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					    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)
                                                              1
                 Outline
• Principles
  – Different types of connection-oriented
    networks
• Technologies
  – Single network
  – Internetworking
• Usage
  – Commercial networks
  – Research & Education Networks (REN)
                                             2
              Principles
• Types of switches and networks
• Bandwidth sharing modes
  – TCP in connectionless (IP) networks
  – Immediate-request and book-ahead
    modes in connection-oriented networks




                                            3
              Types of switches
     Multiplexing technique on   Circuit      Packet switch (PS)
             data-plane links    switch (CS) - header based
Admission                        - position
                                 based
control in                       (port, time,
control plane?                   lambda)
Connectionless (CL)              Not an      e.g., Ethernet
- no admission control           option
Connection-oriented (CO)         e.g.,       Virtual-circuit
- admission control              telephone   e.g., MPLS, ATM
                                 SONET
                                 WDM

                                                               4
                  Types of networks

  Support function Addressing           Routing   Signaling
                   (in data or
Network            control
type               plane?)

Connectionless (CL) Data plane                   

Circuit Switched       Control plane             
(CS)
Virtual circuit        Control plane             
(VC)


                  Connection-oriented
                                                              5
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)

                                                           6
                 TCP throughput
                                  1
        B
                 2bp              3bp
             RTT      T0 min(1,3     ) p(1  32 p 2 )
                  3                8

•   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
                                                                   7
                    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
Case 3                                                      50ms             396.5           ~21Mbps
Case 4                             1Gbps                    0.1ms             8.25
Case 5                                                       5ms              39.6
Case 6                                                      50ms             395.7
Case 7    0.001                     100                     0.1ms            82.93
                                    Mbps
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                     0.1ms            92.41
                                    Mbps
Case 14                                                      5ms             471.7
Case 15                                                     50ms              4417           ~2Mbps
Case 16                            1Gbps                    0.1ms            12.43
Case 17                                                      5ms             441.7
                                                                                              8
Case 18                                                     50ms              4387
 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

                                                   9
                ErlangB formula
                 m / m!            : offered traffic load in Erlangs
       Pb                          : call arrival rate
                m k
                / k!             1/: mean call holding time
             k 0                 m: number of circuits
                                   Pb: call blocking probability
            (1  Pb )  
       ub                          ub: utilization
                  m

       For a 1% call blocking probability, i.e., Pb = 0.01
                      m      ua
                                          If m is small, high
                      4     24.8%         utilization can only be
           1
                                          achieved along with high
           10         17    58.2%
                                          call blocking probability
           100        117   84.6%
                                                                         10
               Bandwidth sharing mechanisms
                      in CO networks
 Needed if per-call
 circuit rate is a large            Bandwidth sharing mechanisms
 fraction of link capacity
 (e.g., 1Gbps circuits on a
 10Gbps link, m = 10)       Book-ahead                      Immediate-request
                     call duration specified                      unspecified call duration



            BA-n/BA-First                                   VBDS
     session-type requests                     (Varying-Bandwidth Delayed Start)
                                                      data-type requests
       BA-n                BA-First
Users specify a set of    Users are given first
call-initiation time      available timeslot
options

           X. Zhu, Ph.D. Thesis, UVA, http://www.ece.virginia.edu/mv/html-files/students.html
                                                                                             11
     Comparison of Immediate-Request (IR)
        and Book-Ahead (BA) schemes
• Example
  – To achieve a 90% utilization
    with a call blocking probability
    less than 10%
    • BA-First schemes are needed
      when m < 59

  – To achieve a 90% utilization
    with a call blocking probability
    less than 20%
    • BA-First schemes are needed
      when m < 32


U: utilization
K: number of time periods in
   advance-reservation window
       IR m=10, U = 80%: PB = 23.6%     BA m=10, K=10, U = 80%: PB = 0.4%
            m=100, U = 80%: PB = 0.4%                                 12
       Virtual circuit (VC) networks
                         Call Admission Control
 Bandwidth sharing
 more complex, but                         Needed in circuit
 better utilization                           networks
 PLUS service
 guarantees




                              Scheduling
                              (example: weighted fair queueing)

Traffic shaping/policing
(example: leaky-bucket algorithm)            Two additional
                                               dimensions      13

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

                                                           15
Multiprotocol label switching
          (MPLS)
         MPLS Header


          Label Value              CoS S         TTL
              20 Bits               3   1          8

• 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)
    IEEE 802.1Q Ethernet VLAN
                      new fields
Dest. MAC Source MAC
                     TPID TCI Type              Data           FCS
Address   Address             /Len
                                                            FCS: Frame
                                                            Check
                                                            Sequence



