1 / 98

GMPLS networks and optical network testbeds

GMPLS networks and optical network testbeds. Malathi Veeraraghavan Professor Charles L. Brown Dept. of Electrical & Computer Engineering University of Virginia mvee@virginia.edu Tutorial at ICACT09 Feb. 2009. GMPLS: Generalized MultiProtocol Label Switched networks

derica
Télécharger la présentation

GMPLS networks and optical network testbeds

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. GMPLS networks and optical network testbeds Malathi Veeraraghavan Professor Charles L. Brown Dept. of Electrical & Computer Engineering University of Virginia mvee@virginia.edu Tutorial at ICACT09 Feb. 2009 GMPLS: Generalized MultiProtocol Label Switched networks (MPLS, SONET, WDM, SDM, VLAN)

  2. Outline • Principles • Different types of connection-oriented networks • Technologies • Single network • Internetworking • Usage • Commercial networks • Research & Education Networks (REN)

  3. Principles • Types of switches and networks • Bandwidth sharing modes • TCP in connectionless (IP) networks • Immediate-request and book-ahead modes in connection-oriented networks

  4. Types of switches

  5. Types of networks Connection-oriented

  6. How is bandwidth shared on a connectionless packet-switched network? • Pre-1988 IP network: • Just send data without reservations or any mechanism to adjust rates  congestion collapses! • Van Jacobson's 1988 contribution: • Added congestion control to TCP • Sending TCP adjusts rate • Advantages: • Proportional fairness • High utilization • Disadvantages: • No rate guarantees • No temporal fairness (job seniority)

  7. TCP throughput • B: Throughput in congestion-avoidance phase • RTT: Round-trip time • b: an ACK is sent every b segments (b is typically 2) • p: packet loss rate on path • T0: initial retransmission time out in a sequence of retries • Effective rate = min (r,B) • r: bottleneck link rate • Padhye, Firoui, Towsley, Kurose, ACM Sigcomm 98 paper

  8. TCP throughput Case Input parameters Mean transfer delay for a 1GB file (s) Packet loss rate Bottleneck link rate Round-trip delay Case 1 0.0001 100 Mb/s 0.1ms 82.25 Case 2 5ms 89.45 ~21Mbps Case 3 50ms 396.5 Case 4 1Gbps 0.1ms 8.25 Case 5 5ms 39.6 Case 6 50ms 395.7 Case 7 0.001 100 Mbps 0.1ms 82.93 Case 8 5ms 135.4 Case 9 50ms 1293 Case 10 1Gbps 0.1ms 8.64 Case 11 5ms 129.4 Case 12 50ms 1287 Case 13 0.01 100 Mbps 0.1ms 92.41 Case 14 5ms 471.7 ~2Mbps Case 15 50ms 4417 Case 16 1Gbps 0.1ms 12.43 Case 17 5ms 441.7 Case 18 50ms 4387

  9. Bandwidth sharing in circuit networks(immediate-request mode) • Key difference: • Admission control • Intrinsic to circuit networks: position based mux • Send a call setup request: • if requested bandwidth is available, it is allocated to the call • if not, the call is blocked (rejected) • M/G/m/m model: • m: number of circuits

  10. r m ua 4 17 117 24.8% 58.2% 84.6% 1 10 100 ErlangB formula r: offered traffic load in Erlangs : call arrival rate 1/:mean call holding time m: number of circuits Pb: call blocking probability ub: utilization For a 1% call blocking probability, i.e., Pb = 0.01 If m is small, high utilization can only be achieved along with high call blocking probability

  11. Bandwidth sharing mechanismsin CO networks Needed if per-call circuit rate is a large fraction of link capacity (e.g., 1Gbps circuits on a 10Gbps link, m = 10) Bandwidth sharing mechanisms Book-ahead Immediate-request call duration specified unspecified call duration BA-n/BA-First VBDS (Varying-Bandwidth Delayed Start) session-type requests data-type requests BA-n BA-First Users specify a set of call-initiation time options Users are given first available timeslot X. Zhu, Ph.D. Thesis, UVA, http://www.ece.virginia.edu/mv/html-files/students.html

  12. Comparison of Immediate-Request (IR) and Book-Ahead (BA) schemes • Example • To achieve a 90% utilizationwith a call blocking probability less than 10% • BA-First schemes are needed when m < 59 • To achieve a 90% utilization with a call blocking probabilityless than 20% • BA-First schemes are needed when m < 32 U: utilization K: number of time periods in advance-reservation window m=10, K=10, U = 80%: PB = 0.4% BA m=10, U = 80%: PB = 23.6% m=100, U = 80%: PB= 0.4% IR

