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Metro Ethernet: Understanding Key Underlying Technologies © Copyright 2007 All Rights Reserved Metanoia, Inc. +1-888-641-0082.

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Presentation on theme: "Metro Ethernet: Understanding Key Underlying Technologies © Copyright 2007 All Rights Reserved Metanoia, Inc. +1-888-641-0082."— Presentation transcript:

1 Metro Ethernet: Understanding Key Underlying Technologies © Copyright 2007 All Rights Reserved Metanoia, Inc Metanoia, Inc. Critical Systems Thinking

2 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 2 Who is Metanoia, Inc.? Specialty technology consultancy founded in mid-2001, with HQ in Mountain View, California Undertakes deep-dive technical consulting in telecom network, systems, software and chip architecture and design for clients across the world Services have spanned 4 continents, with clients in: North America, Europe, Asia, and Australia. Principals provided services in technology strategies, architecture and design trade-offs, product development, hardware/software architecture, and knowledge enhancement to organizations that include large equipment manufacturers, international, national and regional ISPs, premier metro/access systems startups, network planning tool vendors, established software and technology houses and leading component and semiconductor vendors Principals are technologists at the forefront of new developments, as leaders, creators, implementers, researchers, academics, strategists, and advisors in the US and abroad Expertise spans Layer 1 through Layer 4, and wireline (optical, Ethernet, IP/ATM, SONET/SDH) through wireless (Wi-Fi, cross-layer design, Wi-Max, cellular data, 2.5-3G) 125+ man years of technology design and development, and technology management experience, having worked at leading global corporations, such as Apple, AOL Time Warner, BBN, Cisco, 3Com, Fujitsu, LSI Logic, Motorola, Tellabs, Siemens, Nokia, Tibco, and Qualcomm, and having worked at/consulted to corporates in the US and abroad for almost the last decade 70+ patents collectively issued/pending Advanced graduate degrees from some of the most distinguished universities in the world – the University of California, Stanford University, Iowa State University, the University of Texas, the University of Waterloo, and the Indian Institute of Technology

3 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 3 Workshop Outline Legacy networks & Ethernet over legacy networks Value propositions and business drivers Ethernet over SDH/SONET Metro Ethernet Forum (MEF) MEF architecture E-Line and E-LAN services Native Ethernet as Carrier-class transport Provider Bridges Provider Backbone Bridges (PBB), Provider Backbone Transport (PBT) MPLS – an enabler for Ethernet services Layer 2 VPNs: VPWS, VPLS, H-VPLS Advanced concepts: traffic engineering, QoS, OAM, resilience Conclusions

4 Ethernet over Legacy Networks Metanoia, Inc. Critical Systems Thinking

5 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 5 Issues with Legacy Networks Low bandwidth No flexibility to scale High cost of installation Slow provisioning Bandwidth growth inflexible/non-linear Limited by multiplexing hierarchy TDM-based access: inefficient for converged data

6 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 66 Next-Generation SDH NG ADM Ethernet Central Office Switch Core Network Customer Network STM/4/16 Ring Cross Connect TDM Ckt Customer Network NG-SDH Customer Network Customer Network

7 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 7 Ethernet-over-SDH Framing protocol Encapsulates Ethernet frames in SDH payloads Mapping of SDH payload to SDH channels Virtual concat.: for allocation of non-contiguous VCs Flow control mechanism Avoids packet drops due to speed mismatch between SDH and Ethernet Mechanism to increase/decrease allocated SDH bandwidth Add or remove VCs

8 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 8 Ethernet-over-SDH (contd) Very popular in carriers with installed base of SDH rings E.g. BSNL in India Good deployment choice when traffic primarily circuit switched Inefficient if major traffic is bursty packet-switched data Solution: Carrier-class Ethernet!