                       VLAN Tag
                            User
       802.1Q Tag Type              CFI         VLAN ID
                           Priority
            2 Bytes            3 Bits   1 Bit     12 Bits
              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
   SONET/SDH rates
(number is the multiplier)




Example: STS-48 frame has 48 x 90 columns in 125 s   19
      STS-1: 90 columns by 9 rows in 125 s            Tanenbaum
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
                                                 20
Layers within an OTN




                                      21

     Courtesy: T. Walker's tutorial
                 OTN Hierarchy
  Low layer




Higher layers




      • Electrical domain:
           – OTU: Optical Channel Transport Unit
           – ODU: Optical Channel Data Unit
           – OPU: Optical Channel Payload Unit         22

                      Courtesy: T. Walker's tutorial
    G. 709 Optical Channel frame structure
               (digital wrapper)

       OCh overhead        OCh payload          FEC

• 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 )23
                 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

                                                          24
          The evolution of
Resource 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)

                                   25
     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


                                                   26
                Circuit-switched networks
           Phase 1: Routing protocol exchanges
             + routing table precomputation

                                                   Dest.   Next hop
                                     II            III-B       III-B
                                                   III-C       III-C
Host                                                                   Host
I-A              I
                                                 III                   III-B

                                 IV                                    Host
 Dest.    Next hop                                                     III-C
                                                           V
 III-*      IV
                             Dest.    Next hop
                             III-*        III


         • Routing protocols exchange:
            – topology
            – address reachability
            – loading conditions                                       27
                     Circuit-switched networks
                   Phase 2: Signaling for call setup
          Connection setup
          (Dest: III-B;
          BW: OC1;                               II
          Timeslot: a, 1)
                             b                                         a
      Host          a
                        I                                                  III
      I-A                        c                                                   b           Host
                                                 b
                                                                            d    c               III-B
                                                       c
                                        a        IV                                      V
           Dest.    Next hop                               d
Routing
table      III-*        IV

                                     Connection setup actions at each switch on the path:
                                            1.        Parse message to extract parameter values
                                            2.        Lookup routing table for next hop to reach destination
                                            3.        Read and update CAC (Connection Admission Control)
                                                      table
                                            4.        Select timeslots on output port
                                            5.        Configure switch fabric: write entry into timeslot
                                                      mapping table
                                            6.        Construct setup message to send to next hop
                                                                                                     28
                          Circuit-switched networks
                        Phase 2: Signaling for call setup
           Connection setup
           (Dest: III-B;
           BW: OC1;                                               II
           Timeslot: a, 1)
                                      b                                                   a
         Host              a
                                  I                Connection                                 III
         I-A                              c                                                              b               Host
                                                   setup     b
                                                                                               d     c                   III-B
                                                                        c
                                                              a   IV                                         V
                Dest.       Next hop                                        d
 Routing
 table          III-*          IV
                                                                       Connection setup actions at each switch on the path:
                       Interface (Port);
                                                                           1. Parse message to extract parameter values
 CAC       Next hop Capacity; Avail timeslots
                                                                           2. Lookup routing table for next hop to reach destination
 table                                                                     3. Read and update CAC (Connection Admission Control)
                 IV            c; OC12; 1, 4, 5                               table
                                                                           4. Select timeslots on output port
                         INPUT                 OUTPUT                      5. Configure switch fabric: write entry into timeslot
Timeslot                                                                      mapping table
                      Port /Timeslot          Port/Timeslot
mapping table                                                              6. Construct setup message to send to next hop
                            a/1                   c/1
                                                                                Update to remove timeslot 1                 29
                                                                                from available list
                Circuit-switched networks
              Phase 2: Signaling for call setup

                                       II

                         b                                  a
       Host      a                           Connection
                     I                                            III
       I-A                   c               setup                          b       Host
                                      b
                                                                   d    c           III-B
                                             c
                                  a   IV                                        V
              Connection setup                   d
                 (Dest: III-B;
                  BW: OC1;            INPUT        OUTPUT
                Timeslot: a, 1)    Port /Timeslot Port/Timeslot
Time slot
                                           a/1        c/2
could be different
on each hop
              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                           30
          Circuit-switched networks
        Phase 2: Signaling for call setup
                                                                INPUT        OUTPUT
                                                             Port /Timeslot Port/Timeslot
                                  II
                                                                        d/2            b/1
                   b                                a
Host       a                           Connection
               I                                        III
I-A                    c               setup                        b                    Host
                                 b
                                                         d      c                        III-B
                                       c
                             a   IV                                      V        Connection
                                           d
                                                                                  setup
                                                                              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                               31
                    Circuit-switched networks
                     Phase 3: User-data flow

