Offering Ethernet Services in Provider Networks

1
Offering Ethernet Services in Provider Networks

• Bijan Raahemi
• Research and Innovation Center
• Alcatel Canada

2
Outline

• Introduction
• Infrastructure
• Ethernet Services
• Metro Ethernet Network Solutions
• Provider Bridged Networks
• GMPLS-Enabled Metro Networks
• MPLS-Enabled Metro Networks
• VPLS, Providing Ethernet Connectivity over
  Provider Networks
• VPLS Model
• Scaling VPLS

3
Why Talking about ?

• Why Are We Talking about Services?
• Past Focus ? Infrastructure
• Todays Focus ? Revenue Generating Services
• Infrastructure Becoming commodity products (with
  Equipment vendors trying to minimize costs and
  maximize reliability)
• Services This is the area where companies
  (whether they're carriers or vendors) can really
  differentiate themselves Providing Service over
  (commodity) infrastructure. It is
  not a matter of transmitting bits and bytes any
  more!
• Why Are We Talking about Ethernet?
• More than 90 of desktop computers terminates on
  Ethernet networks
• It is a standard and low cost technology
• Proposals in MEF, IETF, and ITU to extend
  Ethernet in Metro
• 10G WAN PHY extends Ethernet into Wide Area
  Networks (Standard completed in 2002)

4
Ethernet Services Market
U.S Ethernet Services Forecast
4,000
VPLS
3,500
EIA
3,000
EPL
2,500
Revenue (USD Millions)
2,000
1,500
1,000
500
2007
2002
2006
2005
2004
2003
Source Yankee Group August 2003

• Ethernet Private Line (EPL) Point-to-Point
  CAGR 58.6
• Ethernet Internet Access (EIA) CAGR 102.4
• Ethernet Multipoint (VPLS) CAGR 134.2

5
Infrastructure

• Ethernet Over Dark Fiber
• Connecting Ethernet switches via dark fibers
• Easy and cheap
• Supports Ethernet Virtual Private Line, and
  Ethernet Virtual Private LAN service
• Drawbacks
• No OAM capability
• Cannot easily accommodate the dedicated switching
  bandwidth to individual subscribers (for Ethernet
  private lines)
• Ethernet Over SONET/SDH
• Ethernet frames are encapsulated into GFP frames,
  
• Mapped into a SONET channel using virtual
  concatenation,
• LCAS can be used to keep a connection running at
  a reduced rate if members of the virtual
  concatenation group fail, or add more members if
  the customer requests additional bandwidth.

6
Infrastructure (contd)

• Ethernet over ATM
• The IEEE 802.1Q (priority information) is mapped
  to the right ATM virtual circuit and service
  class.
• Allows a network operator to support Ethernet
  services with the end-to-end QOS and resiliency
  associated with ATM SLAs.
• It also provides flexibility in service topology,
  from point-to-point, to multipoint, with optional
  levels of oversubscription.
• Drawback Costly (for Greenfield deployment)
• Resilient Packet Ring (RPR), IEEE 802.17
• Supports a significant degree of bandwidth
  efficiency on rings through the implementation of
  bandwidth sharing, spatial reuse, and statistical
  multiplexing.
• Supports sub 50ms ring-based resiliency on packet
  switched network architectures.
• Can run over SONET/SDH or native Ethernet
  transport networks
• Ethernet Over IP/MPLS (we will talk more about
  this later in this presentation)
• Pseudowire
• VPLS

