All things related to multicast

[Paul Chang <>]

Folks,

Anyone has similar problem on this?

When Powerquest drivemage set TTL=1, the nearest L3 switch (6513 in this 
case) has CPU utilization goes beyond 98%. If I adjusted the TTL=x to 
match how many hop the RP is, both the nearest L3 switch and RP has high 
CPU utilzation goes beyond 90%. The switch did not die in this case, but 
all software relate process were crawling.

My work-around is to turn off the "ip PIM sparse-mode" at the vlan where 
Mcast source and destinations are taken place (all within on vlan). This 
works fine since L2 Cisco 35xx has IGMP-snooping turned on. Usually, 1 
/40 source/destination ratio for computer lab imaging building is 
conducted.

I have Cisco TAC given me the followings

http://www.cisco.com/en/US/products/hw/switches/ps708/products_white_paper0900aecd802ca5d6.shtml

Some data-plane traffic may have to be processed in software as well. 
This type of traffic is referred to as data-plane "punt" traffic. 
Examples of software-processed data-plane packets include:

• Packets with IP options

• Packets with time-to-live (TTL) field equal to 1


which looks to me a design flaw of the control plane.

Anyone has a better way to deal with this? Please advice,

P a u l C h a n g Network Engineer
University of New Mexico
Computer & Information Resources & Technology
2701 Campus Boulevard NE, Albuquerque, NM 87131
Phone: (505) 277-8257 FAX: (505) 277-8101