9 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 9 Metro Ethernet Value Propositions Lower per-user provisioning costs Technically simple relative to TDM ckts. Due to large installed base Efficient and flexible transport Wide range of speeds: 128 Kbps--10 Gbps QoS capabilities Ease of inter-working Plug-and-play feature Ubiquitous adoption The technology of choice in enterprise networks

10 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 10 Ethernet Business Drivers Business connectivity Storage networks Data centers Video conferencing Residential services Triple-play services (IPTV) On-line gaming High-speed Internet access Wireless backhaul Reduced cost, complexity for mobile operators

11 Metro Ethernet Services Metanoia, Inc. Critical Systems Thinking

12 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 12 Metro Ethernet Forum (MEF) Industry forum at forefront of Carrier Ethernet standardization Carrier Ethernet architecture Ethernet services Founded in Currently approx. 120 members Technical Sub-committees Architecture Services Protocols and Transport Management

13 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 13 MEN Architectural Components 13 End User Customer Network MEN Customer Network End User S T T S UNI Reference Point Ethernet Virtual Connection End-to-End Ethernet Flow End user Interface Ethernet Flow Unidirectional stream of Ethernet frames UNI Interface used to interconnect MEN subscriber to provider EVC Defines association between UNI for delivering Ethernet flow across MEN

14 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 14 Application Service Layer (IP, MPLS, PDH, E1/E3, SDH) Ethernet Service Layer Transport Service Layer (802.1, SONET/SDH, MPLS) MEN Layer Model

15 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 15 MEF Services Definition Framework Service Type Construct used to create broad range of services Service Attributes Defines characteristics of a service type Attribute Parameters Set of parameters with various options

16 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 16 Service Types E-Line Point-to-point Ethernet Virtual Circuit (EVC) E-LAN Multipoint-to-multipoint Ethernet Virtual Circuit 16 EVC 1 EVC 2

17 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 17 Service Attributes Physical Interface Medium, speed, mode, MAC layer Traffic Parameters CIR, CBS, PIR, MBS QoS Parameters Availability, delay, jitter, loss Service Multiplexing Multiple instances of EVCs on a given physical I/F Bundling Multiple VLAN IDs (VID) mapped to single EVC at UNI

18 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 18 Ethernet Services Ethernet Private Line (EPL) Uses E-Line Does not allow service multiplexing High degree of transparency Low delay, delay variation, and packet loss ratio Ethernet Virtual Private Line (EVPL) Uses E-Line Allows for service multiplexing Need not provide full transparency

19 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 19 Service Types and Ethernet Services Ethernet Services

20 Native Ethernet as Carrier-class Transport Metanoia, Inc. Critical Systems Thinking

21 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 21 Requirements for Carrier-class Ethernet Scalability Network should support millions of subscribers Protection and restoration 50ms resilience Quality-of-Service (QoS) Ability to offer differentiated levels of service Service Monitoring and Fault Management Support for TDM traffic Seamless integration with legacy networks

22 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 22 Ethernet Ring Ethernet Switch Ethernet Switch Ethernet Switch Ethernet Switch 1/10 Gigabit Ethernet Ring Core Network Customer Network Customer Network

23 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 23 Native Ethernet in Metro Access How does one create the notion of a virtual circuit? VLAN tagging with point-to-point VLAN VLAN stacking Outer tag service instance; Inner tag individual customer 802.1Q in 802.1Q (Q-in-Q) - IEEE 802.1ad C-DA: Customer Destination MAC C-SA: Customer Source MAC C-TAG: IEEE 802.1q VLAN Tag C-FCS: Customer FCS S-TAG: IEEE 802.1ad S-VLAN Tag C-DAC-TAGC-SA Client data FCS S-TAG 6bytes 4bytes

24 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 24 Customer Network Customer Network Customer Network 24 Provider Bridge (IEEE 802.1ad) Architecture CE: Customer Equipment UNI: User-to-Network Interface CES: Core Ethernet Switch/Bridge P-VLAN: Provider VLAN UNI-B CES CE-A UNI-A UNI-C CE-C Spanning tree CE-B CES

25 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 25 Limitations of Provider Bridge Scalability Limited to 4096 service instances Core switches must all MAC addresses Broadcast storms ensue due to learning MAC address tables explode!

26 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 26 Provider Backbone Bridging (802.1ah) Encapsulate customer MAC with provider MAC at edge Edge switch adds 24-bit service tag (I-SID), not VLAN tag Core switches need only learn edge switch MAC adds. S-TAG: IEEE 802.1ad S-VLAN Tag B-DA: IEEE 802.1ah Backbone Destination B-SA: IEEE 802.1ah Backbone Source MAC I-TAG: IEEE 802.1ah Service Tag B-DA B-TAGB-SA I-TAG C-DAC-TAGC-SA Client data B-FCS 6bytes 4bytes5bytes4bytes