7
Whats Going on. in Industry?

• Most carriers have multiple Ethernet services
  delivery technologies.
• Most boxes in the network support them.
• Ethernet services can be supported by many
  network infrastructures
• ATM , IP/MPLS, SONET/SDH, WDM
• SONET/SDH equipment providers support Ethernet
  services using a mix of GFP, VCAT, LCAS, and RPR,
  leveraging the installed base of transmission
  equipment and its proven OAM and protection.
• Multi-service ATM switch vendors add Ethernet
  services blades to their products that can offer
  Ethernet-over-ATM Transparent LAN Service (TLS)
  with strict guaranteed QOS.
• Router vendors support a range of Ethernet VPNs
  over an IP backbone.
• A lot is happening, and much of it could have a
  significant influence on the telecom services.
• look at the recent issue of the IEEE
  Communication Magazine Ethernet WAN Transport
  (March 2004)
• LightReading Webinar Sponsored by Cisco Systems,
  Fujitsu, Metrobility Optical Systems, and
  RiverstoneNetworks, April 15, 2004 Metro
  Ethernet Services, What Customers Want?

8
Whats Going on. in Standards?

• Familiar Language
• Enterprises are used to Frame Relay services
• committed information rate (CIR), Excess
  information rate (EIR), etc.
• SLA (Service Level Agreement).
• Service Providers want to be able to talk to
  their customers in a familiar language.
• Interworking with other Layer 2 services, e.g.,
  Frame Relay or ATM.
• Different infrastructures are suited to different
  Ethernet service types
• The ITU-T is adapting Ethernet to SDH and MPLS
  transport networks.
• The IETF is emulating Ethernet links and LANs
  over a packet switched network.
• The IEEE is enhancing Ethernet capabilities such
  that services can be offered over pure Ethernet
  networks.
• The MEF is defining the service attributes and
  service parameters that enable a consistent set
  of features associated with various Ethernet
  services.
• Standardizations are working on multiple
  combinations of protocols.

9
Ethernet Service Components

• The MEFs basic model of Ethernet services is
  based on three key components
• The customer equipment (CE), either a switch
  (IEEE 802.1Q bridge) or a router.
• An Ethernet User Network Interface (UNI), based
  on a standard IEEE 802.3 Ethernet PHY and MAC,
  from 10 Mbit/s to 10 Gbit/s.
• The Metro Ethernet Network (MEN), which may use
  different transport and service delivery
  technologies, such as SONET/SDH, WDM, RPR,
  MAC-in-MAC, Q-in-Q (VLAN stacking), or MPLS.
• The MEN should be scalable and flexible
  enough to support a wide range of services in
  cost-effectIve manner (comparable to TDM, Frame
  Relay, or ATM)

Metro Ethernet Forum (MEF) http//www.metroetherne
tforum.org
10
Ethernet Service Types

• Ethernet Line (E-Line)
• point-to-point connectivity
• E-line services can be used to create Ethernet
  private line services, Ethernet-based Internet
  access services, and point-to-point Ethernet
  VPNs.

• Ethernet LAN (E-LAN)
• multipoint-to-multipoint (any-to-any)
  connectivity.
• E-LAN Services can be used to create multipoint
  Ethernet VPNs, and Ethernet Transparent LAN
  services.

Carrier Networks
UNI
UNI
Metro Ethernet Network
Customer Equipment
EVC1
Customer Equipment
Customer Equipment
Customer Equipment
EVC3
UNI
UNI
Point-to-Point EVC
EVC2
UNI
Ethernet Learning Bridge
Customer Equipment
Metro Ethernet Forum (MEF) http//www.metroethern
etforum.org
11
Ethernet Services Examples from Metro Ethernet
Forum
EtherRelay service using E-Line Service type
Ethernet Private Line to ASP for storage
application
LAN Extension application using E-LAN service
type
Intranet/Extranet application using E-Line
service type
12
Outline

• Introduction
• Infrastructure
• Ethernet Services
• Metro Ethernet Network Solutions
• Provider Bridged Networks
• GMPLS-Enabled Metro Networks
• MPLS-Enabled Metro Networks
• VPLS, Providing Ethernet Connectivity over
  Provider Networks
• VPLS Model
• Scaling VPLS

