Ixia IEEE 1588 test plan

IXIA 测试1588

Ixia IEEE 1588 Test Plan

随着IEEE 1588作为一种网络时钟同步技术被随着越来越多的网络设备支持，实现对该技术的测试变得越来越紧迫。本文介绍Ixia如何实现对IEEE 1588的测试。

Ixia solution current Features

– IEEE 1588 version 2.2 in IPV4 (multicast) support – Two-step clocks support

– Mixed (non-PTP) traffic along with PTP traffic. Ixia ports will have the

ability to throttle transmit based on flow control packets being received. – 1 clock per port support

– Ports can be configured in Master or Slave mode manually.

– Histogram reporting Slave clock OFFSET from master is provided in

the form of plot along with PTP messages transmitted and received. – – – –

Aggregate statistics

Session/Per Interface stats

Per Interface configuration via protocol interfaces Negative testing

Programmable follow up messages in % of sync messages. See

how dropping 10-90% (sending 100% of sync messages) of follow-up messages affects the DUT

Sending follow-up messages with a bad packet

Purposely send data with timestamps that include jitter (Trying

to force sync failure)

– Ability to compose or decode PTP messages from IxExplore

– Support on LSM1000XMV/XMVR Family of 4, 8, 12 and 16 ports,

ASM1000XMV12X with EEPROM upgrade

– Minimum IXOS requirement: 5.30 EA

Future feature:

– – – – –

Multiple clocks per port Sync-E

Status per clock

Best Master algorithm support Peer Delay mechanism support

IXIA 测试1588

Suggest test topology:

1. 功能测试

Port 1 and port 2 are connected back to back

Port 11 and port 12 are connected to the two end of one network as following:

IXIA 测试1588

Step 2

对每个interface配置PTP属性

点击“PTP edit”目录栏的Edit按扭进行每个接口的PTP熟悉配置。

Master clock port:

如果选中，接口工作在 master模式；没有选中，接口工作在slave模式。

其中“message intervals”里面的3个值定义了PTP里面的Sync, Delay request, Annouce

IXIA 测试1588

报文周期发送时间, 前缀Log表示结果以幂来表示。因此3类报文缺省interval的时间都为1秒。

Announce receipt timeout:

announceInterval that must pass without receipt of an Announce message Number of

before the Announce Receipt Timeout event occurs

在slave 模式的接口上，建议修改为2。用缺省值0无法成功协商。

Step 3.

确认接口工作在正确的master/slave模式下面。

IXIA 测试1588

Clock offset/time slope/mean path delay 3个值给出了时钟的统计值。 这些参数的解释如下：

Anup Jethra：

From my understanding, each of 703s is boundary clock. If that is the case then first 703 will sync to Ixia Master clock. Second 703 will sync to first 703 and so on. Ixia slave port will sync to third 703. On Ixia slave port, mean path delay is the one between third 703 and Ixia slave. Clock offset is the overall clock offset between Ixia Master and Ixia Slave accounting for the entire PTP path.

If 703s were transparent clock, then Mean path delay would be the total path delay between Ixia master and Ixia slave - residence time between in each of 703s. In other words, mean path delay would be delay between Ixia Master and first 703 + delay between first 703 and 2nd 703 + delay between 2nd 703 and 3rd 703 + delay between 3rd 703 and Ixia slave. Clock offset would still be between Ixia Master and Ixia slave.

Time slope is between Ixia master and Ixia slave for both cases.

对于slave模式的接口，可以记录Clock offset/time slope/mean path delay 3个值变化的历史值。Clear -> start->save, 将记录结果存放到用户指定的excel文件。

IXIA 测试1588

PTPHistogram-2200000000000000_0.xl

该ASM1000XMV12卡的IxExplore

的配置保存如下。

ASM

XMV12_1588.zip

可以将XM机框链接AFD模块，将GPS时钟作为机框的时钟源。

这种情况下，Ixia master端口发出的PTP报文的timestamp就是GPS的timestamp。

2. Negative test:

修改master mode下的接口里面的Negative testing parameter参数，然后在PTP discovery information里面查看是否会对时钟有影响。 PTP discovery information里面的报文统计可以通过IxExplore里面的“clear statistics”清除。

IXIA 测试1588

3. 编辑PTP报文发送

除了在IxRouter里面可以创建PTP接口进行测试外，在IxExplore里面可以定义无状态的PTP格式的数据流进行功能测试。

To activate the PTP feature, begin at the Frame Data tab of the Stream Properties

Note: When a stream is configured as PTP, the Destination Address on the Streams properties DA/SA tab will be deactivated and grayed out, due to the fact that Ethernet, IPv4 and UDP transmission of PTP packets relies on a reserved Destination Address.

