Welcome Message

Hello my dear reader,

Welcome to my blog, which is dedicated to Cisco technologies. On its pages we will talk about the limitless world of telephony and networking.

We will focus mostly on Cisco collaboration solutions and technologies. These are IP PBX based on Cisco Unified Communications Manager and Cisco Unified Communications Manager Express, Cisco contact centers, Cisco Voice Gateways, etc. Also, I will introduce you the education news: Cisco authorized courses, my own developed training programs, our upcoming events, online learning.

If you have any questions regarding my posts, job or activities, please feel free to ask your questions. I will try to answer them when I have time.

If you are satisfied with the content of my blog, isn’t that worth a beer or coffee? Donations help me to continue supporting the blog and creating new posts here — things for which I spend hours of my free time! Thank you very much!

Sincerely, Dmytro Benda

Monday, December 17, 2012

A command to synchronize the E1 link on Huawei voice gateways

Good afternoon,

A few days ago, one of the readers of my blog, Alexander Bakulin, asked me what command is used to synchronize E1 links on Huawei voice gateways. I could not answer this question, because I do not work with the Chinese devices, and advised Alexander to google. He found the answer to it and, in fact, forwarded the answer to me.

Since the issue of E1 synchronization for Huawei may be of interest to many more engineers working with Huawei, I decided to post Alexander's answer. I quote him:

"Maybe it will be useful for someone - the command on the Huawei AR2220 voice gateway to synchronize the E1 link is as follows:
clock source 1 4/0/0 priority 1where 4/0/0 is the installation location of the module with E1 interfaces. At least the "slips" have stopped accumulating ..."

Very similar to Cisco :) - the Chinese know their stuff :)

Thank you Alexander for sharing your experience.

You can read about synchronization of E1 links on Cisco gateways here

Monday, December 10, 2012

Unsuccessful call to the PSTN via the Cisco 5400 (H323) gateway due to incoming dial-peer 0

Good afternoon,

Today I happened to be convinced once again in practice how it is important to understand the principles of call routing in Cisco voice gateways. One of my students had the following problem: he was performing a new installation of CUCM at a customer side and then connecting the CUCM to the PSTM via the Cisco 5400 voice gateway. To begin with, he decided to test the connection to PSTN, and, therefore, call routing on the CUCM was configured. On the gateway, the minimal dial-peer configuration was performed.

However, when trying to call the PSTN, the connection was not established. Debug isdn q931 was started on the gateway to determine the reason for the call release.

Saturday, December 8, 2012

Cause 127 Cisco VGW - Huawei VGW (H323)

Hello,

Last week, I helped two followers of my blog to solve a problem with an H323 connection between a Cisco Voice Gateway and a Huawei Voice Gateway. The topologies of both networks were as follows:

PBX1 (E1) -> E1 Cisco -> H323 -> Huawei E1 -> (E1) PBX2

The problem was this one: when an outgoing call was made from PBX1 to PBX2, the connection was not established, the caller received a hang-up. With a more detailed diagnosis, it was found that the Huawei gateway released the call.

Debug cch323 h225 was launched on the Cisco gateway to clarify the reason for the hang-up. He showed that Huawei was disconnecting the call with Cause 127: