Troubleshooting guide

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ATM and Layer 3 Switch Router Troubleshooting Guide
OL-1969-01
Chapter 11 Troubleshooting Layer 3 Network Connections
Troubleshooting Layer 3 IP Multicast Switching
For detailed configuration information see the IOS document, Configuring IP Multicast Routing.
IP Multicast Troubleshooting Commands
To troubleshoot an IP multicast problem, use the following commands:
IP multicast troubleshooting is similar to IP troubleshooting. The key is to check the consistency
between the route processor table information and CAM tables on the interfaces.
Follow these steps to troubleshoot IP multicast problems:
Step 1 Use the show epc if-entry command to display information about VC status:
C8540CSR-1# show epc if-entry interface fastethernet 1/0/15 entry gigabitethernet 0/0/0
IF Entry for GigabitEthernet0/0/0 on FastEthernet1/0/15
Mac(hex) - 00:90:21:41:BC:07
isMyInteface : False isSubInterface : False
Status Up Broute VC - 67 Bcast VC - 0
Netmask: 24
FEC disabled
Trunking Disabled
State : Not-Applicable/Listening/Blocking
Bridge-Group disabled
IP routing on bridging off
IPX routing off bridging off
Appletalk routing off
In Encapsulation:
ICMP Redirect enabled Unreachable enabled
IP Multicast enabled: ttl-threshold: 5
Command Purpose
show interfaces {fastethernet | gigabitethernet}
slot/subslot/port
(on the ingress interface)
Displays interface configuration, status, and
statistics on the ingress interface.
show interfaces {fastethernet | gigabitethernet}
slot/subslot/port
(on the egress interface)
Displays interface configuration, status, and
statistics on the egress interface.
show ip mroute Displays the IP multicast routing table.
show epc if-entry interface {fastethernet |
gigabitethernet} slot/subslot/port all
(on the ingress interface)
Displays all interface entry information for the
ingress interface.
show epc ipmcast groupaddr all interface
{fastethernet | gigabitethernet} slot/subslot/port
Displays the IP multicast routing table
information stored on the ingress interface for a
particular group IP address.
show epc ipmcast groupaddr detail interface
{fastethernet | gigabitethernet}
Displays detailed IP multicast routing table
information stored on the ingress interface for a
particular group and source IP address.
show atm vc cast-type p2mp interface
{fastethernet | gigabitethernet} slot/subslot/port
Displays the ATM VC cast type point to
multi-point configuration for a specific
interface.