Subject: <draft-ietf-bmwg-mcastm-06.txt>

From: Kevin Dubray <[email-masked]>
Date: Mon, 30 Oct 2000 16:38:13 -0500

Network Working Group                            Hardev Soor 
INTERNET-DRAFT                                   Debra Stopp 
Expires in:  April 2001                          IXIA 
                                                  
                                                 Ralph Daniels 
                                                 Netcom Systems 
                                                 October 2000 

               Methodology for IP Multicast Benchmarking 
                    <draft-ietf-bmwg-mcastm-06.txt> 

Status of this Memo 
   
  This document is an Internet-Draft and is in  full  conformance  with 
  all provisions of Section 10 of RFC2026. 
   
  Internet-Drafts are working documents  of  the  Internet  Engineering 
  Task  Force  (IETF),  its  areas,  and its working groups.  Note that 
  other groups may  also  distribute  working  documents  as  Internet- 
  Drafts. 
   
  Internet-Drafts are draft documents valid for a maximum of six months 
  and  may be updated, replaced, or obsoleted by other documents at any 
  time.  It is inappropriate  to  use  Internet-  Drafts  as  reference 
  material or to cite them other than as "work in progress." 
   
  The  list   of   current   Internet-Drafts   can   be   accessed   at 
  http://www.ietf.org/ietf/1id-abstracts.txt 
   
  The list of Internet-Draft Shadow  Directories  can  be  accessed  at 
  http://www.ietf.org/shadow.html. 

Abstract 
   
  The purpose of this draft is to describe methodology specific to  the 
  benchmarking  of  multicast IP forwarding devices. It builds upon the 
  tenets set forth in RFC 2544, RFC 2432 and  other  IETF  Benchmarking 
  Methodology  Working  Group  (BMWG)  efforts.  This document seeks to 
  extend these efforts to the multicast paradigm. 
   
  The BMWG  produces  two  major  classes  of  documents:  Benchmarking 
  Terminology  documents  and  Benchmarking  Methodology documents. The 
  Terminology documents present the benchmarks and other related terms. 
  The  Methodology  documents define the procedures required to collect 
  the benchmarks cited in the corresponding Terminology documents. 

Soor, Stopp, & Daniels                                        [Page 1] 

INTERNET-DRAFT   Methodology for IP Multicast Benchmarking   Dec. 2000 

1 Introduction 
   
  This document defines a specific set of tests that vendors can use to 
  measure  and  report  the  performance characteristics and forwarding 
  capabilities of network devices that support IP multicast  protocols. 
  The results of these tests will provide the user comparable data from 
  different vendors with which to evaluate these devices. 
   
  A previous document, " Terminology for  IP  Multicast  Benchmarking" 
  (RFC 2432), defined many of the terms that are used in this document. 
  The terminology document should be  consulted  before  attempting  to 
  make use of this document. 
   
  This methodology will focus  on  one  source  to  many  destinations, 
  although  many of the tests described may be extended to use multiple 
  source to multiple destination IP multicast communication. 

2 Key Words to Reflect Requirements 
   
  The key words "MUST", "MUST NOT", "REQUIRED", "SHALL",  "SHALL  NOT", 
  "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in this 
  document are to be interpreted as described in RFC 2119. 

3 Test set up 
   
  Figure 1 shows a typical setup for an IP  multicast  test,  with  one 
  source  to  multiple  destinations,  although this MAY be extended to 
  multiple source to multiple destinations. 

                                                     +----------------+ 
                             +------------+          |                | 
          +--------+         |            |--------->| destination(1) | 
          |        |         |            |          |                | 
          | source |-------->|            |          +----------------+ 
          |        |         |            |          +----------------+ 
          +--------+         |   D U T    |--------->|                | 
                             |            |          | destination(2) | 
                             |            |          |                | 
                             |            |          +----------------+ 
                             |            |               . . . 
                             |            |          +----------------+ 
                             |            |          |                | 
                             |            |--------->| destination(n) | 
                             |            |          |                | 
                             |            |          +----------------+ 
                             |            | 
                             +------------+ 
   
                                 Figure 1 

Soor, Stopp, & Daniels                                        [Page 2] 

INTERNET-DRAFT   Methodology for IP Multicast Benchmarking   Dec. 2000 

  Generally , the destination ports first join the desired number of 
  multicast groups by sending IGMP Join Group messages to the DUT/SUT. 
  To verify that all destination ports successfully joined the 
  appropriate groups, the source port MUST transmit IP multicast frames 
  destined for these groups. The destination ports MAY send IGMP Leave 
  Group messages after the transmission of IP Multicast frames to clear 
  the IGMP table of the DUT/SUT. 
   