13
Solution 1 Provider Bridged Network
VLAn ID (12 bits)
.1p (3 bits)
CFI (1 bit)
CRC
MAC DA
MAC SA
VLAN Tag
Orig. EthTyp
Data
.1Q P-VLAN tag
Eth Type 0x8100
.1Q Eth Type
Frame Format
Metro Ethernet Network
CES
CES
PE-A
UNI-A
PE-B
UNI-B
CE-A
CE-B
CES
PE-C
CE Customer Equipment PE Provider Edge
Bridge/Router UNI User to Network Interface CES
Core Ethernet Switch/Bridge
Spanning Tree
UNI-C
CE-C
14
Ethernet is Evolving..Carrier Class Ethernet

• Challenges with a Pure Ethernet Solution?
• Ethernet was originally developed for the LAN
  applications (shared medium), providing best
  effort access.
• It uses flat addressing (scalability).
• It lacks traffic engineering (load balancing)
• It lacks rich OAM (Operation, Administration,
  Maintenance) features.
• Its spanning tree protocol converges slowly.
• It lacks Quality of Service (QoS).
• Solution in Progress
• Scalability IEEE 802.1ad work on Q-in-Q
• Fast Convergence of Spanning Tree IEEE 802.1w
  work on Rapid Spanning Tree
• OAM is being standardized (IEEE Ethernet in the
  First Mile) to monitor link operation, and
  improve fault isolation
• MEF is specifying architecture, protocols and
  management for metro Ethernet. This will result
  in specifications for EVC protection, QOS, an
  Ethernet NNI, and OAMP for end-to-end management
  of Ethernet services, regardless of the
  underlying transport technology.
• Class of Service Various solutions are being
  proposed for this shortcoming. Ethernet classes
  of service (COS) can be identified via IEEE
  802.1Q, user priority bits (802.1p), MPLS EXP
  bits, or DiffServ Codepoints,
• IEEE 802.3ad (Link Aggregation) Faster
  connections between switches managed as a single
  connection, load balancing among the individual
  links within a logical connection For the service
  providers, a final value is the ability to add or
  subtract bandwidth to a connection in whatever
  combination of bandwidths (10 Mbit/s, 100 Mbit/s,
  1 Gbit/s) is available on that switch.

15
Ethernet Bridging Technology is EvolvingBut is
it Enough?
1997 Enterprise Bridging
2000Metro-Oriented Extensions
2004Bridging Technology Futures

• VLANs
• 802.1D Spanning Tree
• Per-port RMON statistics
• Ping and Traceroute

• VLANs
• 802.1D Spanning Tree
• Per-port RMON statistics
• Ping and Traceroute
• 802.3ad link aggregation
• 802.1P/DiffServ
• 802.1w RSTP
• 802.1s MIST
• VLAN stacking
• Ring Spanning Tree

• VLANs
• 802.1D Spanning Tree
• Per-port RMON statistics
• Ping and Traceroute
• 802.3ad link aggregation
• 802.1P/DiffServ
• 802.1w RSTP
• 802.1s MIST
• VLAN stacking
• Ring Spanning Tree
• EFM
• 802.1ad provider bridges

Ethernet Bridging is trying to adapt.
16
Solution 2 GMPLS-Enabled Metro Network

• Just a potential solution.
• Not all the details are worked out yet.
• How it works
• Core nodes are simple Ethernet switches
• (Electrical counterpart of Optical switch)
• No need to run a spanning tree protocol.
• A new label (such as MAC address) is added to
• the packet at Ingress.
• A forwarding table is maintained at each core
  
• switch.
• Packets are forwarded in the MEN based on the
• outer label.
• This network solution is capable of providing
• many features such as traffic engineering,
• Quality of service, path protection, fault
• recovery, and OAM functionalities.
• Challenges

17
Solution 3 MPLS-Enabled Metro Network
VC Label
Tunnel Label
MAC DA
MAC SA
VLAN Tag
Eth Type
CRC
Data
Frame Format (Martini Encap)
18
The Advantages of an MPLS-Enabled Metro
EthernetDeterministic, Scalable, Resilient
Networks and Services

