Cpu Queues - Cisco WS-C4507R Troubleshooting Manual

RST-3508
9805_05_2004_c2
RST-3508
9805_05_2004_c2
© 2004 Cisco Systems, Inc. All rights reserved. Printed in USA.
Presentation_ID.scr
High CPU Usage: Cisco IOS Supervisors
CPU usage is not indicative of forwarding
•
performance on any supervisor
Forwarding decisions are made in hardware
•
Packets sent to the CPU
•
Control packets: STP, CDP, PAgP, LACP, UDLD
Routing protocol updates
IPX/Appletalk
SNMP/telnet/
ARP responses to ARP requests
Packets with IP options/expired TTL or non-ARPA encaps
Packets with special handling, i.e. tunneling, encryption
ACL logging enabled
Input ACL drops
MTU check failure
Adjacency same interface
© 2004 Cisco Systems, Inc. All rights reserved.
Extras: QoS on the CPU Port
Packets to
the CPU

CPU Queues

Protects important traffic when CPU usage is high
•
BPDUs/routing updates get priority
Can still telnet or SNMP query when CPU is high
© 2004 Cisco Systems, Inc. All rights reserved.
0: ESMP
1: Control
2: Host Learning
–
3 5: L3 Forwarding
...
–
9 10: L3 Rx (Telnet/SNMP)
15: MTU Fail/Invalid
31 31 31
32 32 32