27 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 27 Provider Backbone Bridging (PBB) Architecture CPE B CPE A CPE C Provider backbone network (802.1ah) CPE B CPE A 802.1ad CPE B 802.1q CPE C Provider backbone network (802.1ad) CPE D CPE C CPE A Provider backbone network (802.1ad) Provider backbone network (802.1ad) Provider backbone network (802.1ad)

28 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 28 Benefits of PBB Scalability Addresses limitations of 4096 service instances Robustness Isolates provider network from broadcast storms Security Provider need switch frames only on provider addresses Simplicity Provider & customers can plan networks independently

29 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 29 Traffic Engineering in PBB Via Multiple Spanning Tree Protocol (MSTP) Maps a VLAN to ST or multiple VLANs to ST Enables use of links that would otherwise be idle in ST Eliminates wasted bandwidth … but … Too slow for protection switching Not suitable for complex mesh topologies Difficult to predict QoS

30 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 30 Challenges with an All-Ethernet Metro Service Restriction on # of customers – 4096 VLANs! Service monitoring Scaling of Layer 2 backbone Service provisioning Carrying a VLAN is not a simple task! Inter-working with legacy deployments Need hybrid architectures … Multiple L2 domains connected via IP/MPLS backbone

31 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 31 What Solutions do we Have? Ethernet-based Architecture Provider Bridge (802.1ad) in edge Provider Backbone Transport (PBT) in Core Hybrid Architecture 802.1ad in the edge Multiprotocol Label Switching (MPLS) in core

32 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 32 Provider Backbone Transport (PBT) Connection-oriented, traffic-engineered Ethernet tunnels Replaces spanning tree control plane with either a: Management plane External control plane No learning ! Forwarding info. provided by management plane Forwarding done on MAC + VID (60-bit) address VID is not network global; however, MAC + VID is B-MAC identifies destination B-VID identifies per-destination alternate paths

33 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 33 Customer Network Customer Network 33 PBT Architecture Central TE Module SA : PE1 DA : PE2 VLAN 22 SA : PE1 DA : PE2 VLAN 33 PE1 PE2

34 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 34 Benefits of PBT No learning Eliminates undesirable broadcast storms Resolves MAC flooding problem Addresses scaling by forwarding on MAC + VID-highly scalable Protection Sets-up backup paths 50ms restoration possible QoS support available

35 MPLS – An Enabler for Ethernet Services: Fundamentals & Operations Metanoia, Inc. Critical Systems Thinking

36 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 36 Basic Concept of MPLS Routing fills routing table Signaling fills label forwarding table x x.x Advertises binding Advertises binding x x.x 72 Advertises bindings x x.x X X Routing Table Label Table R1R2 R3 R4

37 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 37 Basic Concept of MPLS x x.x x x.x x x.x X X 3 5 Packet arrives DA= Push Label 5 Pop label Forward packet Swap Label R2R1 R3 R4

38 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 38 So what about MPLS Control and Forwarding? Superset of conventional router control Distribute info. via n/w layer routing protocols (OSPF, BGP, etc.) Algos. to convert routing info. into forwarding table: Create binding from FEC label Assign & distribute labels to peer LSRs via signaling Label switching forwarding table (or label information base LIB) Forwarding algo = label swapping, independent of control component (implementable in optimized H/W or S/W) Control Component Forwarding Component First Subentry Second Subentry (for multicast or load balancing) Incoming Label Map Next hop label forwarding entry (NHFLE) Outgoing label Outgoing inf. Next hop address Outgoing label Outgoing inf. Next hop address Incoming Label

39 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 39 What does a Label Represent? The Issue of Label Granularity Packets form Forwarding Equivalence Class (FEC) Treated identically by participating routers Assigned the same label Membership in FEC must be determinable from IP header + other info. that ingress router has about the packet Entities that may be grouped into an FEC are flexible. E.g. FEC could be: Connection between two IP ports on two hosts or between IP hosts Traffic headed for a particular network with same TOS bits All destination networks with a certain prefix Manually configured connection Traffic belonging to a customer or department VLAN Traffic of a given application – voice, video, plain data, management traffic … and many others

40 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 40 Lets Recap: Elements of MPLS Label Forwarding Use data link addressing. E.g. ATM VPI/VCI, FR DLCI Shim header between data link and IP header Label Creation and Binding Label Assignment and Distribution Ride piggyback on routing protocols, where possible (BGP) Separate label distribution protocol – RSVP, LDP Data Plane Control Plane 1 bit

