Month: June 2012

Protecting a VoIP Network with Security Appliances

VoIP and IP telephonyWe can protect our voice network with simple Auxiliary VLAN but sometimes to be more secure Auxiliary VLAN are not enough. In this case we can use Security appliances such firewalls or VPN termination devices or both.

Firewall maybe seems like very clean and simple mechanism to protect RTP protocols transmitted voice packets but there’s a problem. Protecting voice networks with a firewall is not so simple because we are not sure what UDP port will be used by the RTP voice packets flow.

If we look at some Cisco network architecture and Cisco device environment, a UDP port for an RTP stream is an random port selected from the pool of 16,384 to 32,767. We surely don’t want to open all those ports on firewall just to be sure that the VoIP will function well. So many open ports may be seen from other side like a bunch of security holes.

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Implement Auxiliary VLANs to make VoIP Networks secure

Ways to ensure the voice network security are many. In this article we will se the first of them that must be configured in every serious network. Implementing Auxiliary VLANs will make VoIP Networks more secure using separated VLANS for data traffic and voice.

VoIP axiliarity VLANVoice and data traffic will be transferred in the same way across the same cable and same switch by default. That means that calls and all other network traffic will be transferred in the same time in the same way and every user on the network will be able to see that data using some network sniffing tool like Wireshark. This default network setting may be used to capture call packets that are crossing the network and attacker can reproduce the call in .mp3 or some other sound format. We need to separate voice network from data network completely in order to make impossible to sniff call packets from user computer. 

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Make voice Network more secure

VoIP SecurityWe mentioned earlier all different attacks that can be focused to our VoIP network. Now is the time to see how we can apply different protection methods to avoid VoIP quality mitigation that can be started by all those attacks.

Separating voice traffic from data traffic with voice VLANs or by use of VPNs and firewall to protect voice traffic can easily prevent basically all most common attacks. One more thing that is important and often ignored is the security of voice endpoints and servers that can be increased with some simple configuration changes.

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Cisco EnergyWise – New way to save energy

With Cisco EnergyWise Technology you can effortlessly direct the energy consumption of every network connected IT device in your company.

EnergyWiseCisco EnergyWise is certified as the winner of the Best of Interop Green award. It is a very important part of the Cisco Borderless Network Architecture. Quite significantly, this kind of equipment is extremely efficient in the management of campus IT energy, enterprise-level monitoring as well as reductions of extensive energy.





Energy reduction is efficient and convenient. With the assistance of your Cisco network as the core of your energy intelligence, there are many possibilities such as:

  1. Oversee the energy necessities of new and current Power over Ethernet (PoE) devices.
  2. Increase the limit of power management to PC’s, desktops and laptops.
  3. You can also append “power save plus mode” to IP phones in order to increase power savings where it is possible.
  4. Enlarge your control to high-power devices like virtual compact switches and desktops.
  5.  Through the interactive GUI’s you can control all energy conservation efforts.

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Voice protocols – VoIP protocols

VoIP protocols functionalityThis article will list all well known and famous “voice protocols”. And, also we will shed some light on various things that those protocols are doing that make up a voice over IP network functional.

VoIP Protocols

VoIP networks are very popular these days. In order to support communication between traditional PBXs, Cisco IP phones, analog PSTN, and the analog telephones, all over IP network, quite a number of protocols are needed. Few protocols are indicating protocols (for instance, MGCP, H.323, SIP, H.248, and SCCP) used to position, sustain, and bring down a call. Other protocols are marked at the real voice packets (for example, SRTP, RTCP, and RTP) relatively indicating information. Few of the most common VoIP protocols are shown and described here.

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