  In addition, all transmitted frames MUST contain a recognizable 
  pattern that can be filtered on in order to ensure the receipt of 
  only the frames that are involved in the test. 
   
  3.1    Test Considerations 
   
  3.2    IGMP Support 
       
  Each of the destination ports should support and be able to test all 
  IGMP versions 1, 2 and 3. The minimum requirement, however, is IGMP 
  version 2. 
   
  Each destination port should be able to respond to IGMP queries 
  during the test. 
   
  Each destination port should also send LEAVE (running IGMP version 2) 
  after each test. 
       
  3.3    Group Addresses 
       
  The Class D Group address SHOULD be changed between tests.  Many DUTs 
  have memory or cache that is not cleared properly and can bias the 
  results. 
   
  The following group addresses are recommended by use in a test: 
   
          224.0.1.27-224.0.1.255 
          224.0.5.128-224.0.5.255 
          224.0.6.128-224.0.6.255 
   
  If the number of group addresses accommodated by these ranges do not 
  satisfy the requirements of the test, then these ranges may be 
  overlapped. The total number of configured group addresses must be 
  less than or equal to the IGMP table size of the DUT/SUT.  
       
  3.4    Frame Sizes 
       
  Each test SHOULD be run with different Multicast Frame Sizes. The 
  recommended frame sizes are 64, 128, 256, 512, 1024, 1280, and 1518 
  byte frames. 
       
  3.5     TTL 

Soor, Stopp, & Daniels                                        [Page 3] 

INTERNET-DRAFT   Methodology for IP Multicast Benchmarking   Dec. 2000 

  The source frames should have a TTL value large enough to accommodate 
  the DUT/SUT. 

  3.6     Layer 2 Support 
       
  Each of the destination ports should support GARP/GMRP protocols to 
  join groups on Layer 2 DUTs/SUTs. 

4 Forwarding and Throughput 
   
  This section contains the description of the tests that are related 
  to the characterization of the packet forwarding of a DUT/SUT in a 
  multicast environment. Some metrics extend the concept of throughput 
  presented in RFC 1242. The notion of Forwarding Rate is cited in RFC 
  2285. 
   
  4.1    Mixed Class Throughput 
   
  Objective 
   
  To determine the maximum throughput rate at which none of the offered 
  frames, comprised from a unicast Class and a multicast Class, to be 
  forwarded are dropped by the device across a fixed number of ports as 
  defined in RFC 2432. 
   
  Procedure 
   
   Multicast and unicast traffic are mixed together in the same 
   aggregated traffic stream in order to simulate the non-homogenous 
   networking environment. While the multicast traffic is transmitted 
   from one source to multiple destinations, the unicast traffic MAY be 
   evenly distributed across the DUT/SUT architecture. In addition, the 
   DUT/SUT SHOULD learn the appropriate unicast IP addresses, either by 
   sending ARP frames from each unicast address, sending a RIP packet or 
   by assigning static entries into the DUT/SUT address table. 
    
   The mixture of multicast and unicast traffic MUST be set up in one of 
   two ways: 
    
          a) As a percentage of the total traffic flow employing maximum 
          bandwidth utilization. Thus, each type of traffic is 
          transmitted at the maximum available bandwidth. This also 
          implies that the offered load, regardless of the type of 
          traffic, remains constant. 
           
          b) As a percentage of the total traffic flow employing a 
          proportionate bandwidth utilization. Thus, each type of 
          traffic is transmitted at a fraction of the available 
          bandwidth proportional to the specified ratio. This also 
          implies that the offered load for each traffic type varies in 
          proportion to its specified ratio. 

