Source-Specific Multicast (SSM) provides network-layer support for one-to-many delivery of data (and not many-to-many). IP addresses in the range 126.96.36.199 to 188.8.131.52 (address block 232/8) are currently reserved for use as SSM destination addresses. Following graphs display some basic statistics related to the usage of SSM addresses.
List of Available Graphs:
A very brief introduction to SSM addressing and scoping:
Any application/host interested in contents being delivered via SSM specifically requests for corresponding channel. As each channel is identified as a Source-address and Group-address tuple; i.e. (S,G); there is no possibility of two hosts initiating the same channel. Thus, there is no need of using special group-addresses for administrative scoping. However, such scoping can be implemented within a domain by filtering at domain routers.
Utility of the results and how to interpret the graphs:
Results presented on this page are based on the statistics collected from mroute tables as well as MSDP tables. As no SSM groups shall be advertised via MSDP, results presented on this page depict SSM-usage strictly from the point of view of the monitored routers. In an ideal case, only those groups, data for which flows through at least one of the monitored routers, shall contribute to the results presented here. However, several times advertisement for SSM groups does seep in as MSDP announcements. This situation arises because of buggy deployment and can be noticed in the graphs with the help of the plot, "#232/8's Advertized via MSDP".