12.
Optional: Configure OSPF interface authentication.
13.
Configure virtual links for any areas not directly connected to the backbone.
Configuration rules
• If the switch is to operate as an ASBR, you must enable redistribution (step 7 in
.
When you do that, ASBR capability is automatically enabled. For this reason, you should first configure
redistribution filters on the ASBR. Otherwise, all possible external routes will be allowed to flood the domain.
(See
Configuring external route redistribution in an OSPF domain (optional)
on page 205.)
• Each VLAN interface on which you want OSPF to run must be assigned to one of the defined areas. When a
VLAN interface is assigned to an area, the IP address is automatically included in the assignment. To include
additional addresses, you must enable OSPF on them separately, or use the "all" option in the assignment.
OSPF global and interface settings
When first enabling OSPF, you may want to consider configuring ranges and restricting redistribution (if an ASBR
is used) to avoid unwanted advertisements of external routes. You may also want to enable the OSPF trap and
authentication features to enhance troubleshooting and security. However, Hewlett Packard Enterprise generally
recommends that the remaining parameters with non-null default settings be left as-is until you have the
opportunity to assess OSPF operation and determine whether any adjustments to non-default settings is
warranted.
NOTE:
Set global level parameters in the
ospf
context of the CLI. To access this context level, ensure that
routing is enabled, then execute
router ospf
at the global CONFIG level. For example:
switch (config)# router ospf
switch (ospf)#
Use the VLAN interface context to set interface level OSPF parameters for the desired VLAN. To
access this context level, use
vlan vid
either to move to the VLAN context level or to specify that
context from the global config level. For example, both of the following command sets achieve the
same result:
switch(config)# vlan 20
switch(vlan-20)# cost 15
switch(config)# vlan 20 cost 15
Changing the RFC 1583 OSPF compliance setting
In OSPF domains supporting multiple external routes from different areas to the same external destination,
multiple AS-external-LSAs advertising the same destination are likely to occur. This can cause routing loops and
the network problems that loops typically generate. On the routing switches, if RFC 1583 compatibility is disabled,
the preference rules affecting external routes are those stated in RFC-2328, which minimize the possibility of
routing loops when AS-external-LSAs for the same destination originate from ASBRs in different areas. However,
because all routers in an OSPF domain must support the same routing-loop prevention measures, if the domain
includes any routers that support only RFC 1583 preference rules, all routers in the domain must be configured to
support RFC 1583.
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Aruba 3810 / 5400R Multicast and Routing Guide for ArubaOS-
Switch 16.08