Soor, Stopp, & Daniels                                        [Page 4] 

INTERNET-DRAFT   Methodology for IP Multicast Benchmarking   Dec. 2000 

  The transmission of the frames MUST be set up so that they form a 
  deterministic distribution while still maintaining the specified 
  forwarding rates. See Appendix A for a discussion on non-homogenous 
  vs. homogenous packet distribution. 
   
  Similar to the Frame loss rate test in RFC 2544, the first trial 
  SHOULD be run for the frame rate that corresponds to 100% of the 
  maximum rate for the frame size on the input media. Repeat the 
  procedure for the rate that corresponds to 90% of the maximum rate 
  used and then for 80% of this rate. This sequence SHOULD be continued 
  (at reducing 10% intervals) until there are two successive trials in 
  which no frames are lost. The maximum granularity of the trials MUST 
  be 10% of the maximum rate, a finer granularity is encouraged. 
   
  Result 
   
  Parameters to be measured SHOULD include the frame loss and percent 
  loss for each class of traffic per destination port.  The ratio of 
  unicast traffic to multicast traffic MUST be reported. 
   
  In addition, the transmit and receive rates in frames per second for 
  each source and destination port for both unicast and multicast 
  traffic, together with the number of frames transmitted and received 
  per port per class type traffic SHOULD be reported. 

  4.2    Scaled Group Forwarding Matrix 
   
  Definition 
   
  A table that demonstrates Forwarding Rate as a function of tested 
  multicast groups for a fixed number of tested DUT/SUT ports. 
   
  Procedure 
   
  Multicast traffic is sent at a fixed percent of maximum offered load 
  with a fixed number of receive ports of the tester at a fixed frame 
  length. 
   
  The receive ports SHOULD continue joining incrementally by 10 
  multicast groups until a user defined maximum is reached. 
   
  The receive ports will continue joining in the incremental fashion 
  until a user defined maximum is reached. 
   
  Results 
   
  Parameters to be measured SHOULD include the frame loss and percent 
  loss per destination port for each multicast group address. 
   
  In addition, the transmit and receive rates in frames per second for 
  each source and destination port for all multicast groups, together 

Soor, Stopp, & Daniels                                        [Page 5] 

INTERNET-DRAFT   Methodology for IP Multicast Benchmarking   Dec. 2000 

  with the number of frames transmitted and received per port per 
  multicast groups SHOULD be reported. 
   
  4.3    Aggregated Multicast Throughput 
   
  Definition 
   
  The maximum rate at which none of the offered frames to be forwarded 
  through N destination interfaces of the same multicast group are 
  dropped. 
   
  Procedure 
   
  Multicast traffic is sent at a fixed percent of maximum offered load 
  with a fixed number of groups at a fixed frame length for a fixed 
  duration of time. 
   
  The initial number of receive ports of the tester will join the 
  group(s) and the sender will transmit to the same groups after a 
  certain delay (a few seconds). 
   
  Then the an incremental number of receive ports will join the same 
  groups and then the Multicast traffic is sent as stated. 
   
  The receive ports will continue to be added and multicast traffic 
  sent until a user defined maximum number of ports is reached. 
   
  Results 
   
  Parameters to be measured SHOULD include the frame loss and percent 
  loss per destination port for each multicast group address. 
   
  In addition, the transmit and receive rates in frames per second for 
  each source and destination port for all multicast groups, together 
  with the number of frames transmitted and received per port per 
  multicast groups SHOULD be reported. 
   
  4.4    Encapsulation (Tunneling) Throughput 
   
  This sub-section provides the description of tests that help in 
  obtaining throughput measurements when a DUT/SUT or a set of DUTs are 
  acting as tunnel endpoints. The following Figure 2 presents the 
  scenario for the tests. 
   