2. Choose Ethernet II, IPv4, and PTP/UDP/IP. (A Warning message will occur, regarding frame size.)

3. Change the Frame Size to 128 (so that it is long enough to accommodate the PTP header). 4. Click Edit.

RTP statistics:

PTP port-level statistics can be collected by checking in the Statistics tab

IXIA 测试1588

IXIA 测试1588

Appendix A- Protocol interface help message

Area

Characteristics

Field

Domain Number

Description

The domain is identified by an integer in the range of 0 to 255.

Priority 1

A user configurable designation that a clock belongs to an ordered set of clocks from which a master is selected. A user configurable designation that provides finer grained ordering among otherwise equivalent clocks. A specific PTP port on a PTP node

Defines the clock offset in nanoseconds. Master sends PTP messages with Start Offset added to the clock. Identifies a clock

Priority 2 Port Number Start Offset(s) Clock Identity

Number of announceIntervalthat must pass without receipt of

Announce Receipt

an Announce message before the Announce Receipt Timeout event

Timeout

occurs Delay Mechanism Either (1) "end-to-end" or (254) "disabled"

Defines a clock's TAI traceability.

The clockClass attribute of an ordinary or boundary clock denotes the traceability of the time or frequency distributed by the grandmaster clock.

Defines the accuracy of a clock. See Table 10-3.

Clock Class

Clock Accuracy

Master Clock Port If checked, configures the port in master mode.

Message

IntervaLog Sync ls

The mean time interval between successive Sync messages

The minimum permitted mean time interval between successive

Log Delay Request Delay_Req messages, sent by a slave to a specific port on the

master. Log Announce Bad CRC %

Mean time interval between successive Announce messages Percent of follow-up messages sent with bad CRC

Negativ

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e

Testing

Timestamp Errors

The time error between a slave and a master ordinary or boundary clock

Bad Timestamp % Percent of follow-up messages sent with bad timestamp

Defines how many delay response messages to be dropped. Drop delay response messages expressed as percentage of received delay request messges. Normally, delay response is sent by the master corresponding to each delay request massage received. For negative testing, user can configure Ixia port to drop the delay response message to see how the DUT behaves.

Defines how many follow-up messages to be dropped. Drop follow-up messages expressed as percent of sync messages. Normally, a follow-up message is sent out corresponding to each sync message. For negative testing, user can configure Ixia port to drop the follow-up message to see how the DUT

Delay Response Dropped %

Follow-up Dropped %

Table 10-3

IXIA 测试1588

Appendix B. PTP Discovered Information

Table 10-12. PTP Discovered Information Tab

Field/Control

Interface Description

Description

The Interface Description for the Ixia protocol interface that is

negotiating with the PTP Server.

IXIA 测试1588

Clock ID State Time Stamp Announce Messages Sent

Announce Messages Received

Sync Messages Sent Sync Messages Received

Follow-up Messages Sent

Follow-up Messages Received Delay Request Messages Sent Delay Request

Messages Received Delay Response Messages Sent Delay Response Messages Received

Identifies a clock.

Defines the state of the clock:

master or slave, unknown or uncalibrated Timestamp of statistics.

Number of announce messages sent by the interface.

Number of announce messages received by the interface. Number of sync messages sent by the interface. Number of sync messages received by the interface.

Number of follow-up messages sent by the interface.

Number of follow-up messages received by the interface.

Number of delay request messages sent by the interface.

Number of delay request messages received by the interface.

Number of delay response messages sent by the interface.

Number of delay response messages received by the interface. The offset of the slave clock in nanoseconds with reference to its master, as calculated by the slave per 1588 protocol. It is a measure of time transfer.

The ratio of the slave clock frequency to its master clock frequency. It is a measure of frequency transfer.

The mean propagation time between master and slave clock as computed by the slave.

Click Start to start (or resume) recording. Click Stop to stop recording. Clicking Stop does not clear the accumulated data.

Clock Offset

Time Slope

Mean Path Delay

Record Histogram Data

Clear Histogram Data Click Clear to clear the accumulated data.

IXIA 测试1588

Click Save to save all accumulated data. A typical Save As dialog

Save Histogram Data to will appear. Disk NOTE: To avoid overwriting previously saved data, modify the

suggested filename. Saved PTP Discovered Info Data

When PTP histogram data is saved to disk, a comma-separated-values (.csv) file is created. The .csv file can be opened as-is, or can be opened in MS Excel, as shown in the following example (Figure 10-19).

The columns in the spreadsheet contain the types of information described in Table 10-13.

Table 10-13. PTP Discovered Information Saved Data

Column A B C D E F G H I

Description

Chassis name Card number Port number PTP Clock ID PTP Port Identity PTP Time Stamp

PTP Clock Offset from master Time Slope Mean Path Delay

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