Dell BigIron RX Series, Configuration Manual

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BigIron RX Series Configuration Guide 879
53-1002253-01
Globally configuring IS-IS on a device
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The padding consists of arbitrarily valued octets. A padded hello PDU indicates the largest PDU that
the device can receive. Other ISs that receive a padded hello PDU from the device can therefore
ensure that the IS-IS PDUs they send the device. Similarly, if the device receives a padded hello
PDU from a neighbor IS, the device knows the maximum size PDU that the
device
can send to the
neighbor.
When padding is enabled, the maximum length of a Hello PDU sent by the
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.
BigIron RX(config-isis-router)# no hello padding
This command disables all hello PDU padding on the
device
. To re-enable padding, enter the
following command.
BigIron RX(config-isis-router)# hello padding
Syntax: [no] hello padding
By default, hello padding is enabled. Enter the no form of the command to disable hello padding.
To disable hello padding on an interface, refer to “Disabling and enabling hello padding on an
interface” on page 888.
Logging adjacency changes
The
device
can generate a Syslog entry and an SNMP trap to indicate a change in the status of
an adjacency with another IS. Logging of the adjacency changes is disabled by default. To enable or
disable them, use either of the following methods.
To enable logging of adjacency changes, enter the following command.
BigIron RX(config-isis-router)# log-adjacency-changes
Syntax: [no] log-adjacency-changes
To disable logging of adjacency changes, enter the following command.
BigIron RX(config-isis-router)# no log-adjacency-changes
Disabling partial SPF calculations
By default, IS-IS makes incremental changes to the routing table when changes to the network
occur. A full SPF calculation is not performed unless there is a substantial change in the network;
for example when an IS-IS link flaps in the network. You can optionally configure IS-IS to perform a
full SPF calculation when any changes occur in the network.
To disable partial SPF calculations for IS-IS, enter the following command.
BigIron RX(config-isis-router)# disable-partial-spf-opt
Syntax: [no] disable-partial-spf-opt