     Client A      DUT/SUT A      Network      DUT/SUT B      Client B 

                ----------                   ---------- 

                |        |      ------       |        | 

   -----(a)  (b)|        |(c)  (      )   (d)|        |(e) (f)----- 

   ||||| -----> |        |---->(      )----->|        |-----> ||||| 

   -----        |        |      ------       |        |       ----- 

                |        |                   |        | 

Soor, Stopp, & Daniels                                        [Page 6] 

INTERNET-DRAFT   Methodology for IP Multicast Benchmarking   Dec. 2000 

                ----------                   ---------- 

                                Figure 2 

                                -------- 

  A tunnel is created between DUT/SUT A (the encapsulator) and DUT/SUT 
  B (the decapsulator). Client A is acting as a source and Client B is 
  the destination. Client B joins a multicast group (for example, 
  224.0.1.1) and it sends an IGMP Join message to DUT/SUT B to join 
  that group. Client A now wants to transmit some traffic to Client B. 
  It will send the multicast traffic to DUT/SUT A which encapsulates 
  the multicast frames, sends it to DUT/SUT B which will decapsulate 
  the same frames and forward them to Client B. 
   
  4.4.1      Encapsulation Throughput 
       
     Definition 
       
     The maximum rate at which frames offered a DUT/SUT are 
     encapsulated and correctly forwarded by the DUT/SUT without loss. 
       
     Procedure 
       
      To test the forwarding rate of the DUT/SUT when it has to go 
      through the process of encapsulation, a test port B is injected at 
      the other end of DUT/SUT A (Figure B) that will receive the 
      encapsulated frames and measure the throughput. Also, a test port 
      A is used to generate multicast frames that will be passed through 
      the tunnel. 
       
      The following is the test setup: 
       
      Test port A     DUT/SUT A              Test port B 
       
                     ---------- (c')      (d')--------- 
                     |        |-------------->|       | 
      -------(a)  (b)|        |               |       | 
      ||||||| -----> |        |      ------   --------- 
      -------        |        |(c)  ( N/W  ) 
                     |        |---->(      ) 
                     ----------      ------ 
                                   Figure 3 
                                   -------- 
       
      In Figure 2, a tunnel is created with the local IP address of 
      DUT/SUT A as the beginning of the tunnel (point c) and the IP 
      address of DUT/SUT B as the end of the tunnel (point d). DUT/SUT B 
      is assumed to have the tunneling protocol enabled so that the 
      frames can be decapsulated. When the test port B is inserted in 
      between the DUT/SUT A and DUT/SUT B (Figure 3), the endpoint of 
      tunnel has to be re-configured to be directed to the test port B's 
      IP address. For example, in Figure 3, point c' would be  assigned 

Soor, Stopp, & Daniels                                        [Page 7] 

INTERNET-DRAFT   Methodology for IP Multicast Benchmarking   Dec. 2000 

      as the beginning of the tunnel and point d' as the end of the 
      tunnel. The test port B is acting as the end of the tunnel, and it 
      does not have to support any tunneling protocol since the frames 
      do not have to be decapsulated. Instead, the received encapsulated 
      frames are used to calculate the throughput and other necessary 
      measurements. 
       
      Result 
       
      Parameters to be measured SHOULD include the frame loss and 
      percent loss per destination port for each multicast group 
      address. 
       
      In addition, the transmit and receive rates in frames per second 
      for each source and destination port for all multicast groups, 
      together with the number of frames transmitted and received per 
      port per multicast groups SHOULD be reported. 
   
  4.4.2      Decapsulation Throughput 
       
     Definition 
       
      The maximum rate at which frames offered a DUT/SUT are 
      decapsulated and correctly forwarded by the DUT/SUT without loss. 
       
      Procedure 
       
      The decapsulation process returns the tunneled unicast frames back 
      to their multicast format. This test measures the throughput of 
      the DUT/SUT when it has to perform the process of decapsulation, 
      therefore, a test port C is used at the end of the tunnel to 
      receive the decapsulated frames (Figure 4). 
       