• Support for tens of 1000s of subscribers
• Robust, manageable control plane protocols
• Enables inter-metro services
• Fast failover for services
• Per-service QoS
• Sophisticated billing models

• Leverages MPLS switching
• No Spanning Tree Protocol
• No VLANs or Q-tag management
• End-to-end OAM tools
• Traffic Engineering for efficient use of network
  resources
• Sophisticated SLAs

19
Outline

• Introduction
• Infrastructure
• Ethernet Services
• Metro Ethernet Network Solutions
• Provider Bridged Networks
• GMPLS-Enabled Metro Networks
• MPLS-Enabled Metro Networks
• VPLS, Providing Ethernet Connectivity over
  Provider Networks
• VPLS Model
• Scaling VPLS

20
VPLS

• VPLS is a network service that offers layer 2
  multipoint connectivity between edge devices in a
  single bridge domain.
• VPLS transforms the packet network into a
  switched LAN. To the enterprise, the VPLS service
  makes the service provider network operate as a
  single VLAN, with a unique SLA, protection
  attributes, availability attributes and MAC
  address learning and forwarding for scalable
  multipoint configurations.

All customer sites using VPLS appear to be on the
same LAN, regardless of their locations. Customer
edge devices appear to each other as connected
via single logical learning bridge with fully
meshed ports.
21
VPLS Model

• CE may be a router, a switch, or a host.
• PE is a router which includes a "bridge"
  module. At minimum, the "bridge" module
• must perform MAC addresses learning, and
  aging.
• Attachment Circuit may be a Frame Relay DLCI,
  an ATM VPI/VCI, an Ethernet
• port, a VLAN, a PPP connection, an MPLS LSP,
  etc.
• A Pseudo Wire is a connection between two PE
  devices.
• MTUs are typically located in large buildings,
  serving different customers.
• In the IETF PPVPN terminology, an MTU is called
  a Layer2 PE (L2PE).

Site A
Site B
CE
PE
Service Provider Network
PE
P
CE
P
Attachment Circuit
Site C
PE
CE
Layer 2 Link
LSP Tunnel
Pseudo Wire
MTU/L2PE
VPLS A
Site D
CE Customer Edge Device PE Provider Edge
Device P Provider Router MTU Multi Tenant
Unit
CE
22
VPLS Building Blocks

• Network Elements
• the transport layer, as well as switches and
  routers.
• Tunneling
• encapsulation of a data packet into payload of
  another data packet.
• Signaling
• (also called auto-configuration) the mechanism
  by which tunnels are established, and routing
• information are exchanged.
• VPLS edge device discovery
• (also called Auto-discovery function) the
  process by which one PE router learns which other
  PE
• routers are participating in the VPLS.
• MAC address learning
• the PE learns the source MAC addresses of the
  devices in the network and keeps them in a
• separate forwarding information base (FIB) for
  every VPLS.
• Flooding
• this function is used by the routers to learn
  unknown MAC addresses.
• Loop avoidance

23
VPLS OptionsLasserre-V.Kompella (LDP) vs.
K.Kompella (BGP)

• The Lassere-V.Kompella draft uses LDP for
  pseudowire signaling a point-to-point signaling
  already used in Draft Martini.
• LDP is point-to-point signaling protocol. It
  establishes the connections one by one.
• The Lassere-V.Kompella draft does not define an
  auto-discovery method (so there is a need for
  extension of LDP, or to do it manually, or to
  develop proprietary solutions)
• The Lassere-V.Kompella draft is supported by many
  vendors including Alcatel.
• The K.Kompella draft uses BGP protocol for both
  signaling and auto-discovery.
• BGP is a broadcast signaling protocol. Every time
  it sets up a new connection, it uses route
  reflector to broadcast messages to every PE
  router.
• Since BGP is already being used for signaling and
  discovery in Layer 3 VPN, it can be re-used for
  VPLS as well.
• However, since BGP is a broadcast protocol, it
  may not be bandwidth efficient.
• The K.Kompella draft is mainly supported by
  Juniper.

