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Most ACL rules require one entry in the CAM. However, rules with TCP and UDP
port operators (for example, gt, lt, or range) may require more than one entry. The
range of ports is configured in the CAM based on bit mask boundaries; the space
required depends on exactly what ports are included in the range.
Example
An ACL rule with a TCP port range of 4000–8000 uses eight entries in the CAM.
Rule# Data Mask From To #Covered
1 0000111110100000 1111111111100000 4000 4031 32
2 0000111111000000 1111111111000000 4032 4095 64
3 0001000000000000 1111100000000000 4096 6143 2048
4 0001100000000000 1111110000000000 6144 7167 1024
5 0001110000000000 1111111000000000 7168 7679 512
6 0001111000000000 1111111100000000 7680 7935 256
7 0001111100000000 1111111111000000 7936 7999 64
8 0001111101000000 1111111111111111 8000 8000 1
Total Ports: 4001
Example
An ACL rule with a TCP port lt 1023 uses only one entry in the CAM.
Rule# Data Mask From To #Covered
1 0000000000000000 1111110000000000 0 1023 1024
Total Ports: 1024
Related
Commands
ip access-list extended — creates an extended ACL.
permit — assigns a permit filter for IP packets.
permit udp — assigns a permit filter for UDP packets.
permit udp
To pass UDP packets meeting the filter criteria, configure a filter.
Z9500
Syntax
permit udp {source mask | any | host ip-address} [operator port
[port]] {destination mask | any | host ip-address} [dscp]
[operator port [port]] [count [bytes]] [order] [fragments] [log
[interval minutes] [threshold-in-msgs [count]][monitor]
To remove this filter, you have two choices:
• Use the no seq sequence-number command if you know the filter’s
sequence number.
• Use the no permit udp {source mask | any | host ip-address}
{
destination mask | any | host ip-address command.
Access Control Lists (ACL)
255