      Test port A  DUT/SUT A    Test port B     DUT/SUT B   Test port C 
       
                   ----------                 ---------- 
                   |        |                 |        | 
      -----(a)  (b)|        |(c)   ----    (d)|        |(e) (f)----- 
      ||||| -----> |        |----> |||| ----->|        |-----> ||||| 
      -----        |        |      ----       |        |       ----- 
                   |        |                 |        | 
                   ----------                 ---------- 
       
                                  Figure 4 
                                  -------- 
       
      In Figure 4, the encapsulation process takes place in DUT/SUT A. 
      This may effect the throughput of the DUT/SUT B. Therefore, two 
      test ports should be used to separate the encapsulation and 
      decapsulation processes. Client A is replaced with the test port A 
      which will generate a multicast frame that will be encapsulated by 
      DUT/SUT A. Another test port B is inserted between DUT/SUT A and 
      DUT/SUT B that will also receive the encapsulated frames as they 
  
Soor, Stopp, & Daniels                                        [Page 8] 

INTERNET-DRAFT   Methodology for IP Multicast Benchmarking   Dec. 2000 

      are forwarded by DUT/SUT A to DUT/SUT B. Test port B may be used 
      to monitor the throughput of the encapsulated frames as they 
      traverse the tunnel. Test port C will receive the decapsulated 
      frames and measure the throughput. 
       
      Result 
       
      Parameters to be measured SHOULD include the frame loss and 
      percent loss per destination port for each multicast group 
      address. 
       
      In addition, the transmit and receive rates in frames per second 
      for each source and destination port for all multicast groups, 
      together with the number of frames transmitted and received per 
      port per multicast groups SHOULD be reported. 

  4.4.3      Re-encapsulation Throughput 
       
     Definition 
       
      The maximum rate at which frames of one encapsulated format 
      offered a DUT/SUT are converted to another encapsulated format and 
      correctly forwarded by the DUT/SUT without loss. 
       
      Procedure 
       
      Re-encapsulation takes place in DUT/SUT B after test port C has 
      received the decapsulated frames. These decapsulated frames will 
      be re-inserted with a new encapsulation frame and sent to test 
      port B which will measure the throughput. See Figure 5. 
       
         Test port A   DUT/SUT A    Test port B   DUT/SUT B  Test port 
  C 
   
                       ----------                 ---------- 
                       |        |                 |        | 
          -----(a)  (b)|        |(c)   ----    (d)|        |(e) (f)----
  - 
          ||||| -----> |        |----> |||| <---->|        |<----> 
  ||||| 
          -----        |        |      ----       |        |       ----
  - 
                       |        |                 |        | 
                       ----------                 ---------- 
   
                                  Figure 5 
                                  -------- 
      Result 
       
      Parameters to be measured SHOULD include the frame loss and 
      percent loss per destination port for each multicast group 
      address. 
  
Soor, Stopp, & Daniels                                        [Page 9] 

INTERNET-DRAFT   Methodology for IP Multicast Benchmarking   Dec. 2000 

      In addition, the transmit and receive rates in frames per second 
      for each source and destination port for all multicast groups, 
      together with the number of frames transmitted and received per 
      port per multicast groups SHOULD be reported. 

       
5 Forwarding Latency 
   
  This section presents methodologies relating to the characterization 
  of the forwarding latency of a DUT/SUT in a multicast environment. It 
  extends the concept of latency characterization presented in RFC 
  2544. 
   
  5.1    Multicast Latency 
   
  Definition 
   
  The set of individual latencies from a single input port on the 
  DUT/SUT or SUT to all tested ports belonging to the destination 
  multicast group. 
   
  Procedure 
   
  According to RFC 2544, a tagged frame is sent half way through the 
  transmission that contains a timestamp used for calculation of 
  latency. In the multicast situation, a tagged frame is sent to all 
  destinations for each multicast group and latency calculated on a per 
  multicast group basis.  
   
  Note that this test MUST be run using the transmission rate that is 
  less than the multicast throughput of the DUT/SUT.  In addition,  the 
  transmission rate SHOULD be less than the rate at which the buffers 
  are depleted in order to avoid measuring buffer depth. The test 
  should also take into account the DUT's/SUT's need to cache the 
  traffic in its IP cache, fastpath cache or shortcut tables since the 
  initial part of the traffic will be utilized to build these tables. 
   
