TWAMP and TWAMP light

TWAMP(Two-Way Active Measurement Protocol,双向主动测量协议)是一种用于IP链路的网络质量测量技术,它使用UDP报文测量网络双向路径时延、抖动及丢包率。TWAMP-light是TWAMP协议的轻量级架构,简化了建立性能测量会话的控制协议,提高了测试性能。

如下TWAMP 与TWAMP light 主要区别在于Twamp 需要先使用TCP建立控制层面。

TWAMP

rfc5357

TWAMP light

rfc5357

TWAMP 配置

Cisco XR 的路由器目前只支持作为Server, 不支持作为Client, 也就是说它只能进行测量报文的反射, 而测量报文的主动发起方是Control-Client端。

Control-Client 端我们选择使用github 上的一个基于python的脚本twampy.

!!!!!  Router as TWAMP Resonder
ipsla
responder
  twamp
  !
server twamp
!
!

!!!!!  TWAMP controller 
[root@server1 twampy]#   ./twampy.py controller 172.18.87.49    
===============================================================================
Direction         Min         Max         Avg          Jitter     Loss
-------------------------------------------------------------------------------
  Outbound:           0us         0us         0us         0us      0.0%
  Inbound:        17.0min     17.0min     17.0min       148us      0.0%
  Roundtrip:     185.39ms    187.59ms    186.12ms       217us      0.0%
-------------------------------------------------------------------------------
                                                    Jitter Algorithm [RFC1889]
===============================================================================

如上图, 首先TCP建立控制层面,再由Control-Client发送UDP 探针,携带Tx timeslot; Router 收到后添加Revieve Timeslot, 反射探针.

TWAMP light 配置

!!!!! Router as TWAMP-Light Responder

ipsla
responder
  !
  twamp-light test-session 1
   local-ip 172.18.87.49 local-port 862 remote-ip 10.70.79.197 remote-port 777 vrf default
  !
!
server twamp
!
!

!!!!! TWAMP Light Controller

[root@server1 twampy]#   ./twampy.py sender 172.18.87.49:862 10.70.79.197:777
===============================================================================
Direction         Min         Max         Avg          Jitter     Loss
-------------------------------------------------------------------------------
  Outbound:           0us         0us         0us         0us      0.0%
  Inbound:        17.0min     17.0min     17.0min       136us     -2.0%
  Roundtrip:     173.09ms    180.26ms    174.47ms       344us     -2.0%
-------------------------------------------------------------------------------
                                                    Jitter Algorithm [RFC1889]
===============================================================================


!!!!!!!Command to check packet received   (version 7.1.3)

RP/0/RSP0/CPU0:ASR-9006-F#show ipsla twamp session 
Wed Nov  3 08:14:59.110 UTC
***** TWAMP Sessions *****
IP SLAs Responder TWAMP is: Enabled
Recvr Addr: 172.18.87.49
Recvr Port: 20001
Sender Addr: 10.70.79.197
Sender Port: 20000
Sender VRF Name: default
Session Id: 172.18.87.49:1635927288.140734154578682:0x394a9afa
Connection Id: 0xea
Mode: Unauthenticated
DSCP: 0
Pad Length: 0
Number of Packets Received: 91

***** TWAMP-LIGHT Sessions *****
Session status: Active
Recvr Addr: 172.18.87.49
Recvr Port: 862
Sender Addr: 10.70.79.197
Sender Port: 777
Sender VRF Name: default
Session ID: 1
Mode: Unauthenticated
Number of Packets Received: 500
Session timeout: 0

如上图,twamp light无control层面,只通过交互UDP探针;使用的端口号可以自己定义.

TWAMP和TWAMP light 相关抓包

TWAMP

Performance Measurement

SR PM 这个feature 支持采用TWAMP Light encoding的方式进行直连链路的延迟性检测, 参考文章Configure Performance Measurement

相关配置:

!!!!!!!!    Sender
 
RP/0/RP0/CPU0:P-2#show run performance-measurement 
Tue Mar  1 04:07:48.011 UTC
performance-measurement
interface TenGigE0/0/0/14
  next-hop ipv4 10.10.12.1
  delay-measurement
   advertise-delay 1000
  !
!
protocol twamp-light
  measurement delay
   unauthenticated
    querier-dst-port 11000
   !
  !
!
!
 
!!!!!!!   Reflector
 
RP/0/RP0/CPU0:ios#show run performance-measurement 
Tue Mar  1 03:59:25.056 UTC
performance-measurement
protocol twamp-light     <<<<  如果Sender使用默认端口862 , 则Reflector 只用配置"performance-measurement" 即可; 如果sender使用其他端口, 则reflector 需要配置一样的port,即额外添加以下配置
  measurement delay
   unauthenticated
    querier-dst-port 11000     
   !
  !
!
!

Sender:
 
RP/0/RP0/CPU0:P-2#show performance-measurement interfaces tenGigE 0/0/0/14 det$
Tue Mar  1 03:25:50.486 UTC
 
-------------------------------------------------------------------------------
0/0/CPU0
-------------------------------------------------------------------------------
Interface Name: TenGigE0/0/0/14 (ifh: 0x88)
  Delay-Measurement                 : Enabled
  Loss-Measurement                  : Disabled
  Configured IPv4 Address           : 10.10.12.2
  Configured IPv6 Address           : ::
  Link Local IPv6 Address           : ::
  Configured Next-hop Address       : 10.10.12.1
  Local MAC Address                 : 00bc.6062.2c38
  Next-hop MAC Address              : 00bc.6030.a838
  Primary VLAN Tag                  : None
  Secondary VLAN Tag                : None
  State                             : Up
 
  Delay Measurement session:
    Session ID          : 1
 
    Last advertisement:
      Advertised at: Feb 28 2022 16:31:45.428 (39245.136 seconds ago)
      Advertised reason: Advertise delay config
      Advertised delays (uSec): avg: 1000, min: 1000, max: 1000, variance: 0
 
    Next advertisement:
      Threshold check scheduled in 3 more probes (roughly every 120 seconds)
      No probes completed
      Rolling average (uSec): 1
 
    Current Probe:
      Started at: Mar 01 2022 03:25:33.122 (17.442 seconds ago)
      Packets Sent: 6, received: 6
      Measured delays (uSec): avg: 1, min: 1, max: 1, variance: 0
      Next probe scheduled at: Mar 01 2022 03:26:03.121 (in 12.557 seconds)
      Next burst packet will be sent in 0.557 seconds
      Burst packet sent every 3.0 seconds 
      Responder IP            : 10.10.12.1
      Number of Hops          : 1
      Probe samples:
        Packet Rx Timestamp       Measured Delay (nsec)
        Mar 01 2022 03:25:21.124            1530
        Mar 01 2022 03:25:24.124            1522
        Mar 01 2022 03:25:27.124            1528
        Mar 01 2022 03:25:30.124            1532
        Mar 01 2022 03:25:33.125            1528
        Mar 01 2022 03:25:36.125            1532

           

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