                                                                                   IN           OUT
            1       2                                                        Port /Timeslot Port/Timeslot
                                                  II
                                                                                      d/2              b/1
                              b   1    2                   1         2   a
   Host         a
                         I                                                    III
   I-A                        c                                                            b                 Host
                                                  b
                                                       c                      d        c                     III-B
                                                                                               1   2
                                        a     IV           d
      IN           OUT                                                            V
Port /Timeslot Port/Timeslot
                                            IN           OUT
      a/1               c/1           Port /Timeslot Port/Timeslot
                                            a/1                c/2


    • Bits arriving at switch I on time slot 1 at port a
      are switched to time slot 1 of port c
                                                                                                             32
        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



                                     33
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
                                                         34
  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


                                             35
 Control-plane message transport:
      inband or out-of-band
• Separation of control plane from data
  plane in GMPLS networks - out-of-band
                IP router       Internet        IP router


                                                    Control-plane messages

Ethernet control ports                          Ethernet control ports
                            GMPLS Network
                                                                Circuit
                                                              established
                   SONET                         SONET
                or WDM switch                 or WDM switch


                            Data-plane link                              36
            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




                                                           37
                 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

                                                          38
 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
                                                  39
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

                                                 40
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)


                                                                  41
                 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

                                                          42
            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

                                                   43
                 Reference: IETF RFC 4204
      Control-plane security
• Need authentication and integrity for
  all control-plane exchanges
• Since RSVP, OSPF, LMP run over IP,
  IPsec is a possible solution




                                      44
                 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

                                                          45
       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

                                                            46
               Obvious usage
• Router-to-router circuits and virtual
  circuits
          IP router       Internet       IP router




                      GMPLS Network



             SONET                       SONET
          or WDM switch               or WDM switch



                                                      47
     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)
                                             48
               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
                                              49
                   Ethernet port mapped
                        over MPLS
     SDM-to-MPLS gateway                                     SDM-to-MPLS gateway
         IP router/MPLS switch             Internet        IP router/MPLS switch
                                        Pseudowire
                         I                                  II

                                 MPLS LSP (virtual circuit)
 Ethernet switch                                                    Ethernet switch
                             Mux scheme on pseudowire: Ethernet

Enterprise 1       Gateway: interfaces have different MUX schemes        Enterprise 2
                   unlike switch, which has same MUX scheme on all links
      •   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
                                                                                        50
                                     SDM: Space Division Multiplexing
               Ethernet VLAN mapped
                     over MPLS
                                              VLAN-to-MPLS gateway
     VLAN-to-MPLS gateway
         IP router/MPLS switch   Internet   IP router/MPLS switch

                    I                        II

                                 MPLS LSP
 Ethernet switch                                    Ethernet switch

Enterprise 1                                             Enterprise 2



 • Extract frames carrying a specific VLAN ID tag on Ethernet
   ports I and II and map only these frames on to the MPLS LSP

                                                                        51
     Ethernet port or VLAN mapped
          over GMPLS circuits
SDM-to-SONET/WDM gateway                      SDM-to-SONET/WDM gateway
   SONET or WDM switch                              SONET or WDM switch


                    I                          II

                            SONET/SDH/WDM
  Ethernet switch               circuit                Ethernet switch

 Enterprise 1                                               Enterprise 2



       •   Send all frames or frames matching a given VLAN ID tag from
           Ethernet ports I and II on to the SONET/SDH/WDM circuit
       •   SONET/SDH/WDM switches now have Fast Ethernet/GbE/10GbE
           interfaces in addition to SONET/SDM or WDM interfaces
                                                                           52
        Commercial services
• EPL: Ethernet private line: map an
  Ethernet port to a SONET/SDH circuit
• Fractional-EPL: Map a GbE port to a lower-
  rate SONET circuit
  – Pause frames sent from switch to client node if
    buffer fills up
• V-EPL: Lower-rate VLAN mapped to an
  equivalent-rate SONET circuit
• MetroEthernet Forum: E-Line and E-LAN

                                                             53
          page 110 of GFP section reference: SONET focused
             Technology
• So what technologies are required for
  this type of internetworking:
  – mapping Ethernet frames on to
    MPLS/GMPLS virtual circuit/circuit
    mapping?