  13. Virtual circuit (VC) networks Call Admission Control Bandwidth sharing more complex, but better utilization PLUS service guarantees Needed in circuit networks Scheduling (example: weighted fair queueing) Traffic shaping/policing (example: leaky-bucket algorithm) Two additional dimensions in VC networks

  14. Outline • Principles • Different types of connection-oriented networks • Technologies • Single network • Internetworking • Usage • Commercial networks • Research & Education Networks (REN)

  15. Technologies • GMPLS networks • Data-(user-) plane protocols • packet-switched: MPLS, VLAN Ethernet • circuit-switched: SONET/SDH, WDM, SDM (space div. mux) • Control-plane protocols: • RSVP-TE: signaling protocol • OSPF-TE: routing protocol • LMP: link management protocol • Internetworking • GFP, VCAT, LCAS for SONET/SDH • PWE3 for MPLS networks • Digital wrapper for OTN

  16. Label Value CoS S TTL 20 Bits 3 1 8 Multiprotocol label switching (MPLS) • MPLS Header: • Label Value: Label used to identify the virtual circuit • Class of Service (CoS): Experimental field, Used for QoS support • S: Identifies the bottom of the label stack • TTL: Time-To-Live value • Virtual circuits: Label Switched Path (LSP) MPLS Header

  17. IEEE 802.1Q Ethernet VLAN new fields Type/Len Dest. MAC Address Source MAC Address TPID TCI Data FCS FCS: Frame Check Sequence VLAN Tag User Priority 802.1Q Tag Type CFI VLAN ID 2 Bytes 3 Bits 1 Bit 12 Bits

  18. VLAN Tag Fields • Tag Protocol Identifier (TPID) • 802.1Q Tag Protocol Type – set to 0x8100 to identify the frame as a tagged frame • Tag Control Information (TCI) • User Priority • As defined in 802.1p, 3 bits represent eight priority levels • CFI • Canonical Format Indicator, set to indicate the presence of an Embedded-RIF • VLAN ID • Uniquely identifies the frame's VLAN

  19. SONET/SDH rates(number is the multiplier) Example: STS-48 frame has 48 x 90 columns in 125 s STS-1: 90 columns by 9 rows in 125s Tanenbaum

  20. Optical transport networks (OTN) • G. 872 layers • OTS: Optical Transmission Section • OMS: Optical Multiplex Section • OCh: Optical Channel • G.709: • Technique for mapping client signals onto the Optical Channel via layers: • OTU: Optical Channel Transport Unit, and • ODU: Optical Channel Data Unit

  21. Layers within an OTN Courtesy: T. Walker's tutorial

  22. OTN Hierarchy • Electrical domain: • OTU: Optical Channel Transport Unit • ODU: Optical Channel Data Unit • OPU: Optical Channel Payload Unit Low layer Higher layers Courtesy: T. Walker's tutorial

  23. G. 709 Optical Channel frame structure (digital wrapper) • Optical channel (OCh) overhead: support operations, administration, and maintenance functions • OCh payload: can be STM-N, ATM, IP, Ethernet, GFP frames, OTN ODUk, etc. • FEC: Reed-Solomon RS(255, 239) code recommended; roughly introduces a 6.7% overhead • Frame size: 4 rows of 4080 bytes • Frame period: • OTU1 – 48.971 μs (payload data rate: roughly 2.488 Gbps ) • OTU2 – 12.191 μs (payload data rate: roughly 9.995 Gbps ) • OTU3 – 3.035 μs (payload data rate: roughly 40.15 Gbps ) OCh overhead OCh payload FEC

  24. Technologies • GMPLS networks • Data-(user-) plane protocols • packet-switched: MPLS, VLAN Ethernet, Intserv IP • circuit-switched: SONET/SDH, WDM, SDM • Control-plane protocols: • RSVP-TE: signaling protocol • OSPF-TE: routing protocol • LMP: link management protocol • Internetworking • GFP, VCAT, LCAS for SONET/SDH • PWE3 for MPLS networks • Digital wrapper for OTN

  25. The evolution ofResource reSerVation Protocol (RSVP) • RSVP (RFC2205, 1997) • RSVP-TE (RFC 3209, 2001) • RSVP-TE GMPLS Extension (RFC 3471, 3473, 2003) • RSVP-TE GMPLS Extension for SONET/SDH (RFC 3946, 2004, RFC 4606, 2006)

  26. Purpose of signaling(needed only in CO networks) • Functions: • Call setup: • Route selection • Admission control: sufficient bandwidth? • Switch fabric configuration of each switch • recall position based multiplexing • Call release • release bandwidth for use by others

