Cisco Systems 78-11741-02 Wireless Office Headset User Manual


 
IPC-493
Cisco IOS IP Configuration Guide
Configuring PGM Host and Router Assist
Note Support for the PGM Host feature has been removed. Use of this feature is not recommended.
This chapter describes the PGM Host and Router Assist feature. PGM Host and Router Assist enables
Cisco routers to support multicast applications that operate at the PGM transport layer and the PGM
network layer, respectively.
The PGM Reliable Transport Protocol itself is implemented on the hosts of the customer. For
information on PGM Reliable Transport Protocol, refer to the Internet Engineering Task Force (IETF)
protocol specification draft named PGM Reliable Transport Protocol Specification.
For a complete description of the PGM Host and Router Assist commands in this chapter, refer to the
“PGM Host and Router Assist Commands” chapter of the Cisco IOS IP Command Reference, Volume 3
of 3: Multicast. To locate documentation of other commands that appear in this chapter, use the
command reference master index, or search online.
To identify the hardware platform or software image information associated with a feature, use the
Feature Navigator on Cisco.com to search for information about the feature or refer to the software
release notes for a specific release. For more information, see the “Identifying Supported Platforms”
section in the “Using Cisco IOS Software” chapter.
PGM Overview
Pragmatic General Multicast (PGM) is a reliable multicast transport protocol for multicast applications
that require reliable, ordered, duplicate-free multicast data delivery from multiple sources to multiple
receivers. PGM guarantees that a receiver in a multicast group either receives all data packets from
transmissions and retransmissions, or can detect unrecoverable data packet loss. PGM is intended as a
solution for multicast applications with basic reliability requirements. PGM has two main parts: a host
element (also referred to as the transport layer of the PGM protocol) and a network element (also referred
to as the network layer of the PGM protocol).
The transport layer of the PGM protocol has two main parts: a source part and a receiver part. The
transport layer defines how multicast applications send and receive reliable, ordered, duplicate-free
multicast data from multiple sources to multiple receivers. PGM Host is the Cisco implementation of the
transport layer of the PGM protocol.
The network layer of the PGM protocol defines how intermediate network devices (such as routers and
switches) handle PGM transport data as the data flows through a network. PGM Router Assist is the
Cisco implementation of the network layer of the PGM protocol.