  Result 
   
  The parameter to be measured is the latency value for each multicast 
  group address per destination port. An aggregate latency MAY also be 
  reported.  In addition, the transmit rate in frames per second for 
  each source port SHOULD be reported. 

  5.2    Min/Max/Average Multicast Latency 
   
  Definition 
  
Soor, Stopp, & Daniels                                       [Page 10] 

INTERNET-DRAFT   Methodology for IP Multicast Benchmarking   Dec. 2000 

  The difference between the maximum latency measurement and the 
  minimum latency measurement from the set of latencies produced by the 
  Multicast Latency benchmark. 
   
  Procedure 
   
  First determine the throughput for DUT/SUT at each of the listed 
  frame sizes determined by the forwarding and throughput tests of 
  section 4. Send a stream of frames to a fixed number of multicast 
  groups through the DUT at the determined throughput rate. An 
  identifying tag SHOULD be included in all frames to ensure proper 
  identification of the transmitted frame on the receive side, the type 
  of tag being implementation dependent.  
   
  Latencies for each transmitted frame are calculated based on the 
  description of latencies in RFC 2544.  The average latency is the 
  total of all accumulated latency values divided by the total number 
  of those values.  The minimum latency is the smallest latency; the 
  maximum latency is the largest latency of all accumulated latency 
  values. 
  
  Note that this test MUST be run using the transmission rate that is 
  less than the multicast throughput of the DUT/SUT.  In addition,  the 
  transmission rate SHOULD be less than the rate at which the buffers 
  are depleted in order to avoid measuring buffer depth. The test 
  should also take into account the DUT's/SUT's need to cache the 
  traffic in its IP cache, fastpath cache or shortcut tables since the 
  initial part of the traffic will be utilized to build these tables. 
   
  Results 
   
  The parameters to be measured are the minium, maximum and average 
  latency values for each multicast group address per destination port. 
  In addition, the transmit rate in frames per second for each source 
  port SHOULD be reported. 
   
6 Overhead 
   
  This section presents methodology relating to the characterization of 
  the overhead delays associated with explicit operations found in 
  multicast environments. 
   
  6.1    Group Join Delay 
   
  Definition 
   
  The time duration it takes a DUT/SUT to start forwarding multicast 
  packets from the time a successful IGMP group membership report has 
  been issued to the DUT/SUT. 
   
  Procedure 

Soor, Stopp, & Daniels                                       [Page 11] 

INTERNET-DRAFT   Methodology for IP Multicast Benchmarking   Dec. 2000 

  Traffic is sent on the source port at the same time as the IGMP JOIN 
  Group message is transmitted from the destination ports.  The join 
  delay is the difference in time from when the IGMP Join is sent 
  (timestamp A) and the first frame is forwarded to a receiving member 
  port (timestamp B). 
   
            Group Join delay = timestamp B - timestamp A 
   
  One of the keys is to transmit at the fastest rate the DUT/SUT can 
  handle multicast frames.  This is to get the best resolution and the 
  least margin of error in the Join Delay.  
   
  However, you do not want to transmit the frames so fast that frames 
  are dropped by the DUT/SUT. Traffic should be sent at the throughput 
  rate determined by the forwarding tests of section 4. 
   
  Results 
   
  The parameter to be measured is the join delay time for each 
  multicast group address per destination port. In addition, the number 
  of frames transmitted and received and percent loss may be reported. 
   
  6.2    Group Leave Delay 
   
  Definition 
   
  The time duration it takes a DUT/SUT to cease forwarding multicast 
  packets after a corresponding IGMP "Leave Group" message has been 
  successfully offered to the DUT/SUT. 
   
  Procedure 
   
  Traffic is sent on the source port at the same time as the IGMP Leave 
  Group messages are transmitted from the destination ports.  The leave 
  delay is the difference in time from when the IGMP leave is sent 
  (timestamp A) and the last frame is forwarded to a receiving member 
  port (timestamp B). 
   