  27. Dest. Next hop III-B III-B III-C III-C Dest. Next hop III-* III Circuit-switched networksPhase 1:Routing protocol exchanges + routing table precomputation • Routing protocols exchange: • topology • address reachability • loading conditions II Host I-A Host III-B I III IV Host III-C Dest. Next hop V III-* IV

  28. a b d c Circuit-switched networksPhase 2: Signaling for call setup Connection setup actions at each switch on the path: • Parse message to extract parameter values • Lookup routing table for next hop to reach destination • Read and update CAC (Connection Admission Control) table • Select timeslots on output port • Configure switch fabric: write entry into timeslot mapping table • Construct setup message to send to next hop Connection setup (Dest: III-B; BW: OC1; Timeslot: a, 1) II b Host I-A a III I Host III-B c b c V IV a d Dest. Next hop Routing table III-* IV

  29. a b d c Circuit-switched networksPhase 2: Signaling for call setup Connection setup actions at each switch on the path: • Parse message to extract parameter values • Lookup routing table for next hop to reach destination • Read and update CAC (Connection Admission Control) table • Select timeslots on output port • Configure switch fabric: write entry into timeslot mapping table • Construct setup message to send to next hop Connection setup (Dest: III-B; BW: OC1; Timeslot: a, 1) II b Host I-A a III I Connection setup Host III-B c b c V IV a d Dest. Next hop Routing table III-* IV Interface (Port); Capacity; Avail timeslots CAC table Next hop c; OC12; 1, 4, 5 IV INPUT Port /Timeslot OUTPUT Port/Timeslot Timeslot mapping table a/1 c/1 Update to remove timeslot 1 from available list

  30. a b d c Circuit-switched networksPhase 2: Signaling for call setup II b Host I-A a Connection setup III I Host III-B c b c V IV a Connection setup (Dest: III-B; BW: OC1; Timeslot: a, 1) d INPUT Port /Timeslot OUTPUT Port/Timeslot Time slot could be different on each hop a/1 c/2 Perform same set of 6 connection setup steps at switch IV write timeslot mapping table entry, update CAC table and send connection setup message to the next hop

  31. a b d c Circuit-switched networksPhase 2: Signaling for call setup INPUT Port /Timeslot OUTPUT Port/Timeslot II d/2 b/1 b Host I-A a Connection setup III I Host III-B c b c V IV a Connection setup d Circuit setup complete Perform same set of 6 connection setup steps at switch III Reverse setup-confirmation messages typically sent from destination through switches to source host

  32. Circuit-switched networksPhase 3: User-data flow • Bits arriving at switch I on time slot 1 at port a are switched to time slot 1 of port c IN Port /Timeslot OUT Port/Timeslot 1 2 II d/2 b/1 b 1 2 1 2 a Host I-A a III I Host III-B b c b d c c 1 2 IV a d V IN Port /Timeslot OUT Port/Timeslot IN Port /Timeslot OUT Port/Timeslot a/1 c/1 a/1 c/2

  33. Release procedure • When a communication session ends, there is a hop-by-hop release procedure (similar to the setup procedure) to release timeslots/wavelengths for use by new calls

  34. RSVP messages and parameters • Messages: • Setup: Path (forward) and Resv (reverse) • Release: PathTear, ResvTear • Parameters • Destination: SESSION object • Bandwidth: Sender Tspec object or SONET/SDH Tspec • Timeslot/Wavelength: • Generalized LABEL for ports, wavelengths • SUKLM label for SONET/SDH • Only supports immediate-request circuits/virtual circuits • No time-dimension parameters for book-ahead

  35. Explicit Route Object (ERO) • A list of groups of nodes along the explicit route (generically called "source route") • Thinking: source routing is better for calls than hop-by-hop routing as it can take into account loading conditions • Constrained shortest path first (CSPF) algorithm executed at the first node to compute end-to-end route, which is included in the ERO

  36. Control-plane message transport: inband or out-of-band • Separation of control plane from data plane in GMPLS networks - out-of-band Internet IP router IP router Control-plane messages Ethernet control ports GMPLS Network Ethernet control ports Circuit established SONET or WDM switch SONET or WDM switch Data-plane link

  37. Interface ID field • Control plane separation: • Requires upstream switch to identify on which data-plane interface the virtual circuit should be routed • Interface ID field defined in the tag-length-value format • Embedded within the RSVP-HOP object • Carried in PATH messages

  38. Technologies • GMPLS networks • Data-(user-) plane protocols • packet-switched: MPLS, VLAN Ethernet, Intserv IP • circuit-switched: SONET/SDH, WDM, SDM • Control-plane protocols: • RSVP-TE: signaling protocol • OSPF-TE: routing protocol • LMP: link management protocol • Internetworking • GFP, VCAT, LCAS for SONET/SDH • PWE3 for MPLS networks • Digital wrapper for OTN

