Changing The Lsp Interval And Retransmit Interval; Changing The Spf Timer; Globally Disabling Or Re-Enabling Hello Padding - Dell PowerConnect B-RX Configuration Manual

Changing the LSP interval and retransmit interval

You LSP interval is the rate of transmission, in milliseconds of the LSPs. The retransmit interval is
the time the device waits before it retransmits LSPs. To define an LSP interval, enter a command
such as the following.
BigIron RX(config-isis-router)# lsp-interval 45
Syntax: [no] lsp-interval <milliseconds>
Enter 1 – 4294967295 milliseconds for the LSP interval. The default is 33 milliseconds.
To define an interval for retransmission of LSPs enter a command such as the following.
BigIron RX(config-isis-router)# etransmit-interval 3
Syntax: [no] retransmit-interval <seconds>
Enter 0 – 65535 seconds for the retransmission interval. The default is 5 seconds.

Changing the SPF timer

Every IS maintains a Shortest Path First (SPF) tree, which is a representation of the states of each
of the IS's links to ESs and other ISs. If the IS is both a Level-1 and Level-2 IS, it maintains separate
SPF trees for each level.
To ensure that the SPF tree remains current, the IS updates the tree at regular intervals following a
change in network topology or the link state database. By default, the device recalculates its IS-IS
tree every five seconds following a change. You can change the SPF timer to a value from 1 – 120
seconds.
To change the SPF interval, enter a command such as the following.
BigIron RX(config-isis-router)# spf-interval 30
Syntax: [no] spf-interval <secs>
The <secs> parameter specifies the interval and can be from 1 – 120 seconds. The default is 5
seconds.

Globally disabling or re-enabling hello padding

By default, the 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 device supports.
The padding applies to the following types of hello packets:
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•
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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.
BigIron RX Series Configuration Guide
53-1001810-01
ES hello (ESH PDU)
IS hello (ISH PDU)
IS to IS hello (IIH PDU)
Globally configuring IS-IS on a device
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