            Group Leave delay = timestamp B - timestamp A 
   
  One of the keys is to transmit at the fastest rate the DUT/SUT can 
  handle multicast frames.  This is to get the best resolution and 
  least margin of error in the Leave Delay.  However, you do not want 
  to transmit the frames too fast that frames are dropped by the 
  DUT/SUT.  Traffic should be sent at the throughput rate determined by 
  the forwarding tests of section 4. 
   
  Result 
   
  The parameter to be measured is the leave delay time for each 
  multicast group address per destination port. In addition, the number 
  of frames transmitted and received and percent loss may be reported. 

Soor, Stopp, & Daniels                                       [Page 12] 

INTERNET-DRAFT   Methodology for IP Multicast Benchmarking   Dec. 2000 

7 Capacity 
   
  This section offers terms relating to the identification of multicast 
  group limits of a DUT/SUT. 
   
  7.1    Multicast Group Capacity 
   
  Definition 
   
  The maximum number of multicast groups a DUT/SUT can support while 
  maintaining the ability to forward multicast frames to all multicast 
  groups registered to that DUT/SUT. 
   
  Procedure 
   
  One or more destination ports of DUT/SUT will join an initial number 
  of groups.  
   
  Then after a delay (enough time for all ports to join) the source 
  port will transmit to each group at a transmission rate that the 
  DUT/SUT can handle without dropping IP Multicast frames. 
   
  If all frames sent are forwarded by the DUT/SUT and received the test 
  iteration is said to pass at the current capacity. 
   
  If the iteration passes at the capacity the test will add an user 
  defined incremental value of groups to each receive port. 
   
  The iteration is to run again at the new group level and capacity 
  tested as stated above. 
   
  Once the test fails at a capacity the capacity is stated to be the 
  last Iteration that pass at a giving capacity. 
   
  Results 
   
  The parameter to be measured is the total number of group addresses 
  that were successfully forwarded with no loss. 

8 Interaction 
   
  Network forwarding devices are generally required to provide more 
  functionality than just the forwarding of traffic.  Moreover, network 
  forwarding devices may be asked to provide those functions in a 
  variety of environments.  This section offers terms to assist in the 
  characterization of DUT/SUT behavior in consideration of potentially 
  interacting factors. 
   
  8.1    Forwarding Burdened Multicast Latency 

Soor, Stopp, & Daniels                                       [Page 13] 

INTERNET-DRAFT   Methodology for IP Multicast Benchmarking   Dec. 2000 

  The Multicast Latency metrics can be influenced by forcing the 
  DUT/SUT to perform extra processing of packets while multicast 
  traffic is being forwarded for latency measurements. In this test, a 
  set of ports on the tester will be designated to be source and 
  destination similar to the generic IP Multicast test setup. In 
  addition to this setup, another set of ports will be selected to 
  transmit some multicast traffic that is destined to multicast group 
  addresses that have not been joined by these additional set of ports.  
   
  For example, if ports 1,2, 3, and 4 form the burdened response setup 
  (setup A) which is used to obtain the latency metrics and ports 5, 6, 
  7, and 8 form the non-burdened response setup (setup B) which will 
  afflict the burdened response setup, then setup B traffic will join 
  multicast group addresses not joined by the ports in this setup.  By 
  sending such multicast traffic, the DUT/SUT will perform a lookup on 
  the packets that will affect the processing of setup A traffic. 
   
  8.2    Forwarding Burdened Group Join Delay 
   
  The port configuration in this test is similar to the one described 
  in section 8.1, but in this test, the multicast traffic is not sent 
  by the ports in setup B. In this test, the setup A traffic must be 
  influenced in such a way that will affect the DUT's/SUT's ability to 
  process Group Join messages. Therefore, in this test, the ports in 
  setup B will send a set of IGMP Group Join messages while the ports 
  in setup A are also joining its own set of group addresses. Since the 
  two sets of group addresses are independent of each other, the group 
  join delay for setup A may be different than in the case when there 
  were no other group addresses being joined. 

9 Security Considerations 
   
  As this document is solely for the purpose of providing metric 
  methodology and describes neither a protocol nor a protocol's 
  implementation, there are no security considerations associated with 
  this document. 

