Differences

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--- general:network:frrouting [2021/05/10 07:26] – sunkan
+++ general:network:frrouting [2021/05/10 08:52] (current) – sunkan
@@ Line 16: / Line 16: @@
 #define ZEBRA_IBGP_DISTANCE_DEFAULT      200
 </code>
+Also documentation from latest release is available here [[http://docs.frrouting.org/en/latest/zebra.html#administrative-distance|FRR administrative distance]]
+====== Administrative Distance ======
+Administrative distance allows FRR to make decisions about what routes should be installed in the rib based upon the originating protocol. The lowest Admin Distance is the route selected. This is purely a subjective decision about ordering and care has been taken to choose the same distances that other routing suites have choosen.
+<code>
+Protocol     Distance
+System       0
+Kernel       0
+Connect      0
+Static       1
+NHRP        10
+EBGP        20
+EIGRP       90
+BABEL      100
+OSPF       110
+ISIS       115
+OPENFABRIC 115
+RIP        120
+Table      150
+SHARP      150
+IBGP       200
+PBR        200
+</code>
+An admin distance of 255 indicates to Zebra that the route should not be installed into the Data Plane. Additionally routes with an admin distance of 255 will not be redistributed.
+Zebra does treat Kernel routes as special case for the purposes of Admin Distance. Upon learning about a route that is not originated by FRR we read the metric value as a uint32_t. The top byte of the value is interpreted as the Administrative Distance and the low three bytes are read in as the metric. This special case is to facilitate VRF default routes.