Allied Telesis AT-S63 - Manual (Page 553)

AT-S63 Management Software Command Line Interface User’s Guide
Section VII: Internet Protocol Routing 553
Version 2 supports the addition of a password of up to sixteen
alphanumeric characters to protect routers and their tables from
incorporating bogus routing updates. The switch adds the password into
the routing table when it broadcasts the contents of the table to its
neighboring routing devices, which check the password prior to updating
their tables.
Note
A RIP version 2 password is sent in plaintext. The AT-S63
management software does not support encrypted RIP passwords.
The switch broadcasts its routing table every thirty seconds from those
interfaces that have RIP. This interval is not adjustable on the switch. The
entire table is sent with the following exceptions:
ˆ Dynamic RIP routes that fall under the split horizon rule.
ˆ Inactive interface routes where there are no active ports in the VLAN.
ˆ The default route.
Note
The AT-S63 management software does not support the RIP
holddown and flush timers.
The commands for managing RIP are “ADD IP RIP” on page 572,
“DELETE IP RIP” on page 578, and “SET IP RIP” on page 586.
Note
RIP must be configured from the command line interface. RIP is not
supported in the menus and web browser interfaces.
Routing Table
The switch maintains its routing information in a table of routes that tells
the switch how to find a local or remote destination. Each route is uniquely
identified in the table by its IP address, network mask, next hop, protocol,
and routing interface.
When the switch receives an IPv4 packet, it scans the routing table to find
the most specific route to the destination on an “up” interface where there
is at least one active port in the VLAN. If the switch does not find a direct
route to the remote destination and no default route exists, the switch
discards the packet and sends an ICMP message to that effect back to the
source.
The switch transmits its routing table every 30 seconds from those
interfaces that have RIP. The RIP timer is not adjustable. The switch also
transmits its routing table and resets the timer to zero whenever there is a
change to the table. This ensures that the neighboring routers are
immediately informed of updates to the table.