Brocade Multi-Service IronWare Routing Configuration Guide (Supporting R05.6.00) - Manual (Page 292)

264 Multi-Service IronWare Routing Configuration Guide
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Globally configuring IS-IS on a device
The second-wait variable is an optional value that specifies the wait time between the first and
second PSPF calculations. If this optional value is configured, it will be doubled with each PSPF
recalculation until the value is equal to the spf-max-wait value. The range of acceptable values is
0 – 120000 milliseconds. The default for this variable is value of the max-wait time.
Configuring the IS-IS flooding mechanism
The IS-IS fast flooding feature allows you to configure IS-IS on the router to flood Link State PDUs to
other routers in the network before running SPF. This improves database synchronization by
allowing LSP changes to be propagated to neighbors before running SPF. The IS-IS fast-flood
feature is implemented using the fast-flood command as shown in the following.
Brocade(config-isis-router)# fast-flood 10
Syntax: [no] fast-flood lsp-count
The lsp-count variable sets the number of LSPs that trigger SPF that must be flooded before
running SPF. The SPF run will be delayed until the configured number of LSPs have been flooded. If
the number of changed LSPs is less than the configured number, then only the changed LSPs are
flooded. The variable can be set to the following values: 1 - 25. This variable is optional and will be
set to a value of 4 if not specified.
Globally disabling or re-enabling hello padding
By default, the Brocade device adds extra data to the end of a hello packet to make the packet the
same size as the maximum length of PDU the Brocade device supports.
The padding applies to the following types of hello packets:
• ES hello (ESH PDU)
• IS hello (ISH PDU)
• IS to IS hello (IIH PDU)
The padding consists of arbitrarily valued octets. A padded hello PDU indicates the largest PDU that
the Brocade device can receive. Other ISs that receive a padded hello PDU from the Brocade device
can therefore ensure that the IS-IS PDUs they send the Brocade device. Similarly, if the Brocade
device receives a padded hello PDU from a neighbor IS, the Brocade device knows the maximum
size PDU that the Brocade device can send to the neighbor.
When padding is enabled, the maximum length of a Hello PDU sent by the Brocade device is 1514
bytes.
If you need to disable padding, you can do so globally or on individual interfaces. Generally, you do
not need to disable padding unless a link is experiencing slow performance. If you enable or
disable padding on an interface, the interface setting overrides the global setting.
To globally disable padding of IS-IS hello PDUs, enter the following command.
Brocade(config-isis-router)# no hello padding
This command disables all hello PDU padding on the Brocade device. To re-enable padding, enter
the following command.
Brocade(config-isis-router)# hello padding
Syntax: [no] hello padding [point-to-point]
By default, hello padding is enabled. Enter the no form of the command to disable hello padding.