                                         54
                 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

                                                          55
      Why do we need Generic
     Framing Procedure (GFP)?
• The framing techniques used in other data-link layer
  protocols have problems
• For example, IP packets are carried over SONET using
  PPP/HDLC frames (called PoS)
   – HDLC inserts idle frames because SONET is synchronous it
     needs a constant flow of frames to avoid losing synchronization
• But, there is a problem:
   – HDLC uses flags for frame delineation. The issue with this
     framing technique is that if the flag pattern occurs in the
     payload, an escape byte has to be inserted
   – This causes an increase in the required bandwidth
   – The amount of increase is payload-dependent



                                                                   56
                             page 98 of reference
      Other framing techniques
• HEC - Header Error Control
   – this is the CRC framing technique used in ATM
   – "A header CRC hunting mechanism is employed by the receiver
     to extract the ATM cells from the bit/byte synchronous
     stream. The HEC location is fixed and ATM cell length is fixed.
     Starting from the assumed cell boundary, the ATM receiver
     compares its computed HEC value for the assumed ATM cell
     header against the HEC value indicated by the assumed HEC
     field. Cell stream delineation is declared after positive
     validations of the incoming HEC fields of a few consecutive
     ATM cells."
• ATM cells are fixed in length, but Ethernet frames are
  variable-length
• Therefore, we need a length field in order to implement this
  HEC-based frame delineation mechanism
                                                                   57
                            pages 96-97 of reference
          Main features of the
             GFP protocol
• Common aspects (applicable to all client signals):
   – HEC + Length based delineation
      • Core header has payload length and HEC
   – Error control: error detection
      • Payload type HEC, payload Frame Check Sequence (CRC-32)
   – Multiplexing: linear and ring extension headers
   – Idle frames are sent to maintain synchronization as in
     HDLC
   – Scrambling as in ATM:
      • core header + payload scrambling
   – Client management - client fail signal
• Client-dependent aspects:
   – Client-specific encapsulation techniques
                                                              58
                          page 68 of reference
        Virtual Concatenation (VCAT)
           for increased efficiency
                   SONET/SDH payload mapping            SONET/SDH with VCAT
  Data signal                                        payload mapping and bandwidth
                     and bandwidth efficiency                  efficiency


    Ethernet
                       STS-1/VC-3 – 21%                VT1.5-7v/VC-11-7v – 89%
   (10 Mb/s)


 Fast Ethernet
                       STS-3c/VC-4 – 67%              VT1.5-64v/VC-11-64v – 98%
  (100 Mb/s)


Gigabit Ethernet                                      STS-3c-7v/VC-4-7v –95%
                     STS-48c/VC-4-16c – 42%
 (1000 Mb/s)                                          STS-1-21v/VC-3-21v –98%

                                                                             59

                              Page 75 of reference
Inverse multiplexing in VCAT




 Implementation of VCAT is only required at select nodes (i.e.,
 the edge nodes); not all multiplexers need to support VCAT
                                                                  60

                      Page 82 of reference
Link Capacity Adjustment Scheme
              (LCAS)
• LCAS is a mechanism to allow for automatic
  bandwidth tuning of a virtually
  concatenated signal
  – The VCAT group of circuits should already be
    established using a
     • centralized NMS/EMS based procedure, or
     • by a distributed RSVP-TE based procedure
• Note that bandwidth cannot be increased
  beyond the aggregate value of the VCAT
  signal without a GMPLS RSVP or NMS/EMS
  procedure of circuit setup
                                                   61
 Link Capacity Adjustment Scheme
               (LCAS)
• LCAS is a synchronization procedure between the two ends
  of a VCAT signal
   – Unlike GMPLS RSVP, it is NOT a bandwidth reservation and
     circuit setup or release procedure
• LCAS procedures (triggered by GMPLS or NMS/EMS):
   – add or remove a member of a VCAT group
   – renumber the members in a VCAT group
• Messages are exchanged between the originating and
  terminating SONET/SDH nodes to execute these LCAS
  procedures
   – Add member (ChID, GID)
   – Remove member (ChID, GID)
   – Member status
• Messages are sent in the H4 byte for high-order VCAT
                                                                62
                 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

                                                          63
       Pseudo Wire Emulation
• Pseudo Wire Emulation Edge-to-Edge (PWE3) is a
  mechanism for emulating certain services across a
  packet-switched network:
   – Services: Frame-relay, ATM, Ethernet, TDM services,
     such as SONET/SDH
   – Packet-switched network:
      • IP
      • MPLS
   – Common usage: Ethernet service over MPLS
      • Port-mapped to MPLS LSP
      • VLAN mapped to MPLS LSP
   – IETF RFC 3985
          Digital wrapper
• ITU-T G. 709 provides a method to
  carry Ethernet frames, ATM cells, IP
  datagrams directly on a WDM
  lightpath




