Spirent Communications SmartFlow Quickstart Cisco by yaosaigeng


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  Spirent Communications

     SmartFlow Quickstart


May 2005
Evolution of Switching Technology

• A Multi-Layer switch performs all of the functions listed
  below.                             Increased intelligence

                             L2                             L3             L4+
   Bridge                                      VLAN
                            Switch                         Switch         Switch

               Figure 8-1. Evolution of Switching Technology

    80s           Early to Mid 90s            Mid 90s   Mid to Late 90s     Y2K

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The Need for QoS
•   IP is a "best-effort" protocol
    –    network does not guarantee how long it will take to send packets, what order they arrive in,
         or even if the sent data will reach it’s destination.

•   Real-time applications such as, voice and video are adversely affected by
    lost packets, delay, and delay variation (jitter).

•   On the lightly loaded network, these issues are not typically a problem.
    –    delay is minimal, jitter is not a factor because the delay is constant and packets are rarely
    –    These problems do become critical when the network becomes congested.

•   2 Possible solutions
          1. Design a network that will always have excess bandwidth so that it never gets
          2. Enable QoS

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What is QoS
• QoS is the ability of all layers of the network to cooperate and provide the
   performance that each application needs to meet user expectations.
    – QoS also allows network bandwidth to be used more efficiently
    – The goal is to deliver quality end-to-end service for user applications --
       including data, multimedia, and voice.

• QoS is characterized by a set of network performance metrics including:
    – Service availability - ability to gain access to the network.
    – Throughput - the rate at which packets are transmitted in a network; measured
       as average or peak rate.
    – Latency or Delay - the time it takes a packet to travel between the transmitting
       and receiving points on the network – one way or round trip.
    – Delay variation or jitter - the variation in time between all the packets in a
       stream or flow between endpoints.
    – Packet loss – the rate at which packets are discarded by the network.
    – Packet sequence – the ability of the network to deliver packets in proper
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How QoS is Implemented

• There are two main approaches to delivering QoS:
• Resource Reservation
    – eg. RSVP, MPLS ... signaling protocols which sets up an end-to-end path with
       specific QoS metrics. If such a path cannot be created, the connection is

• Traffic Prioritization (CoS, DiffServ, IP Precedence, )
    – Classifies each type of traffic according to the specific QoS Metrics that it
          • eg. traffic can be differentiated into High Priority (voice or real time data) and Low
                 Priority (file transfer or e-mail).

    – Each classification is mapped into a Per-hop Behavior (PHB)
          • PHB defines how each node in the network should treat the packet…
          • Nodes use queuing and congestion management algorithms eg. Weighted Fair
                 Queuing (WFQ) and Random Early Drop (RED)

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Testing All Layers

• The optimization of traffic can take place at layer 2, layer 3, layer 4, and
   even up to layer 7.
    – IEEE 802.1p (VLAN) (CoS) prioritizes traffic at layer 2 (Datalink).
    – DiffServ and TOS optimize resources at layer 3 (Network).
    – Server Load Balancers and traffic shaping optimize traffic based on TCP or
        UDP port number at layer 4 (transport).
    – Even higher-layer criteria such as URL or application type can be used (eg.
        CSM in Cat6K).

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IP Header: TOS Vs. Diffserv
• The TOS field in the IP header has been redefined and designated
    as DS (Differentiated Services or Diffserv for short).
                                                         8 bit TOS or DS field
                                            Precedence  D T R C Unused                                                 TOS
                                                 DSCP 6 bits   2 bit CU                                                DiffServ
IP Header                                                                                                              (MinDelay,MaxThrput,MaxReliability)
                                                                                                                       DSCP (Differentiated Services Code Point)
                                                                                                                       CU (Currently Unused)
0                                                                               15 16                                                                    31
                                                8 bit TOS or DS field
     4 bit          4 bit header
                                         Precedence    D T            R   Unused                     16 bit total length (in bytes)
    version            length
                                               DSCP 6 bits                2 bit CU

                            16 bit identification                                           3 bit                13 bit fragment offset

