3.13. OSPF Route Table Use (original) (raw)

Connected: An Internet Encyclopedia
3.13. OSPF Route Table Use

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3.13. OSPF Route Table Use

-- OSPF Use of the CIDR Route Table

ospfRouteGroup OBJECT IDENTIFIER ::= { ospf 13 }

-- The IP Forwarding Table defines a number of objects for use by -- the routing protocol to externalize its information. Most of -- the variables (ipForwardDest, ipForwardMask, ipForwardPolicy, -- ipForwardNextHop, ipForwardIfIndex, ipForwardType, -- ipForwardProto, ipForwardAge, and ipForwardNextHopAS) are -- defined there.

-- Those that leave some discretion are defined here.

-- ipCidrRouteProto is, of course, ospf (13).

-- ipCidrRouteAge is the time since the route was first calculated, -- as opposed to the time since the last SPF run.

-- ipCidrRouteInfo is an OBJECT IDENTIFIER for use by the routing -- protocol. The following values shall be found there depending -- on the way the route was calculated.

ospfIntraArea OBJECT IDENTIFIER ::= { ospfRouteGroup 1 } ospfInterArea OBJECT IDENTIFIER ::= { ospfRouteGroup 2 } ospfExternalType1 OBJECT IDENTIFIER ::= { ospfRouteGroup 3 } ospfExternalType2 OBJECT IDENTIFIER ::= { ospfRouteGroup 4 }

-- ipCidrRouteMetric1 is, by definition, the primary routing -- metric. Therefore, it should be the metric that route -- selection is based on. For intra-area and inter-area routes, -- it is an OSPF metric. For External Type 1 (comparable value) -- routes, it is an OSPF metric plus the External Metric. For -- external Type 2 (non-comparable value) routes, it is the -- external metric.

-- ipCidrRouteMetric2 is, by definition, a secondary routing -- metric. Therefore, it should be the metric that breaks a tie -- among routes having equal metric1 values and the same -- calculation rule. For intra-area, inter-area routes, and -- External Type 1 (comparable value) routes, it is unused. For -- external Type 2 (non-comparable value) routes, it is the metric -- to the AS border router.

-- ipCidrRouteMetric3, ipCidrRouteMetric4, and ipCidrRouteMetric5 are -- unused.

Next: 3.14. OSPF Area Aggregate Table

Connected: An Internet Encyclopedia
3.13. OSPF Route Table Use