AI, ML, Development + Cisco Learning Blog Learning about Machine Learning, Artificial Intelligence, related devlopment topics and formerly Routing and Switching, Datacenter, Security and other topics, CCIE #23664, Frank Wagner

30. August 2007

Done 642-642 QoS today

Filed under: QoS,Voip — ocsic @ 21:28

As my last project would haven’nt been about qos, i would have not been that good and it would have not been that easy. I’m on my way to the CCVP cert. Currently i just hope i can learn things as quickly as possible. This test has not been that difficult. QoS is a topic that has not changed a lot in the last years. Even cisco’s design guide for campus qos is about 2 years old from 2005. So things you will learn are about standards, that have not changed a lot since.

What i haven’t seen is an RSVP or IntServ implementation. I would like to test it a bit with dynamips, but i have to keep an going.

Just know now how to implement LLQ, CBWFQ, PQ, CQ and WRED for example. Knowing about COS and DSCP values. I have not had anything about thresholds in the test. I had 45 questions and the passing score was 790 points. Thanks to the good vue testcenter. I had quite a lot of problems with prometric. Probably this is the reason why cisco changed to use only vue as a testing center for cisco tests. Everythings was working fine. I did the test at OpenLine, Maastricht in the Netherlands.

25. August 2007

QoS campus design / telephony / avaya / diffserv

Filed under: QoS,Voip — ocsic @ 12:52

I have implemented a QoS design for a customer with about 5000 nodes per campus. The design is relatively straigt through. Once you have decided with classes you want to implement, you have to configure the different devices. There has been an access, distribution and core layer. It’s the best to mark as close to the apllications as possible. So at the access layer we had 3750, 4000/4500. The 3750 supports srr and for the 4000 it’s dependend on the module. But for the 4000/45000 you don’t have input queues. As forexample the 6500 it depends all also on the module. You have to find out what kind of hardware queues there are. It’s probable a notation like 1P3Q8T, what means something like, 1 priority queue, 3 normal queues and 8 thresholds per queue. Sometime you can find also the notation 4Q8T/1P3Q8T, that means the one priority queue is able to be a normal or a prio queue.

If you have measurements about the actual network traffic, you can distribute the traffic on the different queues and thresholds. If not, it’s maybe good enough to have a priority queue and to roughly estimate the other queues, but maybe not go to deep into changing the default thresholds. Later it might be necessary. If you don’t have enough queues left and you want to keep up you queuing schema.

There is a good design guide for enterprise campus QoS implementation and i suggest taking this as a good starting point in you QoS campus design. It coves all the different catalyst types and also gives some suggestions about the ECN/DBL (dynamic buffer limiting) marking espacially for the 4000/4500’er catalyst.

This could be a good feature when both stations (server/client) support the ECN flag. I read about the xp/vista does it not have enabled by default. But it’s only available at the 4000/4500’er.

Make sure you use hardware queueing and not queuing in software. This will save you from having problems with cpu overload. As long queueing is done in hardware, you will be on the safe side.

Avaya does not have recomandations about qos implementations on cisco hardware. Phones can be configures like setting voice bearer traffic to COS 5 and Signaling traffic to COS 3. You can overwrite the data port with the PC connected to COS 0. This would be a relativ straight forwarded setup.

QoS is a quite complex task. It’s necessary to develop and administrate the current needs constantly.


23. August 2007

642-642 QoS

Filed under: QoS,Voip — ocsic @ 12:25

Currently going for the first QoS test for the CCVP. Think this is the most difficult one. I like to take the hard part first. I haven’t seen any RSVP implementations. I wonder if it’s really widely used outside in the network for QoS. I will write some comments to my QoS implementation for a customer with about 5000 access ports per site in the next days.

QoS can be quite a complex task. It seems simple, but implementing it continuously on differnt kinds of hardware queues and different queueing techniques, could be quite callenging.

6. August 2007

CCVP / Job

Filed under: Allgemein,Voip — ocsic @ 11:14

I’m currently starting the ccvp path first. I think this is a better idea in terms making your value sure. I don’t know if i will reach ccie for routing and switching. But i can do ccvp in time. So this will be my next goal first.

I had a very bad experiance with head hunters and a company. Seems like they are only out there to make the profil and after half a year they kick you out again. Well i should have known this. I’m currently looking for a new job. So if anyone has something to offer, i would be glad to hear about.