10 
  References 

[Br91] Bradner, S., "Benchmarking Terminology for Network 
       Interconnection Devices", RFC 1242, July 1991. 
 
[Br96] Bradner, S., and J. McQuaid, "Benchmarking Methodology for 
       Network Interconnect Devices", RFC 2544, March 1999. 
 
[Br97] Bradner, S. "Use of Keywords in RFCs to Reflect Requirement 
       Levels, RFC 2119, March 1997 
 
[Du98] Dubray, K., "Terminology for IP Multicast Benchmarking", RFC 
       2432, October 1998. 
  
Soor, Stopp, & Daniels                                       [Page 14] 

INTERNET-DRAFT   Methodology for IP Multicast Benchmarking   Dec. 2000 

[Hu95] Huitema, C.  "Routing in the Internet."  Prentice-Hall, 1995. 
 
[Ka98] Kosiur, D., "IP Multicasting: the Complete Guide to Interactive 
       Corporate Networks", John Wiley & Sons, Inc, 1998. 
 
[Ma98] Mandeville, R., "Benchmarking Terminology for LAN Switching 
       Devices", RFC 2285, February 1998. 
 
[Mt98] Maufer, T.  "Deploying IP Multicast in the Enterprise." Prentice-
       Hall, 1998. 
 
[Se98] Semeria, C. and Maufer, T.  "Introduction to IP Multicast 
       Routing."  http://www.3com.com/nsc/501303.html  3Com Corp., 1998. 

Soor, Stopp, & Daniels                                       [Page 15] 

INTERNET-DRAFT   Methodology for IP Multicast Benchmarking   Dec. 2000 

11 
  Author's Addresses 
   
  Hardev Soor 
  IXIA 
  26601 W. Agoura Rd. 
  Calabasas, CA  91302 
  USA  
   
  Phone: 818 871 1800 
  EMail: [email-masked] 

  Debra Stopp 
  IXIA 
  26601 W. Agoura Rd. 
  Calabasas, CA  91302 
  USA  
   
  Phone: 818 871 1800 
  EMail: [email-masked] 

  Ralph Daniels 
  Netcom Systems 
  948 Loop Road 
  Clayton, NC 27520 
  USA 
   
  Phone: 919 550 9475 
  EMail: [email-masked] 

Soor, Stopp, & Daniels                                       [Page 16] 

INTERNET-DRAFT   Methodology for IP Multicast Benchmarking   Dec. 2000 

Appendix A: Determining an even distribution 
   
  It is important to understand and fully define the distribution of 
  frames among all multicast and unicast destinations.  If the 
  distribution is not well defined or understood, the throughput and 
  forwarding metrics are not meaningful. 
   
  In a homogeneous environment, a large single burst of multicast 
  frames may be followed by a large burst of unicast frames. This is a 
  very different distribution than that of a non-homogeneous 
  environment, where the multicast and unicast frames are intermingled 
  throughout the entire transmission. 
   
  The recommended distribution is that of the non-homogeneous 
  environment because it more closely represents a real-world scenario. 
  The distribution is modeled by calculating the number of multicast 
  frames per destination port as a burst, then calculating the number 
  of unicast frames to transmit as a percentage of the total frames 
  transmitted. The overall effect of the distribution is small bursts 
  of multicast frames intermingled with small bursts of unicast frames. 

12 
  Full Copyright Statement 

  "Copyright (C) The Internet Society (date). All Rights Reserved. This 
  document and translations of it may be copied and furnished to 
  others, and derivative works that comment on or otherwise explain it 
  or assist in its implementation  may be prepared, copied, published 
  and distributed, in whole or in part, without restriction of any 
  kind, provided that the above copyright notice and this paragraph are 
  included on all such copies and derivative works. However, this 
  document itself may not be modified in any way, such as by removing 
  the copyright notice or references to the Internet Society or other 
  Internet organizations, except as needed for the purpose of 
  developing Internet standards in which case the procedures for 
  copyrights defined in the Internet Standards process must be 
  followed, or as required to translate it into. 

Soor, Stopp, & Daniels                                       [Page 17]