                                     65
                 Outline
• Principles
  – Different types of connection-oriented
    networks
• Technologies
  – Single network
  – Internetworking
Usage
  – Commercial networks
  – Research & Education Networks (REN)
                                             66
          Commercial uses
• Semi-permanent MPLS virtual circuits
  – Traffic engineering
  – Voice over IP
    • QoS concerns: telephony has a 150ms one-
      way delay requirement (with echo cancellers)
  – Business or service provider interconnect
    • interconnecting geographically distributed
      campuses of an enterprise
    • interconnecting wide-area routers of an ISP
      service provider
                                                 67
      Traffic engineering (TE)
• Since BGP and OSPF routing protocols mainly
  spread reachability information, routing tables are
  such that some links become heavily congested
  while others are lightly loaded
• MPLS virtual circuits are used to alleviate this
  problem
   – e.g., NY to SF traffic could be directed to take an MPLS
     virtual circuit on a lightly loaded route avoiding all paths
     on which more local traffic may compete
• This is an application of MPLS VCs without
  bandwidth allocation

                                                                68
 Goals of Traffic Engineering (TE)
• Monitor network resources and control traffic to
  maximize performance objectives
   – Goal of TE is to achieve efficient network operation with
     optimized resource utilization in an Autonomous System

• Goals of TE can be:
   – Traffic oriented
      • Enhance the QoS of traffic streams
      • Minimization of loss and delay
      • Maximization of throughput
   – Resource oriented
      • Load balancing
      • Minimize maximum congestion or minimize maximum
        resource utilization
      • Output – decreased packet loss and delay, increased
        throughput
                                                              69
  Business or service provider
         interconnect
• Multiple options:
  – TDM circuits (traditional private line, T1, T3,
    OC3, OC12, etc.)
  – Ethernet private line
     • point-to-point (Ethernet over MPLS/SONET/WDM)
     • VPNs (called Virtual private LAN service)
  – MPLS VPNs
  – WDM lightpaths
  – Dark fiber


                                                       70
Dynamic circuits/virtual circuit
    (GMPLS control-plane)
• Commercial:
  – fast restoration
     • circuit/VC setup delay significant
  – rapid provisioning
     • Verizon: Bandwidth on Demand (Just-in-Time
       Provisioning)
     • AT&T: Shared mesh networks
        – Customer Applications for dynamic network configuration
            » Key industries: Financial, Media & Entertainment
            » Corporate Utility Backbone Networks (e.g. reconfigure
              for disaster recovery)
            » Distribution of real-time content (e.g., Video)
     • Level3: Vyvx service
                                                              71
        Research & Education
         (G)MPLS networks
•   Internet2’s Dynamic Circuit network
•   NSF-funded DRAGON
•   DOE's ESnet - Science Data Network
•   DOE's Ultra Science Network (USN)
•   NSF-funded CHEETAH



                                      72
Internet2 DWDM network




                                                         Infinera
                                                       DWDM system
http://events.internet2.edu/speakers/speakers.php?go=people&id=178
                  Rick Summerhill talk (10/11/2007)
         Internet2
Dynamic Circuit (DC) network




                                                          Ciena CD-CI
                                                          Eth-SONET
                                                             switch
http://events.internet2.edu/speakers/speakers.php?go=people&id=178
                  Rick Summerhill talk (10/11/2007)
Internet2 IP-routed network
               IP-router-to-router links on one wavelength
            SONET switch-to-switch links on another wavelength




                                                             Ciena CD-CI
                                                             Eth-SONET
                                                                switch

                                                           Juniper
                                                        T640 IP router

 http://events.internet2.edu/speakers/speakers.php?go=people&id=178
                   Rick Summerhill talk (10/11/2007)
   Equipment at each PoP




http://events.internet2.edu/speakers/speakers.php?go=people&id=178
                  Rick Summerhill talk (10/11/2007)
     Control-plane software
        (for DC network)
• OSCARS implemented in InterDomain
  Controller (IDC) - one per domain
  – Abstracted topology exchange
  – Interdomain scheduling
  – Interdomain signaling (for provisioning)
• DRAGON (intradomain control-plane)
  – Used in Internet2’s DC network
  – Intradomain routing, path computation,
    signaling (for provisioning)
                                               77
                           OSCARS
• On-demand Secure Circuits and Advance Reservation
  System (OSCARS)
• DOE Office of Science and ESnet project
• Co-development with Internet2
• Web Service based provisioning infrastructure, which
  includes scheduling, AAA architecture using X.509
  certificates
     – Extended to include the DICE IDCP
     – Reservations held in SQL database
• Recall no support for book-ahead in GMPLS control protocols
• http://www.es.net/oscars/index.html