41 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 41 Primary Label Assignment and Distribution Modes Edge LSR Downstream-on-demand with Independent Control 1Requests 2 2Assignments Edge LSR Downstream-on-demand with Ordered Control 1Requests 4 Assignments

42 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 42 Advantages of MPLS Original justification Availability of fast, amortized, ATM hardware; emergence of H/W forwarding engines has practically eliminated this Current justifications Separates forwarding from control, allowing Routing functionality to evolve independently of forwarding algorithm MPLS to control non-packet technologies: SONET/SDH ckts., lightpaths Provides explicit, manageable IP routes Enables policy routing and traffic engineering Offers TE for Ethernet tunnels in metro-Ethernet environments Facilitates scalable hierarchical routing

43 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 43 The Utility of Hierarchical Label Switching Core LSRs Edge LSRs Swap and Push Pop Swap Concept is similar to VLAN stacking in PBT we saw earlier

44 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 44 Hierarchical Label Stacking/Switching Inside a transit AS, each core router must keep track of all networks that might be reached through it With hierarchical labels, only edge routers need know what networks might eventually be reached through them All transit traffic can be made to tunnel through core routers using LSPs with stacked labels

45 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 45 Explicit Manageable Routes -- Policy routing, Traffic engineering Carriers want certain traffic to go over certain routes. Such network engineering: Keeps network loads balanced Enhances network stability and reliability Enables better QoS and performance assurances Allows carriers to meet customer SLAs Constraint-based routing together with MPLS allows carriers to Bind Ethernet tunnels to an LSP, Place (or route) LSP over the desired sequence of LSRs in the n/w TE tunnels are helpful for VPLS-based carrier Ethernet n/ws

46 IP/MPLS-based Layer 2 VPNs Metanoia, Inc. Critical Systems Thinking

47 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 47 L2 VPN Components What does the P1-PE2 connection really look like?

48 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 48 L2 VPN Component Details

49 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 49 VPLS Network Overview

50 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 50 VPLS Protocols Involved

51 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 51 Operational Characteristics of VPLS

52 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 52 Data Plane: Flooding, Address Learning and Forwarding All address unknown frames (unicast, multicast, broadcast) flooded over corresponding PWs to all relevant PEs only

53 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 53 Address Learning Layer 2 reachability directly learned in data plane Use standard learning bridge functions for local MACs PW-based association for remote MACs Allow PE to determine from which physical port or LSP a given MAC address came VSI FIB keeps mapping between Ethernet MAC PW to use Qualified LearningUnqualified Learning - Each customer VLAN is its own VPLS instance - Has its own PW mesh and brdcast domain - All customer VLANs are part of the same VPLS - One PW mesh and single brdcast domain

54 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 54 Address Learning Example

55 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 55 Forwarding and Encapsulation Forwarding requires ability to Dynamically learn MAC addresses on Physical ports Pseudowire VCs (VC LSPs) Forward/replicate pkts. across physical ports and VC LSPs Encapsulation PW header applied to Ethernet packet w/o preamble + FCS VLAN tag denoting customers VPLS instance can be stripped at ingress, reapplied at egress

56 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 56 Tunnel and PW Topology and Loop Freedom Full mesh of PW and tunnels deployed Tunnels Help transport the PW payload Aggregate traffic from multiple PWs Pseudowires – demultiplex the L2 traffic traversing tunnels

57 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 57 Scaling VPLS: Hierarchical VPLS Base VPLS requires full mesh of VC LSPs between PE routers Adequate for PE routers in CO – multiple customers aggregated Inadequate for PE routers in MTU basements!

58 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 58 Hierarchical VPLS Advantages Benefits Simplifies signaling Reduces pkt. replication Simplifies MTU Scalable inter-domain VPLS Simplifies new site addition

59 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 59 Hierarchical VPLS: Case Study for a Metro Region 100 MTUs; 10 customers/MTU; 2 VPLS/cust.; 100 stations/VPLS VPLSs/MTU = 10x2 = 20 MACs/MTU = 20x100 = 2000 No hierarchy PE supports 2000 MACs LDP/BGP sessions = (100x99)/2 x 20 = 245,000 Hierarchy (10 MTU/PE) PE supports 2000 x 10 = 20,000 MACs LDP/BGP sessions = (10x9)/2 x 200 = 9000 # of spoke VLLs = 10 x 20 = 200

60 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 60 Benefits of IP/MPLS-based L2 VPNs Separation of administrative responsibilities Migration from traditional L2 VPNs: seamless transport of Ethernet services Privacy of routing Layer 3 independence Less operational overhead Ease of configuration (?)

