NOTE: This section applies only to routing switches that are running software release 07.1.X or higher.
The IP forwarding cache provides fast-path forwarding for IP traffic. The entries in the cache contain the following information:
• Source IP address and TCP or UDP port • Destination IP address and TCP or UDP port
The default cache settings are adequate for most situations. However, if the routing switch forwards traffic to a very large number of destination hosts or uses default routes to send traffic to a large number of destinations, you may need to adjust the cache settings.
The software on chassis routing switches allows you to adjust the following forwarding cache settings:
• Cache capacity for unicast forwarding entries – The forwarding cache contains a unique entry for each host destination. You can set the cache to allow more unicast forwarding entries by enabling the high
performance mode. This option enables the cache to contain more unique entries for unicast traffic. • Cache format for default route entries – The forwarding cache contains a unique entry for each host
destination of a default route. You can increase the cache’s capacity for default route entries by enabling the
default-route aggregation mode. This option increases the cache’s capacity for default routes by aggregating forwarding information for multiple destinations into single default-route entries. These optimization options are disabled by default. To enable them, use the following procedures. Enabling Unicast High-Performance Mode
NOTE: To place a change to the high-performance mode into effect, you must reload the software after saving the change to the startup-config file.
USING THE CLI
To enable the high-performance mode, enter the following command: HP9300(config)# ip high-perf
HP9300(config)# write memory HP9300(config)# end
HP9300# reload
Syntax: [no] ip high-perf
To disable the high-performance mode, enter the following command: HP9300(config)# no ip high-perf
HP9300(config)# write memory HP9300(config)# end
HP9300# reload
USING THE WEB MANAGEMENT INTERFACE
You cannot configure this option using the Web management interface. Enabling the Default-Route Aggregation Mode
By default, the IP forwarding cache of a routing switch contains a unique entry for each host destination of a default route. You can increase the cache’s capacity for default route entries by enabling the default-route aggregation mode. This option increases the cache’s capacity for default routes by aggregating forwarding information for multiple destinations into single default-route entries.
When you enable default route aggregation, the routing switch associates a network prefix length with each forwarding cache entry that is based on a default network route.
The routing switch reprograms the default route cache entries if external events cause a conflict between entries. To configure the forwarding cache to aggregate entries for default route destinations, use the following CLI method.
NOTE: You do not need to reload the software to place a change to default-route aggregation into effect.
USING THE CLI
To enable the default-route aggregation mode, enter the following command: HP9300(config)# ip dr-aggregate
Syntax: [no] ip dr-aggregate
To disable the default-route aggregation mode, enter the following command: HP9300(config)# no ip dr-aggregate
USING THE WEB MANAGEMENT INTERFACE
You cannot configure this option using the Web management interface. Displaying the Forwarding Cache Entries for Default Routes
To display the default route entries in the IP forwarding cache, use the following CLI method. This method enables you to display the default route entries without displaying other types of forwarding entries.
NOTE: To display other types of forwarding cache entries, see “Displaying the Forwarding Cache” on page 6-88.
USING THE CLI
HP9300(config)# show ip dr-aggregate
Syntax: show ip dr-aggregate [<ip-addr>]
If you specify an IP address, only the entries for that destination are displayed. Here is an example of the information displayed by this command.
HP9300(config)# show ip dr-aggregate Total number of cache entries: 2
Start index: 1 D:Dynamic P:Permanent F:Forward U:Us C:Complex Filter W:Wait ARP I:ICMP Deny K:Drop R:Fragment S:Snap Encap
IP Address Next Hop MAC Type Port Vlan Pri
1 22.22.22.22 /8 207.95.6.60 0044.052e.4302 DF 1/1 1 0
2 207.96.7.7 /12 207.95.6.60 0044.052e.4302 DF 1/1 1 0
This example shows two entries. The prefix associated with each entry is displayed. Notice that the prefix lengths in this example are different for each entry. The software selects a prefix length long enough to make the default network route entry unambiguous, so that is does not conflict with other cache entries.
To display the entry for a specific destination, enter the destination address, as shown in the following example. HP9300(config)# show ip dr-aggregate 207.96.7.7
Total number of cache entries: 2
Start index: 1 D:Dynamic P:Permanent F:Forward U:Us C:Complex Filter W:Wait ARP I:ICMP Deny K:Drop R:Fragment S:Snap Encap
IP Address Next Hop MAC Type Port Vlan Pri
1 207.96.7.7 /12 207.95.6.60 0044.052e.4302 DF 1/1 1 0
This example shows the second entry from the previous example, but the entry row number is 1. The row number identifies the row number in the displayed output. In addition, notice that the Total number of cache entries field shows 2, as in the previous example. The number in this field indicates the total number of default route aggregation entries in the forwarding cache.
USING THE WEB MANAGEMENT INTERFACE
You cannot display the default-route cache entries using the Web management interface. Clearing the Forwarding Cache Entries for Default Routes
You can clear the default route entries from the IP forwarding cache. To do so, use the following CLI method.
NOTE: This command does not affect other types of forwarding cache entries.
USING THE CLI
To clear the default-route cache entries, enter the following command from the Privileged EXEC level of the CLI: HP9300# clear ip dr-aggregate
Syntax: clear ip dr-aggregate
USING THE WEB MANAGEMENT INTERFACE
You cannot clear the entries using the Web management interface.