  39. OSPF-TE: Open Shortest Path First -Traffic Engineering • To advertise loading conditions • New parameters: • Maximum bandwidth of a link • Maximum reservable bandwidth: can be greater than the maximum bandwidth to support oversubscription • Unreserved bandwidth • RFC 3630 - for MPLS networks • Only supports immediate-request circuits/virtual circuits • No time-dimension parameters for book-ahead

  40. OSPF-TE extensions for GMPLS • RFC 4202 and 4203 • Main new parameters • Shared Risk Link Group • Interface Switching Capability Descriptor (ISCD) • Allows multiple types of switching techniques • Example for SONET: Minimum LSP Bandwidth: OC1 on a SONET interface if the switch demultiplexes down to OC1 level

  41. Difference between labels in MPLS and circuit-switched GMPLS • In circuit-switched GMPLS networks, labels are not carried in the data plane • Labels in circuit-switched networks identify "position" of data for the circuit - time or wavelength • In circuit-switched GMPLS networks, cannot assign labels without associated bandwidth reservation • In usage section, we will see the value of this feature in MPLS networks • See two applications: traffic engineering, VPLS (addressing benefits)

  42. Technologies • GMPLS networks • Data-(user-) plane protocols • packet-switched: MPLS, VLAN Ethernet, Intserv IP • circuit-switched: SONET/SDH, WDM, SDM • Control-plane protocols: • RSVP-TE: signaling protocol • OSPF-TE: routing protocol • LMP: link management protocol • Internetworking • GFP, VCAT, LCAS for SONET/SDH • PWE3 for MPLS networks • Digital wrapper for OTN

  43. LMP procedures • Control channel management • Set up and maintain control channels between adjacent nodes • Link property correlation • Aggregate multiple data links into a TE link • Synchronize TE link properties at both ends • Link connectivity verification (optional) • Data plane discovery; If_Id exchange; physical connectivity verification • Fault management (optional) • Fault notification and localization Reference: IETF RFC 4204

  44. Control-plane security • Need authentication and integrity for all control-plane exchanges • Since RSVP, OSPF, LMP run over IP, IPsec is a possible solution

  45. Technologies • GMPLS networks • Data-(user-) plane protocols • packet-switched: MPLS, VLAN Ethernet, Intserv IP • circuit-switched: SONET/SDH, WDM, SDM • Control-plane protocols: • RSVP-TE • OSPF-TE • LMP • Internetworking • GFP, VCAT, LCAS for SONET/SDH • PWE3 for MPLS networks • Digital wrapper for OTN

  46. Why internetworking? • GMPLS networks do not exist as standalone entities • Instead they are part of the Internet: • Obvious usage: to interconnect IP routers • Newer uses: • Commercial: interconnect Ethernet switches in geographically distributed LANs via point-to-point links or VPNs • Research & Education networks: connect GbE and 10GbE cards on cluster computers and storage devices to GMPLS networks

  47. Obvious usage • Router-to-router circuits and virtual circuits Internet IP router IP router GMPLS Network SONET or WDM switch SONET or WDM switch

  48. Router-to-router usage • OSPF-enabled usage • simply treat MPLS virtual circuit or GMPLS circuit as a link between routers • allow routing protocol to include these in routing table computations • Data-plane • IP over MPLS • IP over PPP over SONET • Packet-over-SONET (PoS)

  49. Newer uses • New type of gateway functionality • No IP layer involvement • Instead Ethernet frames are mapped onto MPLS virtual circuits or GMPLS circuits • port mapped • VLAN mapped • Cisco and Juniper routers support Ethernet over MPLS • Sycamore and Ciena SONET switches support Ethernet over GMPLS

  50. Ethernet port mapped over MPLS • Send all Ethernet frames received on ports I and II on to the MPLS LSP • MPLS LSP: Pseudo-wire • Enterprise can allocate IP addresses from one subnet: Virtual Private LAN Service (VPLS) • Explains one use for MPLS virtual circuits with no bandwith allocation SDM-to-MPLS gateway SDM-to-MPLS gateway Internet IP router/MPLS switch IP router/MPLS switch Pseudowire II I MPLS LSP (virtual circuit) Ethernet switch Ethernet switch Mux scheme on pseudowire: Ethernet Enterprise 2 Enterprise 1 Gateway: interfaces have different MUX schemes unlike switch, which has same MUX scheme on all links SDM: Space Division Multiplexing

More Related