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NE40E can use the 1588ACR to perform clock synchronization

Publication Date:  2014-11-06 Views:  125 Downloads:  0

Issue Description


Router A (GE port) —— (GE port) B (IP-Trunk) —— (IP-Trunk)  Router C(IP-Trunk) —— (IP-Trunk) Router D(IP-Trunk) —— (IP-Trunk) RouterE

Versions: all the routers are V600R003C00SPCa00

Fault phenomenon:

Router A is 1588 ACRserver. Router B, Router C, RouterD, RouterE are 1588 ACR client. At present, only B successfully synchronized, Router A, Router C, and RouterE synchronization failed.

Every of the IP - Trunk interface contain 2 Pos interfaces.

Handling Process

1, check the configuration of the equipment and no fault was found

2, All the routers synched failed have two member interfaces connecting with the server.


There are two kinds of 1588ACR client as distributed client and centralized client. And the distributed client has some limits as  following:

(1) the distributed client can't deal with the packets come in from different interfaces although the packets come from the same server .

(2) the distributed client can't deal with the packets come from different server although the packets come in from the same interface.

(3) the distributed client can't recognize the ACR packets with mpls labels

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All NE40E and CX600 can only support distributed client before V600R005C00 version.


3, The device synched failed Router C, RouterD, RouterE  are all V600R003C00SPCa00 , and they are distributed clients. They connect with the server via IP-trunk interface which has two member interfaces. Because the distributed client can't deal with the 1588ACR packets come in from different interfaces and the same server. The UDP ports of 1588ACR packets are  319 and 320, so the hash result will be different and the packets with different UDP port will forwarding by different member interfaces of the IP-trunk. The distributed client can only open one interface for 1588ACR. The synchronization wil be failed  when the 1588ACR packets come in from the interface without the 1588ACR function .


Root Cause

Live network equipment for 1588ACR is distributed client, and connect with the clock server via IP-trunk of two member interfaces.  1588 ACR deploy restrictions in NE40E is that the distributed client can't deal with the 1588ACR packets from the same server and different ports. The UDP port for 1588ACR may be 319 or 320, so the 1588ACR packets may be hash to different path of the member interfaces for the IP-trunk.And distributed client can only open one port for 1588 function. So one of the member interface does not have the 1588 function. So the synchronization wil be failed  when the 1588ACR packets come in from the interface without the 1588ACR function .


1, modify the configuration using single POS interface or IP-trunk interface configure only one member interface , to make the 1588ACR packets coming from the same interface .

2, upgrade version to V6R6 or later, and configure ptp-adaptive trunk enable on the 1588ACR server . This command can adjust the port number of 1588 packets into 320 to avoid the different hash result. The destination port of 1588 packets should be 319 and 320. After change the related 1588 messages will not match the protocol standard, so please specify the using risk.