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Versions: 00                                                            
Network Working Group                                         Vic Liu
Internet Draft                                            China Mobile
Intended status: Informational                          Bob Mandeville
                                                              Iometrix
                                                        Brooks Hickman
                                                Spirent Communications
                                                           Weiguo Hao
                                                   Huawei Technologies
                                                             Zu Qiang
                                                             Ericsson
Expires: January 2015                                    July 3, 2014




               Problem Statement for VxLAN Performance Test
                 draft-liu-nvo3-ps-vxlan-perfomance-00.txt




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Internet-Draft        PS for VxLAN Performance               July 2014


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Abstract

   As the number of data center tenant increased, 4K VLANs, mobility,
   broadcasting issues have become the network bottleneck. VxLAN has
   being take into consideration in China Mobile IDC.




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   There are two implementation solutions for VXLAN. The first one is
   that NVE resides in TOR (top of rack switch), another one is that
   NVE resides in V-Switch established in hypervisor of physical server.
   For virtualized network, it's much better to implement NVE in V-
   switch because it's directly connect with Virtual Machines and
   easier for business to carry on. As we research in VxLAN solution,
   some problems are take into our considerations. How much resources
   will be consumed by VxLAN in a virtualized network environment. This
   draft introduces the problem for VxLAN performance by test.

   There is no methodology which can effectively evaluate VxLAN
   forwarding performance. This draft also attempts to address this
   issue, give a VXLAN performance evaluation method, especially when
   VxLAN resides in the virtual switch.


Table of Contents


   1. Introduction ................................................ 3
   2. Consideration on VxLAN performanc ........................... 4
      2.1. Test methodology for VxLAN performance in virtual network 4
      2.2. Large-scale VxLAN test issues ........................... 4
      2.3. Key index in VxLAN performance .......................... 5
      2.4. Test Bed Setup ......................................... 5
      2.5. Benchmark test on virtualized network ................... 8
   3. Problem statement on VxLAN performance ....................... 9
      3.1. VxLAN performance on test bed ........................... 9
      3.2. VxLAN Scalable test issues ............................. 11
   4. Security Considerations ..................................... 11
   5. IANA Considerations ........................................ 11
   6. References ................................................. 11
      6.1. Normative References ................................... 11
      6.2. Informative References ................................. 11
   7. Acknowledgments ............................................ 12

1. Introduction

   As the number of data center tenant increased, 4K VLANs, mobility,
   broadcasting issues have become the network bottleneck. VxLAN has
   being take into consideration in China Mobile IDC.

   There are two implementation solutions for VXLAN. The first one is
   that NVE resides in TOR (top of rack switch), another one is that
   NVE resides in V-Switch established in hypervisor of physical server.
   For virtualized network, it's much better to implement NVE in V-
   switch because it's directly connect with Virtual Machines and


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   easier for business to carry on. As we research in VxLAN solution,
   some problems are take into our considerations. How much resources
   will be consumed by VxLAN in a virtualized network environment. This
   draft introduces the problem for VxLAN performance by test.

   There is no methodology which can effectively evaluate VxLAN
   forwarding performance. This draft also attempts to address this
   issue, give a VXLAN performance evaluation method, especially when
   VxLAN resides in the virtual switch.


2. Consideration on VxLAN performance

   While we testing performance on virtualized network, some issues and
   key index should be considered clearly.

   2.1. Test methodology for VxLAN performance in virtual network

   It's different from test for physical switch. Because firstly in
   virtual network, the DUT (VxLAN on V-switch), hypervisor and virtual
   test center (it's a VM) is all in one physical server. Secondly,
   it's not like RFC 2544 that the test center generate line rate
   traffic(usually 1G or 10G) and test the physical server's
   performance. As we generate traffic from one server to another
   (model A below), it has a fold point during traffic increase from 1G
   to 10G because the vCPU is overloading. For example, server A
   generate 1G traffic and server B can receive 100%, but server A
   generate 10G traffic and server B can only receive 530Mb traffic.