61 Advanced Features: Traffic Engineering, Resilience, OAM, QoS Metanoia, Inc. Critical Systems Thinking

62 Traffic Engineering Concepts © Copyright 2006 All Rights Reserved Metanoia, Inc. Critical Systems Thinking

63 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 63 Constraint Based Routing A class of routing systems that computes routes through a network subject to a set of constraints and requirements QoS-based Routing Path of flows determined by Knowledge of resource availability in network QoS requirements of flows Policy-based Routing Path/routing decision based on administrative policy Can be on-line or off-line

64 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 64 CB Routing System Inputs Flow/path attributes: required b/w, hop count,... Resource attributes: properties of nodes/links Network topology & state Outputs Computed feasible path Explicit route of the path

65 MPLS-based Resilience for the Metro © Copyright 2006 All Rights Reserved Metanoia, Inc. Critical Systems Thinking

66 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 66 Fundamental Characteristics of RSVP Allows apps. to signal QoS requests to n/w, and n/w to respond with success or failure Designed to transport Classification info. (Sender_Template) Allows flows with specific QoS reqs. to be recognized Traffic specs of source/sender (Tspec) QoS needs of receivers (Rspec) Soft-state protocol Path/Resv transmitted periodically to refresh reservation Refresh Reduction [RFC2961] has practically eliminated original scalability concerns with use of soft state

67 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 67 Basic Operation of RSVP-TE

68 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 68 Fast Re-Route (FRR) using RSVP-TE Rerouting is done when A better path is available Upon failure along LSP Use SESSION Obj. & SE style Tunnel uniquely identified by Destination IP address Tunnel ID Ingress IP address Tunnel ingress made to appear as 2 different senders to the RSVP session (via LSP ID)

69 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 69 TE with Constraint-based Routing in a Nutshell

70 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 70 How it All Fits Together

71 OAM: The Traditional Achilles Heel of Ethernet © Copyright 2006 All Rights Reserved Metanoia, Inc. Critical Systems Thinking

72 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 72 Why Ethernet OAM? Current management protocols lack per-customer granularity to handle Ethernet services Most management protocols operate are point-to-point Ethernet OAM can exploit multipoint capability Link management required for last-mile connection Similar to link mgt. in FR and ATM

73 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 73 Ethernet OAM Types Service OAM e2e connectivity and fault mgt. per service instance Part of IEEE 802.1ag, CFM project Link OAM Monitoring & fault mgt of individual Ethernet link (physical/emulated) Part of IEEE 802.3, Clause 57 (formerly 802.3ah (not to be confused with 802.1ah)) Ethernet Local Mgt. Interface (E-LMI) Configuration & operational provisioning of customer edge device Part of MEF Standard MEF-16

74 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 74 Service OAM Works on per-EVC basis Independent of underlying transport technology CFM messages Continuity Check Message Detects loss of service connectivity Link Trace Message Traces the path hop-by-hop (like IP traceroute) Loopback Message Detects whether target point is reachable (like ICMP Ping) AIS (Alarm Indication Signal) Message Asynchronous notification to indicate fault

75 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 75 Link OAM Discovery Identifies devices at both ends of the link Link Monitoring Detects link faults Statistics of packet errors Remote Failure Indication Conveys loss-of-signal indication to peers, due to poor SNR, power failure, or other critical events Remote Loopback Determines quality of link during installation and troubleshooting

76 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 76 E-LMI Provides local configuration & operational parameters to customer edge VLAN-EVC mapping QoS profiles of EVC Reduces configuration errors, improves performance Dynamic EVC management

77 Quality-of-Service: Ah! that elusive QoS © Copyright 2006 All Rights Reserved Metanoia, Inc. Critical Systems Thinking

78 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 78 MPLS and Quality-of-Service for Ethernet Services MPLS supports (not extends) a packet-based QoS model MPLS does not run in hosts (only in metro/core routers) QoS, however, is an end-to-end mechanism MPLS helps carriers offer QoS-enabled services efficiently Can support MEF QoS model via DiffServ QoS framework