http://www.csm.ornl.gov/workshops/NetworkingResearchChallenges/agenda.html
                      Talk by Tom Lehman, Sep. 28, 2008                 78
                              DRAGON
•   Washington DC metro-area network:
     – Adva (old Movaz) WDM switches and Ethernet switches (G.709)
•   Control-plane software:
     – Network Aware Resource Broker – NARB
         • Intradomain listener, Path Computation
     – Virtual Label Swapping Router – VLSR
         • Implements OSPF-TE, RSVP-TE
         • Run on control PCs external to switches (since not all switches implement
           these GMPLS control-plane protocols)
         • Communicates with switches via SNMP, TL1, CLI to configure circuits.
     – Client System Agent – CSA
         • End system software for signaling into network (UNI or peer mode)
     – Application Specific Topology Builder – ASTB
         • User Interface and processing which build topologies on behalf of users
         • Topologies are a user specific configuration of multiple LSPs



                                                                                       79
                          http://dragon.east.isi.edu
                Open Source
             DCN Software Suite
• OSCARS (IDC)
     – Open source project maintained by ESNet and Internet2
     – Uses WDSL, XML, SQL database to store reservations
     – Reservations accepted with 1 minute granularity
• DRAGON (DC)
     – NSF-funded Open source project maintained by USC ISI
       EASTand MAX
• Version 0.4 of DCNSS current deployed release
     – https://wiki.internet2.edu/confluence/display/DCNSS
• DCN workshops offered for training:
     – http://www.internet2.edu/workshops/dcn/index.html



http://www.csm.ornl.gov/workshops/NetworkingResearchChallenges/agenda.html
                      Talk by Tom Lehman, Sep. 28, 2008                 80
                        DICE IDCP
• Dante, Internet2, CANARIE, ESNet
• http://www.controlplane.net
• IDCP: InterDomain Controller Protocol
• wsdl - web service definition of message
  types and formats
• xsd – definition of schemas used for
  network topology descriptions and path
  definitions

http://www.csm.ornl.gov/workshops/NetworkingResearchChallenges/agenda.html
                      Talk by Tom Lehman, Sep. 28, 2008                 81
            InterDomain Controller (IDC)
                  Protocol (IDCP)
•   The following organizations have implemented/deployed systems which are
    compatible with this IDCP
     –   Internet2 Dynamic Circuit Network (DCN)
     –   ESNet Science Data Network (SDN)
     –   GÉANT2 AutoBahn System
     –   Nortel (via a wrapper on top of their commercial DRAC System)
     –   Surfnet (via use of above Nortel solution)
     –   LHCNet (use of I2 DCN Software Suite)
     –   Nysernet (use of I2 DCN Software Suite)
     –   LEARN (use of I2 DCN Software Suite)
     –   LONI (use of I2 DCN Software Suite)
     –   Northrop Grumman (use of I2 DCN Software Suite)
     –   University of Amsterdam (use of I2 DCN Software Suite)
     –   DRAGON Network
•   The following "higher level service applications" have adapted their existing
    systems to communicate via the user request side of the IDCP:
     –    LambdaStation (FermiLab) – CMS project on Large Hadron Collider
     –   TeraPaths (Brookhaven) - ATLAS project on Large Hadron Collider
     –   Phoebus
http://www.csm.ornl.gov/workshops/NetworkingResearchChallenges/agenda.html
                      Talk by Tom Lehman, Sep. 28, 2008                 82
       Heterogeneous Network Technologies
            Complex End to End Paths
       Example: DRAGON                 Example: Internet2 DC
                                                           Example: ESNet SDN
                                       AS 2
          AS 1                    IP Control Plane                  AS 3
          IP Control Plane                                IP Control Plane


                                                                               VLSR

                                                     Router MPLS LSP
                                    Ethernet over
VLSR                                   SONET
              Ethernet over WDM                                      End
                                                                  System
                                     Ethernet
              End
             System                 Lambda Switch            Ethernet Segment
                                                           VLSR Established VLAN
                                    SONET Switch
   Ethernet Segment
 VLSR Established VLAN                Router

        http://events.internet2.edu/speakers/speakers.php?go=people&id=178
                          Rick Summerhill talk (10/11/2007)
                        IDCP operation
                                                                         Route selection,
                                                                         admission control
                                                                         centralized per
                                                                         domain at IDC




