Cabletron Systems CoreWatch, User Manual

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Chapter 20: Checking the Status of Routing Tables
428 CoreWatch User’s Manual
Obtaining IGMP Cache Information
Obtain IGMP Cache information if you want to learn about the multicast groups of IGMP
interfaces, identify whether the SSR is a member of those groups, and examine other
IGMP configuration information about those groups. To access such information:
1. If you are not in the Front Panel view, switch to it by clicking the CoreWatch main
window.
2. Select the Monitor menu, choose Routing State , choose IGMP State , and then choose
IGMP Cache Table .
An IGMP Cache table similar to the following appears:
Figure 269. IGMP Cache table
Joins Indicates how many times a group membership has been
added on the interface. By examining this field, you can
determine the amount of IGMP activity over time.
Groups Indicates how many groups are on the interface.
Robustness Indicates the expected packet loss on a subnet. Robustness is a
measurement of a lossy network condition. The SSR assumes a
robustness of 2.
Table 70. IGMP Interface table fields (Continued)
Field Description