Practical Optical Networking

Transcription

1 1 of 22 11/15/2007 6:04 PM Practical Optical Networking Outline 1. Evolution of national R&E infrastructure 2. Physical and architectural aspects of optical nets 3. Hybrid networking 4. Testing

2 2 of 22 11/15/2007 6:04 PM Brief overview of the evolution of the US NREN Infrastructure The National Research and Education Networking community in the US played a key role in the development of the Internet The commercial Internet evolved from ARPANet and NSF-Net The Clinton-Gore administration saw a need for additional Internet technology evolution in a non-commercial environment The Internet2 project developed from that Next Generation Internet (NGI) program, in 1997 Eventually, the R&E community saw the need for a new infrastructure that leveraged advanced optical technology National Lambda Rail was started by a consortium of R&E networking groups in 2003 with the premise of owning the underlying fiber plant on a national scale Internet2 and Abilene Abilene setup as original Internet2 network service Private IP service for R&E community Routers in 12 US cities, connected via OC-48 SONET Router interfaces are OC-48 Packet over SONET (POS) Backbone SONET circuits between routers Delivered by Qwest using SONET rings SONET rings are transparent to Abilene Advantage is 50 msec recovery time for failures University users connect through "GigaPoPs" via backhaul circuits Connectivity to other non-commercial R&E networks via exchange points

3 3 of 22 11/15/2007 6:04 PM SONET resiliency example Circuit wraps to secondary (protect) path upon link loss due to fiber cut Routers never notice outage, since 50 ms is less than IGP timer values

4 4 of 22 11/15/2007 6:04 PM Regional networks Regional connectors formed as "GigaPoPs" Basically IP traffic aggregators for state or regional Higher Education campuses Support both Abilene and commodity (standard Internet service) Connections are back-hauled to "nearest" Abilene node Back-haul circuit is "free", provided by Qwest Ex: NCREN had a router at the Qwest facility in Raleigh, connected via OC-48 to Abilene router in Washington

5 5 of 22 11/15/2007 6:04 PM Upgraded Abilene to 10 Gbps backbone New routers, slightly different city mix Backbone circuits: OC-192 via DWDM (Q-wave) Abilene circuit is one wave of many on single fiber No SONET rings underlying service Fiber cut or hardware failure takes out circuit until restored Backbone needs to rely more on Layer 3 resiliency (IGP convergence) National Lambda Rail In the aftermath of the technology bubble bursting, fiber was cheap and plentiful The R&E community saw a chance to "buy" fiber and have more control over its destiny Partners: Level(3) for fiber, Cisco for technology NLR started offering services in 2003 Tiered service model: WaveNet - point-to-point 10 Gbps wave service Provided by DWDM on fiber FrameNet - point-to-point or multipoint Ethernet service Provided by Ethernet switches on a 10 GbE lambda Available in 10 GbE, GbE, or sub-gbe flavors PacketNet Traditional IP service using routers on OC-192 lambda

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7 7 of 22 11/15/2007 6:04 PM Current status Both organizations are still providing services to the community Internet2 has a new post-abilene infrastructure that provides Layer 1, 2 and 3 services, similar to NLR Additionally, provides dynamic circuit setup service NLR and Internet2 tried to merge several times over the past few years Motivation: Not enough support for two NREN providers with similar offerings Outcome: Merger talks halted in October 2007 The future is uncertain... Physical and Architectural Aspects Fiber Optic Media Technology Fiber Optic Connector Technology Campus LAN Optical Networking Technologies Network Device Optics

8 8 of 22 11/15/2007 6:04 PM Fiber Optic Media Technology Single Mode Fiber (SMF) Typically used in the Campus LAN backbone Supports long distances (multi-km) Typical Core Size: 8-10 micrometers (microns) (µm) Alternate Spelling: Single-mode Fiber Fiber Optic Media Technology (cont.) Multi-Mode Fiber (MMF) Typically used in the Campus LAN to interconnect network devices in a single building as it cannot be used for long distances (typically less than 500m). Also used in the Data Center to provide network device to network device and network device to host connectivity Typical Configuration: 62.5µm core/125µm cladding 50µm becoming popular and is already widely used in Storage Area Networks (SANs)

9 9 of 22 11/15/2007 6:04 PM Fiber Optic Connector Technology Legacy Fiber Optic Connector Technology ST - Straight Tip Keyed Quarter turn to lock in place Developed by AT&T Widely Deployed Often seen in legacy 10Base-F Deployments Fiber Optic Connector Technology (cont.) Legacy Fiber Optic Connector Technology (cont.) FC - Ferrule Connector or Fixed Connection Keyed Threaded Hard to work with (especially if you have large hands) Typically seen in SMF applications

10 10 of 22 11/15/2007 6:04 PM Fiber Optic Connector Technology (cont.) Legacy Fiber Optic Connector Technology (cont.) MTRJ (also MT-RJ) - Mechanical Transfer Registered Jack Designed by AMP Has pins for alignment MMF Only Male and Female Versions Not particularly popular Resembles UTP RJ-45 Jack Typically found in 100Base-FX deployments

11 11 of 22 11/15/2007 6:04 PM Fiber Optic Connector Technology (cont.) Legacy Fiber Optic Connector Technology (cont.) SC - Subscriber Connector Square Keyed Developed by NTT Push/Pull motion Legacy? Really? Very Popular 100Base-FX, 1000Base-X, 10GBase-SR, LR, ER, LX4 Fiber Optic Connector Technology (cont.) Current Fiber Optic Connector Technology LC - Lucent Connector (SFP, XFP) Offers excellent performance Easy to use Has become the connector of choice for network equipment vendors

