Archive | April, 2011

Restart a Cisco Unified Communications Manager(CUCM)

The proper way to reboot or shutdown a Cisco Unified Communications Manager (Callmanager) server is to issue the “UTILS SYSTEM RESTART” command from the console. Alternatively you can SSH to the server and issue the restart command remotely. You can SSH to your server using any SSH client you wish. Putty is a free, commonly used SSH client. I personally use SecureCRT, however, you must purchase a license. (There is a trial version available as well.)
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Posted in Cisco, Juniper, Microsoft, Net Security, VOIP, VOIP Hardware2 Comments

step by step follow the changes in the Routing table

During the TSHOOT course of my studies.
I got to know one of features that the Cisco added to the operating system 12.0 after it was one of the things hidden in the command prompt in version 11.0

this command is
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Posted in Cisco, Juniper, Microsoft, Net Security, VOIP, VOIP Hardware2 Comments

IPV4 VS IPV6

Drew my attention yesterday and during the search in Google that there is no subject to compared between IPv4 IPv6 So let me be the first one to offer this service to our brothers that the issue is important and somewhat complex for some.

Before I start I liked to say that this is not compared to the literal sense, because most of us are well aware the IPv4 features
but I will to clarify the advantages of IPv6, but in the form of comparison with the IPv4.

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Posted in Cisco, Juniper, Microsoft, Net Security, VOIP, VOIP Hardware4 Comments

SIP domain vs DNS domain

If you deal with SIP products (such as CUPS/CUPC), you’ll have to deal with SIP domain sooner or later.

Here are some of the most asked questions:
1) What is a SIP domain?
2) Does the SIP domain has to match the DNS domain?
3) What if I’m not using DNS with the application?

SIP domain is more like on application layer versus DNS domain on network layer.

Let’s take a look at a real life example. Let say, you have a SIP application that can send instant message and make phone calls (such as CUPC and MOC).

When the application initiate a call, the SIP message would look like this “INVITE 6002@acme.com“. This message means – “I want to call extension number 6002 in ACME company”.

Usually, the first stop of this SIP message would be your local proxy server (SIP proxy). The local proxy server will determine how to route this message to its destination.

Whenever a SIP proxy server receive a SIP message, it will always look at the domain part of the SIP request. Based on the domain, SIP proxy will determine how to route the message.

Here’s the detailed workflow:

1) If the SIP message’s domain matches with the SIP domain configured on SIP proxy, SIP proxy will handle that within the same domain. Otherwise, SIP proxy will forward it to a different domain (or just ignore/discard it depends on the design).

This is very important. Let say, CUPC sent a message “INVITE johndoe@acme.com” to SIP proxy. However, the SIP domain configured on SIP proxy was “abc.com”. The SIP proxy will treat it as “foreign message” and try to forward it to its destination domain or discard/ignore it.

2) SIP proxy will look at the SIP static routes to determine the messages’ destination.

SIP static routes are configured on the SIP proxy server on application layer. Don’t confuse it with TCP/IP static routes.

On CUPS 6.x, you may configure static routes on CUPS Admin > Cisco Unified Presence > Proxy Server > Static Routes. On OCS 2007, you may configure static routes by right-click on the “Front End” folder > properties > routing.

You may configure IP address or FQHN for static routes.

For example:

Static route: acme.com —> apple.acme.com
This means for all SIP messages with SIP domain acme.com will be routed to a host with FQHN apple.acme.com.

Static route: acme.com —> 192.168.1.100
This means for all SIP messages with SIP domain acme.com will be routed to a host with IP address 192.168.1.100.

Keep in mind, the above is on application layer.

3) If there’s no static route configured, SIP Proxy would try to determine the next hop by name resolution.

If SRV records were configured, SIP proxy would try to resolve the domain by SRV records.

Then SIP proxy would try to resolve by A records.

Now lets answer the questions.

Q1: What is a SIP domain?
Answer: A SIP domain is an application layer configuration that define the management domain of a SIP proxy.

2) Does the SIP domain has to match the DNS domain?
Answer: Yes, it has to match the DNS domain in most of the scenarios. And it’s strongly recommended to match the SIP domain with DNS domain.

3) What if I’m not using DNS with the application?
Answer: You may or may not be able to use application features if you don’t have appropriate name resolution configured. For example, in CUPC 1.2.x, you may use presence feature without name resolution to the presence FQHN. On CUPC 7.0.x, it doesn’t work (because they changed the design on 7.0.x). If you don’t have a DNS, you may use local host files to do name resolution.

Posted in Cisco, Juniper, Microsoft, Net Security, VOIP, VOIP Hardware17 Comments

MDI or MDI-X than Auto-MDIX technology

Auto-MDIX is a technology developed by HP by Dan Dove and Bruce Melvin  this technique allow us to use any cable kind Straight-Through or Cross Over in Swish, regardless of the binding with hop or router or a PC because the port will choose automatic which cable is   that suits him.

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Posted in Cisco, Juniper, Microsoft, Net Security, VOIP, VOIP Hardware7 Comments

Virtual link and OSPF Areas

One of the things that I think it must be stuck in the mind of everyone who works in the field of networks is how to setup the Virtual Link in the OSPF and the consideration of the fact that the subject is very important album will present it to keep the subject as a reference to any one of us

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Posted in Cisco, Juniper, Microsoft, Net Security, VOIP, VOIP Hardware7 Comments

Basic facts about Cisco IOS Image 15.0

On the occasion of the announcement of my first blog on the Internet and by extension the subject of the former that you throw it the last time about how to understand all versions of Cisco IOS and what contains
During the preparatory of the subject caught my attention the subject of the new generation to Release the Special Image IOS 15 and considering that Cisco did not authorize anything about the new version and the ingredients included New services, but it said one thing and dangerous, which I will talk with you on this TIPPS in the form of facts.

 

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Posted in Cisco, Juniper, Microsoft, Net Security, VOIP, VOIP Hardware4 Comments

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