79 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 79 Differentiated Services Framework Traffic flows aggregated into small # of classes Per-flow state is not required More scalable than IntServ EF AF1x AF2x AF3x AF4x Priority Drop Precedence Class DSCP 001xx0 01xx10 1xxx10 11xx Class encoded in IP header via DiffServ Code Point (DSCP) Edge router … Classifies packets to DifServ classes DSCP identifies Per Hop Behavior (PHB) Best Effort (BE) Expedited Forwarding (EF) Minimal delay & loss Assured Forwarding (AF) 4 classes 3 drop precedences each 12 possibilities total BE

80 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 80 Differentiated Services Architecture Colored packet (marked DSCP)

81 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 81 MPLS Support of DiffServ: Mapping DSCPs to LSPs (or labels) Map DSCP EXP bits in MPLS shim header 6 DS bits (64 PHBs) and only 3 EXP bits (8 classes)! Complete mapping is infeasible For many practical cases, 8 PHBs may suffice Results in an LSP called an E-LSP Label EXP TTL S DSCP 6 bits IP Header DSCP 3 bits DS byte MPLS shim header

82 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 82 MPLS Support of DiffServ: Mapping DSCPs to LSPs (or labels) Map {PHB, FEC} MPLS Label That is, provide the info. in the label itself! Requires enhancing the label distribution protocols Use EXP bits for drop precedence That is to determine different PHBs of a PHB scheduling class Label EXP TTL S DSCP 6 bits DSCP 3 bits DS byte DS class drop precedence DS class: EF, AFx IP Header MPLS shim header Results in an LSP called an L-LSP

83 Conclusions and Discussion Metanoia, Inc. Critical Systems Thinking

84 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 84 Conclusions Ethernet poised to be dominant choice in metro networks Reduces capex and opex for providers Enables new revenue generating services 802.1ad provider bridge with OAM of 802.1ag … … a choice at the edge Two architectures emerging for Ethernet in the metro core Provider Backbone Transport (PBT) IP/MPLS-based L2 VPNs

85 Thank You! Questions? Metanoia, Inc. Critical Systems Thinking

86 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 86 Glossary ACAttachment Circuit ACLAccess Control List AFAssured Forwarding APIApplication Programming Interface ASAutonomous System ATMAsynchronous Transfer Mode BABehavior Aggregate B-DABackbone Destination Address B-DABackbone Source Address BEBest Effort B-FCSBackbone Frame Check Sequence BGPBorder Gateway Protocol CBSCommitted Burst Size CECustomer Edge (router) CESCore Ethernet Switch/Bridge CFM CIRCommitted Information Rate COCentral Office DADestination Address DSDiffServ DSDiffServ DSCPDiffServ Code Point EFExpedited Forwarding E-LMIEthernet-Local Management Interface E-LSPEXP mapped LSP EPLEthernet Private Line EROExplicit Route Object E-UNIEthernet UNI EVCEthernet Virtual Circuit EVPLEthernet Virtual Private Line EXP Experimental (EXP bits in MPLS "shim" header) EXPExperimental Bits FCSFrame Check Sequence FECForwarding Equivalence Class FIBForwarding Information Base FRFrame Relay GRGraceful Restart H-QoSHierarchical Quality-of-Service H-VPLSHierarchical VPLS IPTVIP Television

87 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 87 Glossary L2Layer 2 (Data Link Layer; MAC Layer) L3Layer 3 (Network or IP Layer) LANLocal Area Network LDPLabel Distribution Protocol LERLabel Edge Router LIBLabel Information Base L-LSPLabel inferred LSP LSPLabel Switched Path LSRLabel Switching Router MACMedium Access Control MBSMaximum Burst Size MEFMetro Ethernet Forum MENMetro Ethernet Architecture MPLSMulti-Protocol Label Switching MSTPMultiple Shortest Path Tree MTUMulti-Tenant Unit NGNext Generation NGNNext-Generation Network NNINetwork Network Interface OAMOperations, Administration, and Management OSPFOpen Shortest Path First PProvider (router) PBProvider Bridging PBBProvider Backbone Bridging PBTProvider Backbone Transport PDHPleisosynchronous Digital Hierarchy PEProvider Edge (router) PHBPer Hop Behavior PIRPeak Information Rate PSNPacket Switching Network P-VLANProvider VLAN PWPseudo-Wire QoSQuality-of-Service RIBRouting Information Base RSTPRapid Spanning Tree Protocol RSVP-TE Resource Reservation Protocol - Traffic Engineering (RSVP protocol with MPLS traffic engineering extensions) SASource Address SDHSynchronous Digital Hierarchy SONETSynchronous Optical Network

