T1, T3 Leased line - TDM-based SONETResidential
Bottle neck !LTS
Ethernet Protocol Structure
Data Link Application Presentation Session Transport Network Physical OSI Model Layer 7 Layer 6 Layer 5 Layer 4 Layer 3 Layer 2 Layer 1
Major IEEE Sublayers
Ethernet-Specific 802.2 802.3 802.1D 802.1Q 802.1p
Ethernet Frame Structure
Preamble Destination MAC Address Source MAC Address Length/ Type Data/LLC Frame Check Sequence 64 bits 48 bits 48 bits 16 bits 46 to 1500 Bytes 32 bits
1518 Bytes ≥ Length ≥ 64 Bytes Physical Signaling
Media MAC Bridging Media Access Control
(MAC) Logical Link Control
Evolution from Shared-Media, Half-Duplex to
Dedicated-Media, Full-Duplex
10BASE2 or 10BASE5 (Coax Cable, Bus Topology, 1985) Collision (CSMA/CD resolution)
Collision (CSMA/CD resolution) Repeater
UTP
UTP
UTP
UTP
Half-Duplex 10BASE-T (Star Topology, UTP cable, 1990) Dedicated Media
Bridge/Switch
Collision-Free
UTP UTP The Critical Development
• LAN backbone and NIC speeds are independent • Networking is now
LTS
Switched GbE Network Architecture
LAN 1 LAN 2 LAN n •• • Multi-Tenant Unit Building (MTU) Access GbE
Switch Core GbE
Switched Network GbE GbE IP Backbone Providers Access GbE Switch GbE Server Farm GbE Multi-tenant Building Multi-tenant Building Multi-tenant Building ASPs ISPs GbE Architecture GbE L2
Switch GbE L2/3Switch
Optical Ethernet Service Categories
• Internet access
• LAN-LAN Interconnection (Ethernet PL)
• Metro Transport (Transparent LAN Service)
GbE and SONET Network Architectures
LAN 1 LAN 2 LAN n •• • Multi-Tenant Unit Building (MTU) Access GbESwitch Core GbE
Switched Network GbE GbE IP Backbone Providers Access GbE Switch GbE Server Farm GbE Multi-tenant Building Multi-tenant Building Multi-tenant Building ASPs ISPs GbE Architecture SONET Architecture RFT RFT RFT Office TM OC3 OC12 ADM OC12 OC48 DCS ADM (hub) OC48 Collector OC12 OC48 DCS ADM ADM Core Ring IXC ATM ISP OC3-OC12 GbE L2
LTS
10 Gigabit Ethernet Layer Architecture
•At Layer 2, 10 GbE is mostly unchanged, except NO SHARED MEDIA • Two Physical (PHY) Layers: LAN PHY and WAN PHY
• Multiple Physical Media Dependent (PMD) layers: – MMF and SMF
– Minimum distance requirements from 65 m to 40 km
802.3 Media Access Control Reconciliation PCS XGMII WIS PMA PMD PMA PMD MDI MDI Medium (Optical Fiber) LAN PHY WAN PHY 850 nm Serial (MMF) 1310 nm Serial (SMF) 1550 nm Serial (SMF) 1310 WWDM Parallel (MMF, SMF) PHY
64B/66B coding for Serial PMDs 8B/10B coding for WWDM PMD
10 GbE Applications
Metro Network Core Routers Edge Routers Access Routers • • • DWDMLong Haul Network
Server Farm Connectivity Long Haul Links
WAN PHY Core Routers
10GbE GbE 10GbE 10 GbE 10 GbE 10GbE 10GbE 10GbE • • • Regional/Metro Access Routers Edge/Core Routers 10GbE GbE 10GbE 10GbE ELTE* WIS Path
LTS
Gb/10Gb Ethernet Capabilities
y
Full duplex point-to-point links with long reach to 40 -70 km
y
Big port cost advantage over SONET and ATM (~8:1 in port costs)
y
‘Plug-and-play’
y
VLAN capability (802.1Q)
y
Spanning tree routing (802.1D) at layer 2
y
Aggregate link capability (802.3ad)
y
Priority capability (aggregate flow QoS) provided by 802.1p at
Layer 2 and DiffServ at layer 3
y
Policy based QoS
y
Traffic policing, shaping and monitoring at customer interface
Optical Ethernet has a significant arsenal of
Networking Capabilities
Gb/10Gb Ethernet Deficiencies
y
Protection/restoration times are on the order of 1 second
compared to SONET 50 ms capability
y
QoS is in a similar state as IP QoS
– over-provisioning needed to provide delay/jitter sensitive apps.
– QoS provided for traffic aggregates, not individual flows
– Routing protocols don’t balance load very well on link capacity
y
Performance monitoring and fault management are not as good
as SONET and ATM.