       8 bit time to live                           8 bit protocol                                    16 bit header checksum                                        20
             (TTL)                                                                                                                                                 bytes

                                                                      32 bit source IP address

                                                                     32 bit destination IP address


                                      Figure 7-30. IP header: TOS Vs. Diffserv
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Traditional Metrics
• Before converged networks, all we needed to know was how many
  frames per second could pass through a network.
• Scott Bradner of Harvard University devised tests to define the
  performance of traditional network devices.
    – These traditional metrics were defined in Bradner’s RFC 1242
      and RFC 1944 (later updated to RFC-2544).
    – These RFCs define tests for:
          •    Throughput - How many frames per second can be forwarded through a
              device before it starts losing frames.
          •    Packet Loss - How many packets per second are lost through a device
              at various throughput loads.
          •    Latency - What is the delay created by sending a packet through a
              network device under various load conditions?
          •    Traffic Bursts - Devices and networks can be very sensitive to bursts of
              traffic above the normal load. Most devices have memory buffers. This
              metric examines how a device copes with bursts of traffic.
• Traditional testing is necessary, but is no longer enough for
   today’s network.
    –    It does not measure QoS and the true user experience.
    –   testing must address individual traffic flows and streams.
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SmartMetrics Testing

• In today’s converged networks, many different applications are
    multiplexed onto a single device port, supporting voice,
    multimedia, data, and multicasting.

•   To test this network, the test must:
     – emulate many different types of traffic
     – determine the impact that different traffic types have on performance
     – determine the network’s ability to handle lightly loaded to fully loaded
       traffic conditions.

• To determine the true QoS, testing needs to address:
     1) Multiple network layers.
     2) Individual IP flows and streams.
     3) How new applications will effect the network before it goes “live”
     4) The transition between networking technologies.

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    What is SmartFlow?

An automated performance test suite
that determines:

•Throughput (no drop rate)
•Jumbo (Std Deviation of Latency (jitter))
•Frame Loss
•Latency Distribution
•Latency Snapshot (per packet Latency)
•SmartTracker (measures Frame Marking)

Supports GUI to Script
Results in XML, JPEG or CSV format

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Connecting to SMB – who to connect to (1/2)

                      Click on Setup, SmartBits Connection or hit CTRL-F8
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  Connecting to SMB – who to connect to (2/2)

 Add an IP Connection->type IP address
 of SMB chassis
 Use default Port of 16385

 Be sure you check mark only the
 chassis that you wish to connect to

•Serial for smb200/2000 only, use baud
rate of 38400

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Connect to SMB chassis

                                   Under Action, Connect, or hit F8
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SmartFlow -> Connect

                                                                           Number of
                                                                           chassis’ you
                                                                           connected to

  Note the Port Column. It has taken on the name that you set in the Connection
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SmartFlow Card Setup (1 of 2)

                                          Uncheck hides these columns

   •Model: Smartflow reads cards in chassis
   •Test Load: to specify specific load per port, or follow stepwise
   •Read State: Active (tx and Rx), Inactive (not used), Listen (not in
   Tx or Rx list)
   •Auto Negotiate: Disable or Force
   •Background: Payload of packet
   •Multiuser: Leave unchecked most of the time
   •Media type: active for dual media cards only
   •Speed and Duplex: Set these to what the other end is set to
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SmartFlow Card Setup (2 of 2)

•Multicast: IGMP version to use for this port (v1 or v2)
•MAC Address: The defaults are usually fine, but editable
•Address Resolution: check for L3 devices (ARP), uncheck for L2 or back to back
•Flow Control: Obey pause frames?
•Rx VLAN E-Type: Used for VLAN stacking (QinQ)

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SmartFlow IPv4 Networks Tab

  •Port IP Address: Port's IP address ( Layer 3 Setup)
  •Network: Specify the Network Portion
  •Gateway: IP address of the directly connected router port
  •Subnet Mask: Match the Mask to the directly connected router port
  •Wizard IP: This is the address that the Wizard will start with when creating Streams
  •VLAN ID: Are you using VLANs? If so, specify ID here
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 Multiple Networks per port (Network
•Right click on port you want multiple networks on
•Select Network Wizard

