HP 3500YL - Manual (Page 237)

IP Routing Features
Configuring OSPF
3. 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 covered by
this guide, 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,
then all routers in the domain must be configured to support RFC 1583.
N o t e The routing switch is configured, by default, to be compliant with the RFC
1583 OSPF V2 specification. (Use
show ip ospf general to view the current RFC
1583 configuration setting.)
All routes in an AS should be configured with the same compliance setting for
preference rules affecting external routes. Thus, if any routers in an OSPF
domain support only RFC 1583, then all routers must be configured with 1583
compatibility. In the default OSPF configuration, RFC 1583 support is enabled
for the routing switches covered by this guide.
If all routers in the domain support RFC 2178 or RFC 2328, then you should
disable RFC 1583 compatibility on all of the routers, since conformance to
these later RFCs provides more robust protection against routing loops on
external routes.
Syntax: [no] rfc1583-compatibility
Executed at the global configuration level to toggle routing
switch operation compliance between RFC 1583 and RFC
2328.
rfc1583-compatibility: Configures the routing switch for external
route preference rules compliant with RFC 1583.
no rfc1583-compatibility: Configures the routing switch for
external route preference rules compliant with RFC 2328.
Default: Compliance enabled
For example, to disable RFC 1583 compatibility on a routing switch in an OSPF
domain where RFC 2178 and RFC 2328 are universally supported:
ProCurve(config)# router ospf
ProCurve(ospf)# no rfc1583-compatibility
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