Troubleshooting guide

13-31
ATM and Layer 3 Switch Router Troubleshooting Guide
OL-1969-01
Chapter 13 Troubleshooting ATM Router Module Connections
Troubleshooting IP Multicast on ATM Router Module Connections
– The routing or bridging layer is informed to remove routes or MAC addresses learned over the
affected VC
• On the router, the subinterface status and VC status change to DOWN
If you determine that the OAM interface is configured incorrectly, refer to the “Configuring Operation,
Administration, and Maintenance” chapter in the ATM Switch Router Software Configuration Guide.
Troubleshooting IP Multicast on ATM Router Module
Connections
IP multicast reduces traffic by simultaneously delivering a single stream of information to multiple
recipients. IP Multicast is only supported with 1483 LLC encapsulation (AAL5SNAP).
Figure 13-12 is an example network using IP multicast over ATM switch routers with ATM router
modules.
Figure 13-12IP Multicast with the ATM Router Module Example Network
Figure 13-12 shows source router A connected with Non-ATM interfaces (for example, Ethernet
interfaces) to ATM switch routers B and C with ATM router modules installed. The Cat 8540 MSR
switches have 1483 multiplex PVCs configured as cross-connects between the ATM router module II
and ATM interfaces.
Figure 13-12 shows a basic scenario where IP multicast traffic flows between Ethernet connections using
the ATM cloud. If router A is the IP multicast source and routers D and E are multicast destinations, a
multicast packet that enters ATM switch router B is switched to the ATM router module II interface. The
ATM router module II then encapsulates the packet, using either 1483 SNAP or multiplex (with no 1483
header), depending on the type of PVC configured between the ATM router module II and outgoing ATM
interface. The packet is then transmitted out to ATM cloud where ATM switch router C receives the ATM
traffic. The ATM router module II on ATM switch router C switches the packet out the corresponding
Ethernet interfaces after removing the1483 headers.
Note The switch fabric is used for packet replication between the ATM router module II and the egress
Ethernet interfaces.
Source
router
A
Destination
router
D
Destination
router
E
ATM switch router
with ARM II
B
ATM switch router
with ARM II
C
68401
ATM 3/0/1
VPI 0, VCI 50
ATM 0/0/1
VPI 1, VCI 60
Ethernet Ethernet
Ethernet