Dell Force10 E600i FTOS Version 8.4.1.5 Configuration Guide for ExaScale - Page 636

www.dell.com | support.dell.com Limit the Number of Multicast Routes Task Limit the total number of multicast routes on the system. Command Syntax ip multicast-limit Range: 1-50000 Default: 15000 Command Mode CONFIGURATION When the limit is reached, FTOS does not process any IGMP or MLD joins to PIM-though it still processes leave messages-until the number of entries decreases below 95% of the limit. When the limit falls below 95% after hitting the maximum, the system begins relearning route entries through IGMP, MLD, and MSDP. • If the limit is increased after it is reached, join subsequent join requests are accepted. In this case, you must increase the limit by at least 10% for IGMP and MLD to resume. • If the limit is decreased after it is reached, FTOS does not clear the existing sessions. Entries are cleared upon a timeout (you may also clear entries using clear ip mroute). Note: FTOS waits at least 30 seconds between stopping and starting IGMP join processing. You may experience this delay when manipulating the limit after it is reached. When the multicast route limit is reached, FTOS displays Message 1. Message 1 Multicast Route Limit Error 3w1d13h: %RPM0-P:RP2 %PIM-3-PIM_TIB_LIMIT: PIM TIB limit reached. No new routes will be learnt until TIB level falls below low watermark. 3w1d13h: %RPM0-P:RP2 %PIM-3-PIM_TIB_LIMIT: PIM TIB below low watermark. Route learning will begin. Note: The IN-L3-McastFib CAM partition is used to store multicast routes and is a separate hardware limit that is exists per port-pipe. Any software-configured limit might be superseded by this hardware space limitation. The opposite is also true, the CAM partition might not be exhausted at the time the system-wide route limit set by the ip multicast-limit is reached. Prevent a Host from Joining a Group You can prevent a host from joining a particular group by blocking specific IGMP reports. Create an extended access list containing the permissible source-group pairs. Use the command ip igmp access-group access-list-name from INTERFACE mode to apply the access list. Note: For rules in IGMP access lists, source is the multicast source, not the source of the IGMP packet. For IGMPv2, use the keyword any for source (as shown in Figure 33-2), since IGMPv2 hosts do not know in advance who the source is for the group in which they are interested. 636 | Multicast Features