Cisco WS-C4507R Troubleshooting Manual page 60

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
Dynamic Buffer Limiting (DBL)
Congestion avoidance technique
•
Flow based and maintains flow table per queue
•
Operates by tracking buffer usage and credits
•
If buffer usage exceeds dynamically computed
•
limit, DBL can either drop or set explicit congestion
notification
Implemented in Cisco IOS supervisor hardware with
•
line-rate performance
The default DBL computation is very reliable; the
•
rule is not to tune the algorithm unless it is really
required and the reason understood
© 2004 Cisco Systems, Inc. All rights reserved.
Dynamic Buffer Limiting
BUFFERS
DBL
Aggressive
Buffer Limit
2 Pkts
FLOW
CREDITS
Max Credits
15 (Default)
Aggressive
Credit
Limit 10
T0 T1
NAF: Non Adaptive Flow
© 2004 Cisco Systems, Inc. All rights reserved.
Drop One
Packet
Classified NAF
T2 T3
119 119 119
Time
T4
120 120 120