•   Advance reservation request and circuit provisioning at scheduled time:
     •   End user signals IDC with a reservation request
     •   Authenticate requester and check authorization
     •   Request reservation (create time, bandwidth, VLAN tag)
     •   Signaling: creation of circuit (automatic or in response to message to IDC)
•   Topology exchange: interdomain (abstracted topology information)
•   Monitoring
                                                                                       84
      http://hpn.east.isi.edu/dice-idcp/dice-idcp-v1.0/idc-protocol-specification-may302008.doc
     Intra-domain operations
• Using DRAGON in Internet2 DCN
  – NARB does intra-domain path computation after
    collecting routing information by listening to OSPF-TE
    exchanges between VLSRs
  – These intradomain paths are provided to IDC for use
    during resource scheduling (upto 3 path options are
    considered)
  – 5 VLSRs serve 22 CD-CIs: “subnets of CD-CIs”
  – In Signaling phase, VLSR sends TL1 command to edge CD-
    CI, which initiates proprietary hop-by-hop signaling to
    configure circuit through subnet



                                                         85
                                     86
GOLE: GLIF open lightpath exchange
               DOE networks
• ESnet and Science Data Network (SDN)
  – OSCARS: an advance-reservation system
  – Science Data Network: MPLS network
• UltraScience Network
  – Research network for DoE labs
  – GbE and SONET (Ciena CD-CI)
  – Centralized scheduler for advance-reservation calls
  – 5-PoP network: ORNL, Atlanta, Chicago, Seattle,
    Sunnyvale
  – Connections to Fermi Lab, PNNL, SLAC, CalTech
• Lambdastation: CMS project
  – Between Fermi Lab and Univ. of Nebraska
                                                          87
                NSF-funded CHEETAH network
                   GbEthernet and SONET
                                                                UVa
                    TN PoP                            GbE                         CUNY
                      SN16000        GbE
               OC192 Control GbE/        End hosts                    NCSU
               card  card    10GbE
                             card
                                                                               GbE
                                                                      GbEs


                                  OC-192
              GA PoP                                    NC PoP
                  SN16000                                   SN16000
          GbE GbE/
                    Control OC192
End   hosts   10GbE card                             OC192 Control GbE/ GbE
                            cards                                  10GbE
              card                                   card  card             End   hosts
                                                                   card

                                  OC-192                               GbE
              GbE                                                                    88
 ORNL                           Sycamore SN16000                             GaTech
                       SONET switch with GbE/10GbE interfaces
         Networking software
• Sycamore switch comes with built-in GMPLS
  control-plane protocols:
  – RSVP-TE and OSPF-TE
• We developed CHEETAH software for Linux
  end hosts:
   – circuit-requestor
     • allows users and applications to issue RSVP-TE
       call setup and release messages asking for
       dedicated circuits to remote end hosts
  – CircuitTCP (CTCP) code

            http://www.ece.virginia.edu/cheetah/   89
                                CHEETAH network usage

                                                                                                                 End Host
End Host                 CHEETAH                                                        CHEETAH
                         software                                                       software
                                                         IP-routed
                         DNS client                       network                       DNS client


                       RSVP-TE module                                               RSVP-TE module
Application                                         SONET circuit-                                             Application
                                                   switched network

              TCP/IP                                                                                 TCP/IP

                                      NIC 1    Circuit                Circuit   NIC 1
        CTCP/IP                               Gateway                Gateway                                  CTCP/IP
                                      NIC 2                                     NIC 2


           • Bandwidth-sharing mode:
                  •    Immediate-request mode
                  •    Heterogeneous rate allocation under high loads:
                        • higher BW for large files than for small files
           • Applications:
                  •    Common file transfers (web, P2P, CDN, storage)
                         •    attempts circuits for large files (if blocked, use IP-routed path)
                         •    use IP-routed path for small files                             90
             End-to-end call setup delay
                   measurements
•   Delays incurred in setting up a circuit between host zelda1 (in Atlanta, GA) and
    host wuneng (in Raleigh, NC) across the CHEETAH network

         Circuit type       End-to-end          Processing delay for        Processing delay for
                           circuit setup          Path message at             Resv message at
                             delay (s)          the NC SN16000 (s)          the NC SN16000 (s)
            OC-1             0.166103                 0.091119                   0.008689
            OC-3             0.165450                 0.090852                   0.008650
         1Gb/s EoS           1.645673                 1.566932                   0.008697
    Round-trip signaling message propagation plus emission delay between GA SN16000 and NC SN16000:
                                                   0.025s


•   Observations:
     –     Setup delays for SONET circuits (OC1, OC3) are small (166ms)
     –     Setup delays for Ethernet-over-SONET (EoS) hybrid circuits are much higher (1.6s)
           (no standard; proprietary implementation)
     –     Signaling message processing delays dominate end-to-end circuit setup delays

