EHX Error message:TIME OUT-BACH respones is slow

EHX V12.0 :

you will meet the error message: time out-BACH responses is slow for the third party AES67/ST2110 steam processing.


Here are some rules we know that will cause this error in SDP file of RX steam:

  1. some SDP of streams use the same session ID at the original line; o = (owner/creator and session identifier)

  2. SDP doesn’t use a=ptime of 1 (1ms) or 0.125 (125us)


The o= field contains information about the originator of the session and session identifiers. This field is used to uniquely identify the session.

  • The field contains −

  • o=<username><session-id><version><network-type><address-type>

  • The username parameter contains the originator’s login or host.

  • The session-id parameter is a Network Time Protocol (NTP) timestamp or a random number used to ensure uniqueness.

  • The version is a numeric field that is increased for each change to the session, also recommended to be a NTP timestamp.

  • The network-type is always IN for the Internet. The address-type parameter is either IP4 or IP6 for IPv4 or IPv6 address either in dotted decimal form or a fully qualified hostname.

Sometimes we manually modify some SDP, the session ID is not set to a different value. the EHX editor has no warning, but the EHX log will show timeout- BACH responses is slow. there will be no RX streams are decoded.


Packet time

From RFC4566

  a=ptime:<packet time>


         This gives the length of time in milliseconds represented by

         the media in a packet.  This is probably only meaningful for

         audio data, but may be used with other media types if it makes

         sense.  It should not be necessary to know ptime to decode RTP

         or vat audio, and it is intended as a recommendation for the

         encoding/packetisation of audio.  It is a media-level

         attribute, and it is not dependent on charset.


For CC we only use ptime of 1 (1ms) or 0.125 (125us)



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