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SmartFlow IPv6 Networks Tab

                                           •Specify address format here

             •Like IPv4, except for IPv6
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SmartFlow-> Incrementing fields

   Easily Modify 100’s of ports with a few mouse clicks
   •Configure top row to values you want
   •Left Click on the Column Header, highlighting the Column.
     Right Click while your mouse is anywhere over the Column
   •You will get a Pop Up Box that allows easy configuration of the column
   •You can Copy Down, Fill and Increment, etc.
     This can be done with ANY column
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SmartFlow-> VLANs

                                  Starting VLAN ID

                                  How many VLANs for this

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Creating Traffic Streams Groups
             From Groups Tab, Click on Group Wizard

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SmartFlow Wizard - Traffic Pattern

                                  1.Select the type of Traffic you

                                  2. Click NEXT

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SmartFlow Wizard – Traffic

                                   Want to send traffic from all
                                      VLANs to destination port
                                      (many to one, or Backbone

                                   1. Select traffic source(s)
                                      (highlight first, hold <shft>,
                                      click last flow from that port .
                                      Check box
                                   2. Select destination port on B
                                   3. Click NEXT

                                     Note traffic direction
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SmartFlow Wizard - Flow

                                   Name group and Flows,
                                   If you want upper layer
                                   protocol, select here

                                    Select Frame length

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SmartFlow Wizard - Multiple Flows

                                   You can designate the flows
                                   that the Wizard creates as
                                   either ...
                                    • Non-cyclic flows with
                                      address variations (or a
                                      single, non-cyclic
                                      SmartFlow without address
                                      This option uses multiple

                                    • A single, cyclic SmartFlow
                                      (with address variations).

                                       This option uses one
                                    Default as shown… no
                                      incrementing addresses
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     Flows per Group

      This group has
      all these flows
      associated with it

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     Add Second Group

  Run Group
  Wizard again, but
  select flows from
  VLAN on second

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2 Groups Configured

               Now have 2
               groups, each with
               their own flows

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Test Setup Tab … Load and Duration

                                                   Set Traffic Load in %

    How long to send traffic for each iteration?
    This is for all tests
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  Test Setup Tab … other (Individual) tests
                                         Some tests have specific test

                                         These Tests are:
                                         1. Throughput
                                         2. Latency over Time
                                         3. Latency Snapshot

SmartTracker has it’s own Setup screen

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SmartFlow Run Tests

Run the tests you want…Jumbo runs Jitter, Frame Loss, Latency and Latency Distribution
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SmartFlow Sample Screen Shots-Chart

   •While the test is running you get a graph update after each iteration
   •Graphs can be saved in JPEG and HTML format
   •You can pick different ways to view the graph by using the right mouse button
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SmartFlow Sample Screen Shots-

                                   •Details tab will much more in depth information
                                   •This information can be exported in Excel or HTML format
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Result Reporting

• All Graphs can be exported to JPEG format
• All Spreadsheets can be exported to CSV
  (Comma Separated Value) format
• Everything can be exported or Emailed as a full
  or partial HTML report

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LAB Setup

                SMB-6000C                                              SMB-6000C

                         Station 1   Station 2            Station 3            Station 4

                         Station 5   Station 6            Station 7            Station 8

                         Station 9   Station 10           Station 11           Station 12

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   LAB… Station to IP address / port                                 mapping

Station 1                                       Station 3
Laptop IP address via DHCP                      Laptop IP address via DHCP
Connect to SMB                       Connect to SMB
Use ports 1A1 and 1A2                           Use ports 1A1 and 1A2
Router IP addresses (to 1A1)   Router IP addresses (to 1A1)
Router IP addresses (to 1A2)   Router IP addresses (to 1A2)

Station 2                                       Station 4
Laptop IP address via DHCP                      Laptop IP address via DHCP
Connect to SMB                       Connect to SMB
Use ports 1B1 and 1B2                           Use ports 1B1 and 1B2
Router IP addresses (to 1B1)   Router IP addresses (to 1B1)
Router IP addresses (to 1B2)   Router IP addresses (to 1B2)