   So in this test, the test process is designed as follows:

     a) Firstly use the server to connect with a physical test center.

     b) Make a traffic benchmark of 128, 256, 512, 1024, 1518bytes.

     c) Setup the test bed this the benchmark to get performance
   without VxLAN.

     d) Setup VxLAN and running the same performance test.

   2.2. Large-scale VxLAN test issues

   When test the scale of VLANs, it can be simulate 4K VLAN on the test
   center. But, in virtual network, the virtual center is a virtual
   machine. And virtual machine can only establish one VxLAN with
   VSwitch. So it can't test the large scale VxLAN performance.



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   2.3. Key index in VxLAN performance

   a) CPU: CPU utilization is very important for VxLAN. However, vCPU
      can be allocated for VM. But it cannot allocated for hypervisor
      and VSwitch. We use the test methodology to evaluate the CPU
      performance for VxLAN.

   b) Memory: Memory is not sensitive from the test result. But we
      still think it should be listed as one VxLAN performance index.

   c) Latency: When traffic is forwarded between VM to VM across two
      different physical server. Latency should be an index.

   d) Throughput: We use the benchmark as the traffic throughput.

   e) Packet-lost: Virtual network may have few packet-lost because of
      unstable of vCPU. Less than 2% of packet-lost is acceptable.



2.4. Test Bed Setup

   The test bed includes two physical server with 10GE NIC, a test
   center, a 10GE TOR switch for test traffic and a 1GE TOR switch for
   management.

                   ----------------------
                  |Test Center PHY 10GE*2|
                   ----------------------
                            ||
                            ||
                       ----------
                 =====| 10GE TOR |=======
                ||     ----------       ||
                ||                      ||
                ||                      ||
       -------------------      -------------------
      |   --------------  |    |   --------------  |
      |  |V-switch(VTEP)| |    |  |V-switch(VTEP)| |
      |   --------------  |    |   --------------  |
      |      |       |    |    |      |       |    |
      |   -----     ----- |    |   -----     ----- |
      |  |TCVM1|   |TCVM2||    |  |TCVM1|   |TCVM2||
      |   -----     ----- |    |   -----     ----- |


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       -------------------      -------------------
           Server1                   Server2













































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   Two Dell server are R710XD (CPU: E5-2460) and R710 (CPU: E5-2430)
   with a pair of 10GE NIC. And in the server we allocate 2 vCPU and 8G
   memory to each Test Center Virtual Machine (TCVM).

   In traffic model A: We use a physical test center connect to each
   server to verify the benchmark of each server.

                         ----------------------
                        |Test Center PHY 10GE*2|
                         ----------------------
                                   ||
                                   ||
                           -------------------
                          |   --------------  |
                          |  |V-switch(VTEP)| |
                          |   --------------  |
                          |      |       |    |
                          |   -----     ----- |
                          |  |TCVM1|   |TCVM2||
                          |   -----     ----- |
                           -------------------
                               Server1

   In traffic model B: We use the traffic model A benchmark to test the
   performance of VxLAN.

                          ----------
                    =====| 10GE TOR |=======
                   ||     ----------       ||
                   ||                      ||
                   ||                      ||
          -------------------      -------------------
         |   --------------  |    |   --------------  |
         |  |V-switch(VTEP)| |    |  |V-switch(VTEP)| |
         |   --------------  |    |   --------------  |
         |      |       |    |    |      |       |    |
         |   -----     ----- |    |   -----     ----- |
         |  |TCVM1|   |TCVM2||    |  |TCVM1|   |TCVM2||
         |   -----     ----- |    |   -----     ----- |
          -------------------      -------------------
              Server1                   Server2







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2.5. Benchmark test on virtualized network

   The reason we need a benchmark test is we realized that the
   virtualized network is different from physical network device. We
   cannot use test methodology like RFC 2544. The performance is not
   linear growth with traffic we generate. It has an inflection point.