88 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 88 Glossary SPTShortest Path Tree STSpanning Tree Protocol STPSpanning Tree Protocol TDMTime-Division Multiplexing TETraffic Engineering TMTraffic Management TTLTime to Live UNIUser Network Interface VCIVirtual Circuit Identifier VFIVirtual Forwarding Instance VIDVLAN Identifier VLANVirtual LAN VLANVirtual LAN VOQVirtual Output Queue VPIVirtual Path Identifier VPLSVirtual Private LAN Service VPNVirtual Private Network VPWSVirtual Private Wire Service VRVirtual Router VRFVirtual Routing and Forwarding VSIVirtual Switching Instance WFQWeighted Fair Queuing

89 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 89 Readings and References (1) MEF 4: Metro Ethernet Network Architecture Framework Part 1 Generic Framework MEF 6: Metro Ethernet Services Definition Phase 1 MEF 10.1: Metro Ethernet Services Attributes Phase 2 MEF 16: Ethernet Local Management Interface IEEE 802.1d/q WG: Media Access Control (MAC) Bridges, IEEE 1998 IEEE 802.1s, Multiple Spanning Tree, IEEE 2002 IEEE 802.1ah, Provider Backbone Bridges, Work in Progress Documents on the MEF and IEEE and WG web sites

90 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 90 Readings and References (2) L. Andersson and E. Rosen, Framework for Layer 2 Virtual Private Networks (L2VPNs), RFC 4664, September 2006 K. Kompella and Y. Rekhter, Eds., Virtual Private LAN Service: Using BGP for Autodiscovery and Signaling, RFC 4761, January 2007 V. Kompella and M. Lasserre, Eds., Virtual Private LAN Service: Using Label Distribution Protocol for Signaling, RFC 4762, January 2007 S. Bryant and P. Pate, Eds. Pseudo Wire Emulation Edge-to-Edge (PWE3) Architecture, RFC 3985, March 2005 L. Martini et al, Eds., Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP), RFC 4447, April 2006 Documents on the L2 VPN, PWE3, MPLS, and CCAMP WGs of the IETF

91 Additional Slides Metanoia, Inc. Critical Systems Thinking

92 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 92 Label Assignment and Distribution (control component) Direction from which labels flow Refers to whether LSR distributes labels on demand or voluntarily Whether LSR waits to hear from its upstream/downstream nbrs. before responding to a request for label(s) Label Retention : Liberal or Conservative Whether LSR keeps labels from a neighbor who is not currently the next hop for a FEC Labels Data Labels Data

93 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 93 A Word on Reservation Styles Always chosen by the receiver Two styles apply with RSVP-TE Fixed Filter (FF) Distinct reservation for traffic from each sender Needs unique label per sender Shared Explicit (SE) Common resvn. for traffic from the senders specified by rcvr. May assign unique label/sender Useful for p2p or mp2p LSPs

94 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 94 LDP versus BGP Signaling LDP session full mesh b/ween PEs PEs exchange labels directly New PE reconfig. mesh at all PEs FIB per VPLS per PE RRs reduce full mesh to 2 sessions/PE Cannot direct label mapping to a specific peer need label ranges New PE peering session only w/ RRs BGP-based SignalingTargeted LDP

95 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 95 L2 VPNS with BGP Autodiscovery + signaling, together via BGP with RTs (per slide 74) PE configured with its VPLS ID (if VPLS) Transmits VPLD ID or identity of attached CEs to peer PEs Includes demux value for each BGP NLRI (as a label range) Selection algorithm allows each remote PE to pick correct label for sending traffic to advertising PE BGP NLRI for L2 VPNBGP NLRI for VPLS

96 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 96 BGP-based L2 VPN (VPWS)

97 Copyright 2007 All Rights Reserved Metanoia, Inc. Critical Systems Thinking Next-Generation Systems & Networks Workshop, 17 th July. 2007, Bangalore, India 97 BGP-based L2 VPN (VPLS)


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