Station 5                                       Station 7
Laptop IP address via DHCP                      Laptop IP address via DHCP
Connect to SMB                       Connect to SMB
Use ports 2A1 and 2A2                           Use ports 2A1 and 2A2
Router IP addresses (to 2A1)   Router IP addresses (to 2A1)
Router IP addresses (to 2A2)   Router IP addresses (to 2A2)

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   LAB… Station to IP address / port                                 mapping

Station 6                                       Station 8
Laptop IP address via DHCP                      Laptop IP address via DHCP
Connect to SMB                       Connect to SMB
Use ports 2B1 and 2B2                           Use ports 2B1 and 2B2
Router IP addresses (to 1A1)   Router IP addresses (to 1A1)
Router IP addresses (to 1A2)   Router IP addresses (to 1A2)

Station 9                                       Station 11
Laptop IP address via DHCP                      Laptop IP address via DHCP
Connect to SMB                       Connect to SMB
Use ports 3A1 and 3A2                           Use ports 3A1 and 3A2
Router IP addresses (to 1B1)   Router IP addresses (to 1B1)
Router IP addresses (to 1B2)   Router IP addresses (to 1B2)

Station 10                                      Station 12
Laptop IP address via DHCP                      Laptop IP address via DHCP
Connect to SMB                       Connect to SMB
Use ports 3B1 and 3B2                           Use ports 3B1 and 3B2
Router IP addresses (to 2A1)   Router IP addresses (to 2A1)
Router IP addresses (to 2A2)   Router IP addresses (to 2A2)

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                            Lab Setup Example

                                       Example for Station 1


       Port1A1                                                                        Port1A2

SrcIP (3…)                                                     SrcIP (3…)
DstIP (3…)                                                     DstIP (3…)
   GW                                                             GW

      QoS algorithm is IP Precedence Priority based Traffic-Shaping

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 Lab 1 SmartFlow

   Predict and verify, using SmartFlow, behavior of DUT with destination
     port oversubscribed
       • with no QoS enabled, then with QoS enabled
   Q. Without any type of QoS enabled on the DUT, what do you expect to
   Q. With QoS enabled on the DUT, what do you expect to see?

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Lab 1 SmartFlow - How
– Connect to SmartBits chassis
– Use defaults unless specified not to
– Reserve your cards (based on Station number assigned.. (see page 29)
Cards Tab... for each of your reserved ports
    • Check Multiuser in your port positions
    • no flow control or autonegotiation
    • 10Mbits Half Duplex
IPv4 Networks Tab … for each of your ports
    •   Port IP address 192.168.10X.2 (X is asigned page 30)
    •   Network is 192.168.10X.0
    •   Gateway is 192.168.10X.1
    •   Class C Subnet Mask
    •   Wizard IP…use defaults
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 Lab 1 Cont.
Click on Groups tab
Click on Group Wizard
   – make traffic pattern Backbone or Pair
      • In A box, check 2 lowest numbered port
      • In B box, check other port
      • Direction is A->B
      • Click on Next
      • in Group Prefix name, type DATA
      • in Flow Prefix name, type data
      • Check Generate Multiple Groups by box
           – radio button in TOS precedence
           – put checks in 0, 1, 3, 5, 7…click OK
      • set length to 512 bytes
      • Click Next, Click Finish
       (See next page for what it will look like when complete)
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Lab 1 Config Screen Shots

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  Lab 1 Cont.

• Click on SmartFlows tab
   – look at the different tabs under the SmartFlows tab
   (Note that IP addresses have been filled in automatically, used Wizard default
     values specified in Network setup under Card Setup tab)
• Click on Test Setup then, Test Iterations tab
   – Set DURATION to 5 seconds
   – Set LOAD to start at 10%, step by 10% stop at 100%
• Run the Jumbo test...Examine test results under Jumbo, Frame loss,
  Latency and Latency Variation… are they what you expected?
• Run the Latency over Time, using default values set in Test Setup ->
  Individual Tests tab
• Repeat above tests with QoS on the DUT turned on
• Examine test results…are they what you expected?
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