                                                                                                91
                Spectrum of services
                               New services

  Leased line    Verizon BoD       eScience      10G POTS          IP




Book-ahead mode                     Plain Old Telephone Service (64kbps)
Call duration specified             Immediate-Request (IR) mode
Current solution:                   Unspecified call duration
 • centralized per-domain path      Low call setup overhead
   computation/admission control         ( holding times can be shorter)
Low call handling volume            Distributed path computation/admission
     OSCARS/DRAGON                  control
                                    High call handling volume
                                                CHEETAH                 92
               Summary
• Principles
  – Different types of connection-oriented
    networks
• Technologies
  – Single network: MPLS, SONET, OTN
  – Internetworking: PWE3, GFP, G.709
• Usage
  – Commercial networks
  – Research & Education Networks (REN)
                                             93
    References on bandwidth sharing modes
•   X. Fang and M. Veeraraghavan, “On using a hybrid architecture for
    file transfers,” acceptedto IEEE Transactions on Parallel and
    Distributed Systems, 2009.
•   X. Zhu and M. Veeraraghavan, "Analysis and Design of Book-ahead
    Bandwidth-Sharing Mechanisms," IEEE Transactions on
    Communications, Dec. 08.
•   X. Fang and M. Veeraraghavan, On using circuit-switched networks
    for file transfers,” in IEEE Globecom, New Orleans, LA, Nov. 2008.
•   X. Zhu, M. E. McGinley, T. Li, and M. Veeraraghavan, "An Analytical
    Model for a Book-ahead Bandwidth Scheduler," in IEEE Globecom
    Washington, DC, Nov. 2007.
•   X. Zhu, X. Zheng, and M. Veeraraghavan, "Experiences in
    implementing an experimental wide-area GMPLS network," IEEE
    Journal on Selected Areas in Communications (JSAC), Apr. 2007.
•   M. Veeraraghavan, X. Fang, and X. Zheng, “On the suitability of
    applications for GMPLS networks,” in IEEE Globecom, San
    Francisco, CA, Nov. 2006.



                                                                          94
          References for OTN
• ITU-T G. 872 and G.709/Y.1331 Specifications
• T. Walker, “Optical Transport Network (OTN) Tutorial”,
  Available online: http://www.itu.int/ITU-
  T/studygroups/com15/otn/OTNtutorial.pdf
• Agilent, “An overview of ITU-T G.709,” Application Note
  1379
• P. Bonenfant and A. Rodriguez-Moral, "Optical Data
  Networking," IEEE Communications Magazine, Mar. 2000, pp.
  63-70.
• E. L. Varma, S. Sankaranarayanan, G. Newsome, Z.-W. Lin,
  and H. Esptein, “Architecting the Services Optical
  Network,” IEEE Communications Magazine, Sept. 2001, pp.
  80-87.

                                                         95
        References for OSPF-TE
•   RFC 2702 - Requirements for Traffic Engineering Over MPLS:
    http://www.faqs.org/rfcs/rfc2702.html
•   RFC 3630 - Traffic Engineering (TE) Extensions to OSPF Version 2:
    http://www.faqs.org/rfcs/rfc3630.html
•   RFC 4203 - OSPF Extensions in Support of Generalized Multi-Protocol Label
    Switching (GMPLS) : http://www.ietf.org/rfc/rfc4203.txt
•   RFC 2328 - OSPF Version 2 : http://www.ietf.org/rfc/rfc2328.txt
•   OSPFv2 Routing Protocols Extensions for ASON Routing:
    http://www.ietf.org/internet-drafts/draft-ietf-ccamp-gmpls-ason-routing-
    ospf-02.txt
•   RFC 4202 - Routing Extensions in Support of Generalized Multi-Protocol
    Label Switching (GMPLS): http://www.ietf.org/rfc/rfc4202.txt
•   RFC 3471- Generalized Multi-Protocol Label Switching (GMPLS) Signaling
    Functional Description: http://www.faqs.org/rfcs/rfc3471.html
•   Dimitri Papadimitriou, IETFInternet Draft, "OSPFv2 Routing Protocols
    Extensions for ASON Routing," draft-ietf-ccamp-gmpls-ason-routing-ospf-
    02.txt, October 2006.




                                                                           96
         Reference for
        GFP/VCAT/LCAS
• IEEE Communications Magazine, May
  2002, Special issue on "Generic
  Framing Procedure (GFP) and Data
  over SONET/SDH and OTN," Guest
  Editors, Tim Armstrong and Steven S.
  Gorshe
• 6 excellent papers


                                     97
 References for REN projects
• IEEE Communication Magazine special
  issue, March 2006
  – DRAGON, UltraScience Net, CHEETAH,
    several other projects




                                     98

				
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