28. Mai 2007

Password recovery for the CCM 5.0

Filed under: Voip — ocsic @ 11:29

If you don’t have access to the ccm anymore, cisco provides a neat way to reset the password.

Just login with pwrecovery on the console and password is pwreset.

Then you can reset the admin and secure password.

Here is the corresponding link:

26. Mai 2007

CallManager Express and Dynamips

Filed under: dynamips,Voip — ocsic @ 22:17

As you know maybe, CallManager Express is able to manage small sites with up to 100 phones. I installed a CME capable IOS on a dynamips 3660 router and i’m able to connect a real phone to the dynamips router.

Here i explained who you could make your local device and network available to your dynamips routers. Keep in mind that you have to allow traffic on your newly created interfaces, for example br0 and allow the new traffic, if you have a firewall enabled.

For using tap0 and br0 look at this link:

You need an image that is callmanager express capable IOS. Look at and IOS Feature Navigator and search for CallManager Express. You need a valid CCO account for downloading IOS images.

Currently dynamips is able to simulate a lot of 3600’er and 3700’er routers. So choose the one that matches your needs.The 3660 only support CME 3.0 though.

You have to add then some extra flash to keep up the files for the phones.

Dynamips supports the disk option. So „disk0 = 256“ gives you a lot of space for files.

You have to format the flash before using it.Do thi dependend on the router IOS with „erase flash:““ or „format flash:“

On the 3725:

cme#erase flash:
Erasing the flash filesystem will remove all files! Continue? [confirm]
Erasing device… eeeeeeeeeeeeeeeeeeeeeeeeeeeeee …erased
Erase of flash: complete

Then you can tftp files to flash, for example moh file „“

cme#copy tftp flash
Address or name of remote host []?
Source filename []?
Destination filename []?
Accessing tftp://…
Erase flash: before copying? [confirm]n
Loading from (via FastEthernet2/0): !OOO!OO
[OK – 496521 bytes]

Verifying checksum… OK (0x206E)
496521 bytes copied in 15.516 secs (32001 bytes/sec)

Directory of flash:/

1 -rw- 757 <no date> startup-config
2 -rw- 496521 <no date>

268435452 bytes total (267938040 bytes free)

To setup moh (music on hold) do the following:

ip source-address port 2000


And configure, as it’s not the default, „multicast-moh“ under each ephone you want the feature.

You should hear now the moh sound.

You should also copy the cme-gui archive to the flash:

cme#archive tar /xtract tftp:// flash:/

Login to your router through:

26. März 2007

IP Communicator and ccm 4.1.3

Filed under: Voip — ocsic @ 20:52

I should go more for preparing the lab exam again, but currently i’m playing around with callmanager and ip communicator from cisco. IP communicator is a softphone and can be installed on windows os. You then can emualte two cisco phones and do some testing.
Here are two screenshoots of this.


IP Communicator

15. März 2007

Installing CallManager 4.1.3 on free VMWare Server Edition

Filed under: Voip — ocsic @ 23:44

Using a fresh Windows 2000 Server installation and CallManager 4.1.3.

After installing Windows Server 2000 on VMware, i took a 15 GB disk and a single processor system.

I had the problem with a windows 2000 server cd and an already applied sp4 without msjava. I had to install java first. It’s available as a file called: MSjavX86.exe.

This is the complete version of ms java.

For the windows 2000 server installation add also the snmp service and IIS.
Importing these registry settings.


Windows Registry Editor Version 5.00


[HKEY_LOCAL_MACHINE\SOFTWARE\Spirian\System Info\OS Service Release]


Afterwards install the latest OS patches and upgrades:


The system will boot three times.

After that you will have to import these registry setting again:




Then copy the file shutdown.exe to the following directory:

copy c:\program\cisco\updates\2000 2.7sr8\shutdown.exe to C:\Utils

Then start the callmanager installation by starting ccmsetup.exe

Install CallManager 4.1(3) by inserting the CD and opening the ccmsetup.exe

After Callmanager Reboots check to see if the WorldWideWeb Publishing Service is set to manual and stopped. Set it to automatic and start it.

For installing ccm i had to temporary set the memory to 1024 MB for the virtual machine.

CCM Installation Success


Another Method using the image CD’s

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