1. Carrier-Grade Ethernet Technology
Based on the article:
“Ethernet as a Carrier Grade Technology: Developments and Innovations” by
R. Sanchez, L. Raptis, K. Vaxenavakis
Raimena Veisllari TTM1 lecture

2. Outline Repetition of the main Ethernet characteristics
Reasons/Challenges for the Carrier Ethernet development
Standardizations/work in progress
Scalability through VLAN hierarchy
Traffic Engineering (TE)
Operation, Administration and Management (OAM)
Deployment case study

3. The native Ethernet frame
7 octets Preamble for synchronization
SFD ( ) start of MAC frames
48 bit DA/SA
CSMA/CD (do we still need it in switched Ethernet?)
NOTE: When used to identify a hardware instance in new applications, the IEEE/RAC intends to migrate from MAC-48 to EUI-64 identifiers. However, for backward compatibility, this transition be difficult for some 802-related applications. Therefore, policies for allowing selective use of 48-bit identifiers within 802-related systems are being developed (see the following subclause for further details).
MAC-48. A 48-bit identifier used to address hardware interfaces within existing 802 based networking applications
EUI-48. A 48-bit identifier used to identify a design instance, as opposed to a hardware instance. Examples include software interface standards (such as VGA) or the model number for a product.
EUI-64. A 64-bit identifier used to identify each hardware instance of a product, regardless of application, such as wireless devices and computerized toasters, as well as EUI-48 identifier applications.

4. Why did Ethernet “win” in the customer domain?
There are LOTS of LAN protocols
Price!
Performance
Availability
Ease of use
Scalability ….

5. Main characteristics Simplicity (plug n’play) and cost effective
The switching logic (self-configuration)
Listening, Learning and Forwarding
Redundancy through xSTP
VLAN known as a broadcast domain
Connection-less (single hop)

6. Why Carrier Ethernet ?
SP infrastrucure based on legacy circuit-switched SDH/SONET, ATM, frame relay etc.
Ethernet as the technology of choice in the customer domain (85% of all networks and 95% of all LANs)
Internet is packet-switched
Eliminate potential internetworking problems
High bandwidth with simplicity and low cost

7. Carrier Ethernet Definition
The MEF1) has defined Carrier Ethernet as “an ubiquitous, standardized, carrier-class Service and Network defined by five attributes that distinguish Carrier Ethernet from familiar LAN based Ethernet”
Standardized services
Scalability
Reliability
QoS
Service Management 1)

8. Carrier Ethernet Challenges (1)
Moving Ethernet from the LAN to the carrier network brings out requirements/challenges:
Scalability
Support for 10exp6 customers of an SP
Evolving the VLAN-tagging standards
Protection (Reliability and Resiliency)
Achieve the required 50ms recovery time
Problems with xSTP recovery time
Other protocols required

9. Carrier Ethernet Challenges (2)
3. Quality of Service
Hard QoS comparable with the guaranteed service from existing leased lines
Service Management
Service provisioning based to SLAs
Service Monitoring
Troubleshooting
TDM support
Inter-working with existing technologies
(leverage the customer-driven investment)

10. Ethernet Standardization Milestones

11. Scalability through VLAN hierarchy(1)
802.1Q
Management, security and scalability reasons
4094 available VLANs not enough for an SP
Layer3 functions to communicate between VLANs

12. Scalability(2)
Q-in-Q IEEE 802.1ad Provider Bridges adding a new S-VID to the frame, 4094 VLAN limitation for the provider!
A failure in the customer’s domain still affects the spanning-tree of the provider’s core (transport) network

13. Scalability (3)
MAC-in-MAC IEEE 802.1ah Provider Backbone Bridges (PBB) adds a Backbone MAC header

14. Scalability (4) - MAC-in-MAC header encapsulation - 24 bit I-SID
~16 service instances
- Dedicated set of
MAC addresses

15. Scalability through VLAN hierarchy(5)
PBB provides:
1. 24 bit I-SID identifying the service in the SP => 16exp6
services
2. Total separation of the customer and SP networks
The MAC header is added at the edge of the SP
The backbone B-VID used for traffic engineering, ”zone”separation
SP control frames are independent from the customer’s ones
3. Tunneling

16. PBB-Traffic Engineering
PBB-TE 802.1Qay introduce connection-oriented forwarding mode and Ethernet tunnels:
Deterministic service delivery, QoS
Resiliency
OAM requirements
Turning off xSTP
Forwarding is not based on the MAC learning mechanism but provided by the OAM plane

17. Ethernet Services
MEF defines the services as Ethernet Virtual Connections (EVC):
Point-to-point E-LINE
Point-to-Multipoint E-Tree
Multipoint-to-Multipoint E-LAN
Private Leased Lines
dedicated bandwidth
Virtual Leased Lines
shared bandwidth

18. Carrier network with PBT

19. Operation, Administration and Maintenance (OAM)
Important building block toward carrier services Ethernet, multiple working/standardization bodies.
IEEE 802.1ag and ITU-T Y.1731:
Fault detection through Continuity Check Messages
Fault verification through Loopback and reply messages
Fault Isolation through Linktrace and reply messages

20. Operation, Administration and Maintenance (OAM)
ITU-T Y.1731
Fault notification through Alarm Indication Signal
Performance monitoring
Frame Loss Ratio
Frame Delay
Frame Delay Variation

21. OAM example

22. Conclusions from the article
Its simplicity and cost-effectiveness makes Ethernet a desirable technology for the NGN carrier networks
Can Ethernet still be considered ”simple” after the discussed changes???
Native Ethernet is lacking capabilities for MAN and WAN environment.

23. Conclusions from the article
PBB, PBB-TE and OAM aim to enhance Ethernet and provide the required carrier-grade services as from SONET/SDH, ATM and MPLS.
The competing carrier technologies OTN and IP/MPLS will be discussed latter in the course schedule!
Resiliency?
Work in progress!

24. For further leisure reading
Examples taken from “The road to Carrier-grade Ethernet” K. Fouli, M. Maier
Metro Ethernet Forum MEF