Cisco Systems 2600, 3600 Technical Details of the Cisco Hoot and Holler over IP Solution

Cisco Hoot and Holler over IP Feature Overview

Cisco IOS Release 12.1(5)T

Technical Details of the Cisco Hoot and Holler over IP Solution

This section describes how Cisco Hoot and Holler over IP works from a technical perspective. It covers

design considerations in terms of IOS configurations and DSP mixing functionality as well as

bandwidth planning and QoS, with the following assumptions:

1. That you have some level of Cisco IOS experience.

2. That you have some experience configuring QoS features with Cisco IOS. If not, please refer to the

IOS documentation on CCO at:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/ip_c/index.htm

3. That you have some experience configuring VoIP with Cisco IOS. If not, please refer to the IOS

documentation on CCO at:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/multi_c/mcprt1/mcdv

oip.htm

4. That you have some experience configuring IP multicasting with CiscoIOS. If not, please refer to

the documentation on CCO at:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/ip_c/ipcprt3/1cdmulti.

htm

5. That you have a working IP network, with IP multicasting configured using the Cisco2600 and

Cisco 3600 series routers. If not, please refer to the documentation on CCO at:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/index.htm

http://www.cisco.com/univercd/cc/td/doc/product/access/acs_mod/cis2600/index.htm

http://www.cisco.com/univercd/cc/td/doc/product/access/acs_mod/cis3600/index.htm

6. That you are familiar with Cisco IP/TV. If not, please refer to the documentation on CCO at:

http://www.cisco.com/univercd/cc/td/doc/product/software/iptv30/

7. That you understand basic hoot and holler concepts and equipment.

When deploying Cisco Hoot and Holler over IP, first consider how the voice streams are going to be

mixing and distributed to other locations. This is done using a combination of two technologies:

•IP multicast (IPmc)

•DSP arbitration and mixing

Since hoot and holler is generally used to allow many people to simultaneously talk and listen to other

people within a hoot group, by definition it requires that the same speech be delivered to multiple parties

at the same time. In an IP network, this functionality uses IP multicasting (IPmc). IPmc allows a source

to send a single packet into the IP network and have it duplicated and sent to many listeners b y the other

routers within the network. This technique is beneficial in that it does not require the source to know

how many listeners there are, as well as not requiring additional processing burden on the source by

having to send a copy of each packet to all listeners. IPmc also allows for listeners to dynamically join

IPmc groups, which eliminates the administrative burden of adding new users every time a new IPmc

session is initiated.

Now that we have established that an IP network can forward packets in a way similar to existing hoot

and holler networks, we also must examine how the individual router/gateways can handle mixing and

arbitrating the various voice streams that could initiate or terminate on its voice ports. This functionality