   To get the benchmark, we use traffic model A and get the result
   table below:

   Server 1: CPU E5-2430

    ------------------------------------------------------------
   | Byte| Rate(GE)| Server CPU MHZ |Server Mem| VM CPU| VM Mem|
    ------------------------------------------------------------
   |  0  |    0    |       505       |   3022   |  372  |  695  |
    ------------------------------------------------------------
   | 128 |  0.46   |      6085       |   3021   | 5836  |  695  |
    ------------------------------------------------------------
   | 256 |  0.84   |      6365       |   3021   | 6143  |  696  |
    ------------------------------------------------------------
   | 512 |  1.56   |      6330       |   3021   | 6099  |  696  |
    ------------------------------------------------------------
   | 1024|  2.88   |      5922       |   3021   | 5726  |  696  |
    ------------------------------------------------------------
   | 1518|  4.00   |      5713       |   3023   | 5441  |  696  |
    ------------------------------------------------------------


   Server 2: CPU E5-2620

   ------------------------------------------------------------
   | Byte| Rate(GE)| Server CPU MHZ |Server Mem| VM CPU| VM Mem|
    ------------------------------------------------------------
   |  0  |    0    |       505       |   2900   |  239  |  698  |
    ------------------------------------------------------------
   | 128 |  0.61   |      5631       |   2900   | 5117  |  698  |
    ------------------------------------------------------------
   | 256 |  0.94   |      5726       |   2896   | 5157  |  698  |
    ------------------------------------------------------------
   | 512 |  2.02   |      5786       |   2901   | 5217  |  698  |
    ------------------------------------------------------------
   | 1024|  4.02   |      5884       |   2901   | 5097  |  698  |
    ------------------------------------------------------------
   | 1518|  5.61   |      5856       |   2901   | 5197  |  698  |


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


   As we get the benchmark, we use the lower benchmark (server1) in
   traffic model B and test VxLAN performance.

3. Problem statement on VxLAN performance

3.1. VxLAN performance on test bed

   We use the lower benchmark (server 1) to generate traffic from
   server 1 to server 2 with VxLAN encapsulation and get the
   performance result of the two servers. And because of VxLAN
   encapsulation increases the packet length, to avoid MTU problem we
   use 1450 instead 1518 as original packet length.

   Server 1 with VxLAN: CPU E5-2430

    ------------------------------------------------------------
   | Byte| Rate(GE)| Server CPU MHZ |Server Mem| VM CPU| VM Mem|
    ------------------------------------------------------------
   |  0  |    0    |       515       |   3042   |  374  |  696  |
    ------------------------------------------------------------
   | 128 |  0.46   |      6395       |   3040   | 5748  |  696  |
    ------------------------------------------------------------
   | 256 |  0.84   |      6517       |   3042   | 5923  |  696  |
    ------------------------------------------------------------
   | 512 |  1.56   |      6668       |   3041   | 5857  |  696  |
    ------------------------------------------------------------
   | 1024|  2.88   |      6280       |   3043   | 5506  |  696  |
    ------------------------------------------------------------
   | 1450|  4.00   |      6233       |   3045   | 5309  |  696  |
    ------------------------------------------------------------
   Server 2: CPU E5-2620

   ------------------------------------------------------------
   | Byte| Rate(GE)| Server CPU MHZ |Server Mem| VM CPU| VM Mem|
    ------------------------------------------------------------
   |  0  |    0    |       450       |   2905   |  239  |  698  |
    ------------------------------------------------------------
   | 128 |  0.46   |      6203       |   2905   | 5897  |  698  |
    ------------------------------------------------------------
   | 256 |  0.84   |      5937       |   2906   | 5797  |  698  |
    ------------------------------------------------------------
   | 512 |  1.56   |      5993       |   2909   | 5737  |  698  |
    ------------------------------------------------------------
   | 1024|  2.88   |      5710       |   2912   | 5697  |  698  |


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    ------------------------------------------------------------
   | 1450|  4.00   |      5863       |   2902   | 5697  |  698  |
    ------------------------------------------------------------


   By analyzing the testing result, we have conclusion as follows:

   a) CPU: VxLAN function resided in VSwitch increases physical CPU
      usage. The table below shows the increasing percentage of CPU
      usage after using one VxLAN ID. The average increase is 6.51% in
      server 1 and 4.07% in server 2. This increase is cost by one VxLAN.
      We will still evaluate increase in large scale VxLAN scenario.

