Cisco WS-C4507R Troubleshooting Manual page 50

RST-3508
9805_05_2004_c2
RST-3508
9805_05_2004_c2
© 2004 Cisco Systems, Inc. All rights reserved. Printed in USA.
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Cisco IOS-Based Supervisor
QoS Flow Summary
Classification Based on:
Default DSCP Port Setting
Port "Trusted" CoS or DSCP
Layer 2/3/4 ACLs
Shared
RX
Classify
Memory
In-Coming
Dynamic Buffer Limiting
Encapsulation
(Supervisor II Plus
Can Be 802.1Q,
Supervisor IV
802.1p, ISL,
Supervisor V )
or None
Congestion Avoidance
© 2004 Cisco Systems, Inc. All rights reserved.
Tx Queuing and Scheduling
Q1
Q2
DSCP to
Q3
Queue Map
Q4
Queue selection based on "internal DSCP"
•
Default DSCP on port
Trust CoS/DSCP
Via service policies
Switch-wide DSCP to Tx queue map, not per-port!
•
Shaping: Max rate per queue
•
Sharing: Min rate per queue
•
Strict priority on queue 3
•
All in hardware at wire rate
•
© 2004 Cisco Systems, Inc. All rights reserved.
Policing via ACLs
Police Action:
Mark
Drop
Based:
Byte Rate
Burst
(Token Bucket)
Rewrite
Police DBL
Info
Rewrites TOS
Field in IP
Header and
802.1p/ISL
CoS Field
Sharing,
Strict Priority
Sharing and Shaping
and Strict Priority Q3
to Schedule Between
Output Queues
Queue 1
Queue 2
Sched TX
Queue 3
Queue 4
Out-Going
Encapsulation
Can Be 802.1Q,
802.1p, ISL,
or None
99 99 99
Ethernet
MAC
100 100 100