– Ethernet provides no overhead for performance monitoring,
alarms, protection signaling, etc.
y 10GbE WAN PHY has some of this capability
y
Not clear how well GbE OA&M will scale (e.g., service
provisioning, loopbacks, single-ended maintenance)
LTS
Missing OAMP Functionality in Ethernet
y
Fault Detection, Sectionalization, and Alarming
y
Protection and Restoration (SONET: 50msec)
y
Secure Single-Ended Maintenance
y
PHY-Layer Link Quality Monitoring (BER)
Why is Ethernet Cheaper?
y
Simple Technology
y
Backwards Compatibility
y
Strict Standardization and Interoperability
y
Customer Familiarity and Acceptance
y
Large Volumes
ELECTRONICS:
Byte-oriented
Line coding (e.g, 8B10B) Simple frame delineation
OPTICS:
High-Volume, Mass Assembly Plastic Packaging
Source: Martin Nuss, Internet Photonix
LTS
Spanning Tree Capability (802.1D)
y
Routing in layer 2 switched networks uses the spanning tree
algorithm
–
spanning tree routing is prone to traffic concentrating on a small
number of links and switches;
–
spanning tree reconfiguration is relatively slow (30-50 seconds
required);
•
An improved algorithm is being developed (P802.1w) that will
converge in < 1 sec. (maybe in 10s of ms)
•
Multiple spanning tree capability is being developed in P802.1s
L2 Switch L2 Switch L2 Switch L2 Switch L2 Switch LAN LAN LAN LAN LAN
Spanning Tree Links
SWITCHES LEARN TOPOLOGY BY EXCHANGE OF CONFIGURATION MESSAGES
L2 Switch
Virtual LAN (VLAN) Capability
y
Virtual LAN and priority capabilities are provided by 802.1Q/p:
– a VLAN tag is provided by 802.1Q to identify VLAN membership
y Limited to 4096 VLANs – this is a potential scalability issue
– the VLAN tag has a 3-bit priority field that allows 8 possible service
classes (matches DiffServ’s 8 possible classes)
y
Why VLANS?
– LAN scalability:
y limits broadcast domains (limits broadcast storms);
y also limits multicast, chatty protocols, etc., reducing overall network traffic.
– Network efficiencies: traffic flows from different VLANS can be
segregated
– Allows non-physical grouping of nodes that share similar resources
– Allows easy changing of LAN membership
– Reduces the amount of level 3 (IP) routing
– Security: limits snooping; authentication required (via GVRP) to join
LTS
VLANs and MPLS-Based Transparent LAN
Services
LER LER LSR LSR LSR LER LER LER LER CPE CPE CPE CPE CPE B A A A B VC LSP Tunnel LSP VC LSP Ethernet VLAN Ethernet VC Label Tunnel Label Etype 0x8847 DA SA Original Ethernet Frame Label Stack Outer Ethernet Header 32 bits 16 bits16 bits Preamble Dest MAC Address Source MAC Address 64 bits 48 bits 48 bitsLength/ Type Data/LLC Frame Check Sequence 16 bits 46 to 1500 Bytes TPID TCI User Priority (3) CFI (1) VLAN ID (12) Architecture based on Martini IETF Draft
Related Standards and Industry Forum
Activities
y
Resilient Packet Ring (RPR) – IEEE 802.17
– Data efficient ring (distributed switch) using spatial reuse, 50 ms
protection, and bandwidth management (allocation and fairness)
y
Ethernet in the First Mile (EFM) Study Group – IEEE 802.3ah
– Remote management of customer terminal for testing (loopbacks)
– Link OAM overhead for BER monitoring, alarm indication, etc.
y
ITU Study Group 13 (Multi-Protocol and IP-based Networks & ...)
– Link OAM and end-to-end OAM
– Leverage link OAM from EFM
y
Metro Ethernet Forum (Industry Alliance)
– Ethernet service definitions, technical specifications, and interoperability
– MPLS protection mechanisms to 50 ms protection
LTS
Service Providers with Ethernet Services/Plans
W orldC om Level 3 W illiam s C om m unications S print G lobal C rossing A T& T B roadw ing Traditional IXC s E m erging IXC s Telseon XO C om m unications S phera
Tim e W arner Telecom O nFiber
G roup Telecom (C anada) Looking G lass
E lectric Lightw ave E P IK C om m unications
Full S ervice C LE C S E m erging m etro/regional carriers
V erizon S B C C om m unications Yipes Q w est IntelliS pace B ellS outh Fiber C ity B ell C anada C ogent ILE C S E LE C S W orldC om Level 3 W illiam s C om m unications S print G lobal C rossing A T& T B roadw ing Traditional IXC s E m erging IXC s Telseon XO C om m unications S phera
Tim e W arner Telecom O nFiber
G roup Telecom (C anada) Looking G lass
E lectric Lightw ave E P IK C om m unications
Full S ervice C LE C S E m erging m etro/regional carriers
V erizon S B C C om m unications Yipes Q w est IntelliS pace B ellS outh Fiber C ity B ell C anada C ogent ILE C S E LE C S Source: RHK Inc.
Is Gigabit Ethernet a Disruptive Technology?
y
It has a huge cost advantage
– ~8-to-1 in port costs, less in provisioning and operations
y
Currently serving niche markets
– Internet access at 20%–30% equivalent SONET $/bps prices
– IP-based (iSCSI) SAN or data backup solution for smaller sites giving
them Fibre Channel like performance
y
No ‘killer’ issues have been identified
y
There will always be gaps in capabilities,
– but they are getting smaller, and
– closing the gap may not be worth the price
We believe that GbE is likely to be a
Disruptive Technology
LTS
Conclusions
y
The main contenders are Gb/10Gb Ethernet, MSPP technologies
and RPR technology.
– The MSPPs and RPRs may become more Ethernet-based
– The SONET-based MSPPs and RPRs may have more competitive
cost structures
But, GbE Technology will be a Major Player
There is a Race going on at the Optical Edge
y
It is not clear which technology direction will prevail
– Is multi-service/Multi-protocol capability needed, or will
Ethernet become the ubiquitous layer 2 standard?
y
There is no one answer for all networks
– Options need to be carefully considered for each carrier and
