Firmware Upgrade for Cisco IP Phones (CUCM)

Good morning!

I wanted to write this post long ago, however I was extremely busy and did not get around to take the required screenshots. And when preparing for the next course, I had to upgrade the firmware on our lab phones. So it became possible to write about what needs to be done on CUCM to update / change firmware. The procedure is quite simple.

CUCM 9.0 - How to install licenses

Hello!

Today we'll talk about how licenses for CUCM 9.0 are installed. Since the process in the new version differs significantly from earlier predecessors, I will give the entire installation procedure with screenshots taken from our lab CUCM.

CUCM 9.0 - Pause when dialing a number with the Speed Dials keys.

Good morning!

The festive New Year's fireworks have died down, and working days are coming again. :) I decided to start 2013 with a small article devoted to the problem of inserting a pause in extension dialing when calling from CUCM to, for example, your PSTN.

Quite often, on various forums, the question was discussed - how to implement automatic extension dialing on CUCM? Suppose a CUCM user calls a company where not all employees have direct incoming DID numbers. Instead, the call arrives at the company's general number, and then the auto-attendant or DISA function is triggered and prompts you to dial the employee's extension in DTMF mode. In manual dialing, this can be done without problems, but what about the speed dial buttons on Cisco IP phones? How to pause for them while playing the auto-attendant greeting or, in the simplest case, while establishing a connection with the called PBX?

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 1, where 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

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.

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:

Virtual Machine Settings for Cisco UC Products

Hello,

Since more and more virtualization is being used in real projects, my students are increasingly asking me questions like: "What should be the parameters of virtual machines to install CUCM, CUC, UCCX?"

The answer to this question is given by the vendor itself:

https://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/uc_system/virtualization/cisco-collaboration-virtualization.html

Here you can also find templates for virtual machines (ova files).

Have a good day! :)

Examples of the simplest CUCME configuration for beginners

Good morning!

For those who are taking their first steps in the world of VoIP and learning how to configure Call Manager Express (CUCME), I think the following link will be helpful. The document provides examples of the simplest configuration of SCCP and SIP phones for registration on CME:

http://www.i-1.nl/blog/wp-content/uploads/CUCME-cheatsheet-1.0.pdf

As you can see, everything is very simple :)

About troubleshooting poor voice quality issue when calling from Cisco Jabber clients

Good morning!

A couple of weeks ago, I was troubleshooting a problem with poor voice quality when calling from Cisco Jabber software clients. The customer's VoIP network covered several offices in different cities, CUCM 8.6 and СUP 8.6 were used. In general, there were about 1,500 users in their enterprise telephone network, and more than a thousand of them did not have Cisco hardware phones and called each other using Cisco Jabber.

The problem was that when calling from Cisco Jabber, users complained about poor voice quality, namely, interruption of speech, gaps, etc, while words and phrases were sometimes completely unintelligible. Moreover, the problem was present even when making calls within the LAN! Usually, this phenomenon is associated with network problems - a large percentage of voice packet losses. And the reason for the loss of voice packets could be a high jitter value, incorrectly configured queues on routers, insufficient bandwidth, enabled VAD, and the wrong choice of codec.

Configuring a Cisco Router to Connect to an ISP Through an ADSL Modem

Hello!

Not so long ago, I helped my friend to configure a Cisco router in their office to connect to their Internet Service Provider (ISP) via ADSL. They had a UC520 SMB router installed, which needed to be connected to the ISP via an ADSL modem. A diagram of that connection is shown in the figure above.