Troubleshooting guide

11-54
ATM and Layer 3 Switch Router Troubleshooting Guide
OL-1969-01
Chapter 11 Troubleshooting Layer 3 Network Connections
Troubleshooting Route Processor Route Table and Utilization Problems
Bootstraps: 0/0, Candidate_RP_Advertisements: 0/0
IGMP statistics: Sent/Received
Total: 27/0, Format errors: 0/0, Checksum errors: 0/0
Host Queries: 13/0, Host Reports: 13/0, Host Leaves: 1/0
DVMRP: 0/0, PIM: 0/0
IGRP statistics:
Rcvd: 0 total, 0 checksum errors
Sent: 0 total
ARP statistics:
Rcvd: 6481 requests, 1388 replies, 0 reverse, 0 other
Sent: 1465 requests, 29954 replies (42 proxy), 0 reverse
C8540CSR-1#
Step 5 Check, for example, TCP packets with options set, UDP broadcasts or packets with checksum errors,
and ARP packets.
Step 6 For IPX routing, use the show ipx traffic command to check if the packets sent to the route processor
are being processed.
Switch# show ipx traffic
System Traffic for 0.0000.0000.0001 System-Name: domino
Rcvd: 0 total, 0 format errors, 0 checksum errors, 0 bad hop count,
0 packets pitched, 0 local destination, 0 multicast
Bcast: 0 received, 0 sent
Sent: 0 generated, 0 forwarded
0 encapsulation failed, 0 no route
SAP: 0 Total SAP requests, 0 Total SAP replies, 0 servers
0 SAP general requests, 0 ignored, 0 replies
0 SAP Get Nearest Server requests, 0 replies
0 SAP Nearest Name requests, 0 replies
0 SAP General Name requests, 0 replies
0 SAP advertisements received, 0 sent, 0 Throttled
0 SAP flash updates sent, 0 SAP format errors
Step 7 Check Bcast, Get Nearest Server (GNS), checksum errors, bad hop count.
Troubleshooting Route Processor Selective Packet Discard Problems
Selective Packet Discard (SPD) is used in the Layer 3 enabled ATM switch router when the following
occurs:
• A route or interface flap will cause a burst of packets to be process-switched until the CAM or
ternary CAM (TCAM) cache is repopulated.
• The switch router is switching a high volume of traffic, which may cause the input queue to overrun
and eventually throttle the interface.
• Packets are blindly dropped, which may affect routing updates and keepalives, causing more
invalidations.
SPD avoids dropping high precedence packets:
• Beyond a given threshold of queuing the input queue, packets with a low precedence are randomly
dropped, and then always dropped if queuing persists.