12 12 of 22 11/15/2007 6:04 PM Campus LAN Optical Networking Technologies Legacy Campus LAN Optical Networking Technologies ATM Asynchronous Transfer Mode Typically used as backbone transport Typical Speeds: STS-3/OC Mbps STS-12/OC Mpbs STS Synchronous Transport Signal Electrical equivalent of SONET OC-level Campus LAN Optical Networking Technologies (cont.) Legacy Campus LAN Optical Networking Technologies (cont.) FDDI - Fiber Data Distributed Interface Typically used as backbone transport ANSI Standard X3T12 Dual Counter-Rotating Rings 100Mbps FDDI Rings may be up to 200km

13 13 of 22 11/15/2007 6:04 PM Campus LAN Optical Networking Technologies (cont.) Legacy Campus LAN Optical Networking Technologies (cont.) 10Base-FL - 10Mbps over Fiber Link (10Base-FL is covered under 10Base-F which is the standard for Fiber Optic Active and Passive Star-based Ethernet segments) Covers distances up to 2km Compatible with FOIRL (Fiber Optic Inter Repeater Link). FOIRL works in distances up to 1km, repeater dependent

14 14 of 22 11/15/2007 6:04 PM Campus LAN Optical Networking Technologies (cont.) Legacy Campus LAN Optical Networking Technologies (cont.) 100Base-FX - 100Mbps Ethernet over Fiber Defined in 802.3u Half and Full-Duplex (412m and 2km respectively) Campus LAN Optical Networking Technologies (cont.) Current Campus LAN Optical Networking Technologies 1Gbps Ethernet Base-X, 802.3z Widely Deployed Can be deployed over SMF or MMF Used as backbone and building transport Often aggregated on the backbone Has reached commodity status as a backbone technology Also used in data centers to attach hosts to the network

15 15 of 22 11/15/2007 6:04 PM Campus LAN Optical Networking Technologies (cont.) Current Campus LAN Optical Networking Technologies (cont.) 10Gbps Ethernet - 10GBase-SR, LR, ER, LX4, etc., 802.3ae Becoming much more common in the Campus Backbone and Data Centers Still relatively expensive (although many vendors disagree) Vendors working to provide greater density at a lower cost Network Device Optics 1Gbps GBICS - Gigabit Interface Converters SFPs - Small Form Factor Pluggable Gigabit Interface Converters Both form factors offer models that operate over SMF and MMF to distances as great as 70km In addition, there are some Coarse and Dense Wave Division Multiplexing models are available

16 16 of 22 11/15/2007 6:04 PM Network Device Optics (cont.) 10Gbps XENPAK X2 XFP All three form factors offer models that operate over SMF and MMF to distances as great as 40km. In addition, there are some Coarse and Dense Wave Division Multiplexing models are available. Power Budgets To pick the correct optic you need to know the power budget of the optic and the loss present on the physical medium: Power Budget = (Launch Power) - (Receive Sensitivity) Power budget - (Loss from splices + Loss from connectors + safety margin) = Total Power Budget

17 17 of 22 11/15/2007 6:04 PM Power Budgets (cont.) Sample Calculation: Power Budget = (Launch Power) - (Receive Sensitivity) Power Budget = -9.5 dbm - (-17 dbm) Power Budget = 7.5 dbm Power Budgets (cont.) Sample Average Fiber Loss Values: 850nm MMF 62.5/125 µm Attenuation/km = 3.0 db Attenuation/connector =.75 db Attenuation/splice = 0.1 db Safety Margin = 3.0 db

18 18 of 22 11/15/2007 6:04 PM Power Budgets (cont.) Sample Calculation Fiber Loss: Loss = Attenuation/km * km + Attenuation/Splice * Number of Splices + Attenuation/Connector * Number of Connectors + Margin of Safety = Total Loss Loss = (0.30 * 20) + (0.1 * 2) + (.75 * 2) = 10.7 db Power Budgets (cont.) Bottom Line: If your loss exceeds your power budget you won't be able to light that link!!!

19 19 of 22 11/15/2007 6:04 PM Hybrid Networking Basic Concept: Separate 'data plane' from 'control plane' The Premise: Optical networks are much faster if the data stays in the optical domain and isn't converted back and forth between optical and electrical domain. Hybrid Networking What is data plane? All hardware, software, and cabling used to carry information (data) from one place to another. What is the control plane? All equipment used to determine and implement the configuration of the data plane.

20 20 of 22 11/15/2007 6:04 PM Hybrid Networking How it's done: Optical switch network for data plane GMPLS protocol (and associated hardware) for control plane Hybrid Networking GMPLS - Generalized Multi-Protocol Label Switching Extension of MPLS Separates control and data plane (surprise) RFC 3945

21 21 of 22 11/15/2007 6:04 PM Hybrid Networking DRAGON Project: Dynamic Resource Allocation via GMPLS Optical Networks Hybrid Networking Cheetah Project: Circuit-switched High-speed End-to-End Transport ArcHitecture

22 22 of 22 11/15/2007 6:04 PM Hybrid Networking Testing Physical Network Node to Node End to End