                 ----------------------------
                 | Byte| Server 1 | Server 2 |
                 ----------------------------
                 |  0  |  4.04%   |  24.65%  |
                 ----------------------------
                 | 128 |  7.57%   |  7.26%   |
                 ----------------------------
                 | 256 |  1.15%   |  7.59%   |
                 ----------------------------
                 | 512 |  8.66%   |  2.41%   |
                 ----------------------------
                 | 1024|  4.49%   |  0.14%   |
                 ----------------------------
                 | 1450|  11.61%  |  1.84%   |
                 ****************************
                 |*AVG |  6.51%   |  4.07%   |
                 ----------------------------


   b) Memory: Memory of both physical server and virtual machine are
      not sensitive during VxLAN test.

   c) Packet-loss: Because virtual network is based on X86 architecture.
      When vCPU utilizing rate reaches over 90%, there will be about 2%
      packet-loss. It is different with VXLAN on physical switch that no
      pack-lost forwarding is a necessary requirement.

   d) Line-rate forwarding: It is well known to us, in virtual network,
      traffic become unstable as CPU goes overload. Whatever we try, we
      can't reach line rate using any packet length. Finally, we reach
      10Gb using 1518 byte without VxLAN between two server by add 3
      pair of TCVM and each TCVM allocated 2 vCPU and 8G memory. While
      we add VxLAN and decrease 1518 to 1450(in case of fragment), on
      same network, we can only get 5.6 Gb unstable throughput.


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3.2. VxLAN Scalable test issues

   All the tests above are based on one VN. As we considering Multi-VN
   scenario. One problem we can't overlook is, the VSwitch can only
   recognize (or study) the VN ID from VNIC of VM (TCVM). As we
   generate thousands of VxLAN by the TCVM, none can be studied by
   VSwitch except the VxLAN to VNIC. We calculate, one VM can provide
   10 VNIC (MAX) which allocate 10 VxLAN, and one physical server
   install 20 VM. If we make a 5000VxLAN scale performance test, there
   will be at least 25 server.



 4.  Security Considerations



 5. IANA Considerations

 6. References



   6.1. Normative References

   [1]  Bradner, S., "Key words for use in RFCs to Indicate
         Requirement Levels", BCP 14, RFC 2119, March 1997.

   [2]  Crocker, D. and Overell, P.(Editors), "Augmented BNF for
         Syntax Specifications: ABNF", RFC 2234, Internet Mail
         Consortium and Demon Internet Ltd., November 1997.

   [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2234] Crocker, D. and Overell, P.(Editors), "Augmented BNF for
             Syntax Specifications: ABNF", RFC 2234, Internet Mail
             Consortium and Demon Internet Ltd., November 1997.

   6.2. Informative References

   [3]  Faber, T., Touch, J. and W. Yue, "The TIME-WAIT state in TCP
         and Its Effect on Busy Servers", Proc. Infocom 1999 pp. 1573-
         1583.



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   [Fab1999] Faber, T., Touch, J. and W. Yue, "The TIME-WAIT state in
             TCP and Its Effect on Busy Servers", Proc. Infocom 1999 pp.
             1573-1583.

 7. Acknowledgments

   <Add any acknowledgements>



Authors' Addresses

   Vic Liu
   China Mobile
   32 Xuanwumen West Ave, Beijing, China

   Email: liuzhiheng@chinamobile.com

   Bob Mandeville
   Iometrix
   3600 Fillmore Street
   Suite 409
   San Francisco, CA 94123
   USA
   bob@iometrix.com

   Brooks Hickman
   Spirent Communications
   1325 Borregas Ave
   Sunnyvale, CA 94089
   USA
   Brooks.Hickman@spirent.com

   Weiguo Hao
   Huawei Technologies
   101 Software Avenue, Nanjing 210012, China

   Email: haoweiguo@huawei.com

   Zu Qiang
   Ericsson
   8400, boul. Decarie
   Ville Mont-Royal, QC,
   Canada

   Email: Zu.Qiang@Ericsson.com



Vic Liu                Expires January 3, 2015               [Page 12]