Brocade Multi-Service IronWare Switching Configuration Guide (Supporting R05.6.00) - Manual (Page 808)

778 Multi-Service IronWare Switching Configuration Guide
53-1003036-02
Configuring forwarding parameters
19
Configuring IP source guard CAM partition
IP Source Guard creates two CAM sub-partitions. The CAM sub-partitions include
IP_SOURCE_GUARD_PERMIT and IP_SOURCE_GUARD_DENY. All CAM entries that are permitted,
go to the IP_SOURCE_GUARD_PERMIT sub-partition. All CAM entries that are denied, go to the
IP_SOURCE_GUARD_DENY sub-partition. The system-max ip-source-guard-cam command allows
you to control the size of both IP_SOURCE_GUARD_PERMIT and IP_SOURCE_GUARD_DENY
sub-partitions.
To specify a partition size of the IP Source Guard CAM, enter the following command.
Brocade(config)#system-max ip-source-guard-cam 1008
Syntax: [no] system-max [ip-source-guard-cam decimal]
By default, no system-max is configured.
The decimal variable specifies the range that is supported for configuring IP Source Guard CAM
sub-partitions. The decimal range is from 0 to 131072. The default is 0.
Configuring forwarding parameters
The following configurable parameters control the forwarding behavior of the Brocade device:
• Time-To-Live (TTL) threshold
• Forwarding of directed broadcasts
• Forwarding of source-routed packets
• Ones-based and zero-based broadcasts
All these parameters are global and thus affect all IP interfaces configured on the Brocade device.
To configure these parameters, use the procedures in the following sections.
Changing the TTL threshold
The TTL threshold prevents routing loops by specifying the maximum number of router hops an IP
packet originated by the Brocade device can travel through. Each device capable of forwarding IP
that receives the packet decreases the packet’s TTL by one. If a device receives a packet with a TTL
of 1 and reduces the TTL to zero, the device drops the packet.
The default TTL is 64. You can change the TTL to a value from 1– 255.
To modify the TTL threshold to 25, enter the following commands.
Brocade(config)# ip ttl 25
Syntax: [no] ip ttl 1-255
Enabling forwarding of directed broadcasts
A directed broadcast is an IP broadcast to all devices within a single directly-attached network or
subnet. A net-directed broadcast goes to all devices on a given network. A subnet-directed
broadcast goes to all devices within a given subnet.