24
Scaling VPLS
If all MTU devices are full-blown VPLS PE
devices, then as the number of customer grows,
there will be a significant increase in -
The number of tunnels (every PE needs to
maintain one tunnel to every peer PE) - The
number of Pseudo Wires (every PE needs to
maintain one PW per VPLS per every peer PE) -
The total number of MAC addresses per PE -
The number of signaling connections
PE
PE
PE
PE
PE
25
Hierarchical VPLS (Hub-and-Spoke)
Hierarchical VPLS distributes the VPLS functions
between PE devices and MTUs. It reduces the
replication requirement (data plane) and the
number of signaling connections (control
plane). However, it does not reduce the number of
MAC addresses that need to be maintained. PE
still does the Ethernet bridging.
Spoke VC Can be MPLS (draft Martini) or VLAN Tag
(Q-in-Q)
MTU
MTU
PE
PE
MTU
PE
MTU
MTU
Hub
26
H-VPLS Reduces Replication
Hierarchical VPLS reduces the replication
requirement when the full mesh of pseudo wires
grows.
Hierarchal VPLS
Basic VPLS
27
H-VPLS Facilitates Provisioning Signaling
Hierarchical VPLS facilitates provisioning and
signaling when a new site is added to the
network.
Hierarchal VPLS
Basic VPLS
New site
New site
MTU
PE
MTU
MTU
PE
PE
PE
PE
PE
MTU
PE
MTU
MTU
PE
PE
28
De-Coupled VPLS

• De-coupled VPLS distributes the VPLS functions
  between PEs and MTUs.
• De-coupled VPLS reduces the number of MAC
  addresses to maintain, and the number of
  signaling connections, but does not limit the
  number of Pseudo-Wires as the Hierarchal VPLS
  does.
• All Ethernet MAC functions (MAC switching,
  learning, aging, flooding, STP, etc) and
  Pseudo-Wire termination functions are performed
  in the MTU, while the auto-discovery and the LSR
  (MPLS) functions are performed in the PE.

29
De-coupled VPLS, how it works?

• All sites attached to MTU A, B, and C belong
  to one VPLS (orange).
• The link between MTU and PE is able to
  maintain multiple virtual circuits,
• implemented using MPLS labels or VLAN tags.
• PE acts as an LSR/LER. It does not implement
  Ethernet bridging functions.
• Each MTU needs to establish and maintain one
  Pseudo-Wire to every other MTU
• associated with that particular VPLS.

De-coupled VPLS
Signaling
Signaling
30
De-coupled VPLS how it addresses scalability?

• MTUs (L2PEs) have only one signaling connection.
• PEs are MPLS routers, and act as forwarding
  engine. They do not provide Ethernet bridging
  functions.
• Number of core signaling connections for PE
  devices does not depend on the number of L2PE
  (MTU) devices. It depends only on the number of
  PEs.
• However, the number of Pseudo-Wires is highly
  dependent on the number of L2PEs participating in
  a particular VPLS.
• Also, addition of a new L2PE (MTU) into an
  existing VPLS will trigger the provisioning of a
  new Pseudo-Wire in every MTU that belongs to that
  VPLS.
• When an MTU receives an unknown unicast or a
  multicast frame from a CE, it needs to broadcast
  the frame on every Pseudo-Wire to every peer MTU.

31
Summary

• There is a lot going on both in industry and in
  standardization to define and support Ethernet
  services in the MAN.
• Ethernet is evolving into a reliable, scalable,
  and manageable transport technology
  (opportunities for innovation and new solutions)
• Presented different solutions to support Carrier
  Class Ethernet Services in the MAN.
• MPLS-Enabled Metro Ethernet is the feasible
  solution available today.

32
Thank You www.alcatel.com