diff options
| -rw-r--r-- | doc/user/zebra.rst | 56 | ||||
| -rw-r--r-- | tests/topotests/all-protocol-startup/r1/ipv4_routes.ref | 1 | ||||
| -rw-r--r-- | tests/topotests/all-protocol-startup/r1/ipv6_routes.ref | 3 | ||||
| -rw-r--r-- | tests/topotests/all-protocol-startup/r1/zebra.conf | 7 |
4 files changed, 65 insertions, 2 deletions
diff --git a/doc/user/zebra.rst b/doc/user/zebra.rst index 50c518d456..d54ca2a81e 100644 --- a/doc/user/zebra.rst +++ b/doc/user/zebra.rst @@ -292,6 +292,62 @@ Link Parameters Commands .. _zebra-vrf: +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. + ++------------+-----------+ +| 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 | ++------------+-----------+ + +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. + Virtual Routing and Forwarding ============================== diff --git a/tests/topotests/all-protocol-startup/r1/ipv4_routes.ref b/tests/topotests/all-protocol-startup/r1/ipv4_routes.ref index 0a20231371..a7d6fe11a6 100644 --- a/tests/topotests/all-protocol-startup/r1/ipv4_routes.ref +++ b/tests/topotests/all-protocol-startup/r1/ipv4_routes.ref @@ -15,6 +15,7 @@ S>* 4.5.6.11/32 [1/0] via 192.168.0.2, r1-eth0, XX:XX:XX S>* 4.5.6.12/32 [1/0] is directly connected, r1-eth0, XX:XX:XX S>* 4.5.6.13/32 [1/0] unreachable (blackhole), XX:XX:XX S>* 4.5.6.14/32 [1/0] unreachable (blackhole), XX:XX:XX +S 4.5.6.15/32 [255/0] via 192.168.0.2, r1-eth0, XX:XX:XX S>* 4.5.6.7/32 [1/0] unreachable (blackhole), XX:XX:XX S>* 4.5.6.8/32 [1/0] unreachable (blackhole), XX:XX:XX S>* 4.5.6.9/32 [1/0] unreachable (ICMP unreachable), XX:XX:XX diff --git a/tests/topotests/all-protocol-startup/r1/ipv6_routes.ref b/tests/topotests/all-protocol-startup/r1/ipv6_routes.ref index 6e3e9c87c1..d5bc16a2bf 100644 --- a/tests/topotests/all-protocol-startup/r1/ipv6_routes.ref +++ b/tests/topotests/all-protocol-startup/r1/ipv6_routes.ref @@ -20,9 +20,10 @@ C * fe80::/64 is directly connected, r1-eth7, XX:XX:XX C * fe80::/64 is directly connected, r1-eth8, XX:XX:XX C * fe80::/64 is directly connected, r1-eth9, XX:XX:XX O fc00:0:0:4::/64 [110/10] is directly connected, r1-eth4, XX:XX:XX -S>* 4:5::/32 [1/0] is directly connected, r1-eth0, XX:XX:XX S>* 4:5::6:10/128 [1/0] via fc00::2, r1-eth0, XX:XX:XX S>* 4:5::6:11/128 [1/0] via fc00::2, r1-eth0, XX:XX:XX +S>* 4:5::6:12/128 [1/0] is directly connected, r1-eth0, XX:XX:XX +S 4:5::6:15/128 [255/0] via fc00::2, r1-eth0, XX:XX:XX S>* 4:5::6:7/128 [1/0] unreachable (blackhole), XX:XX:XX S>* 4:5::6:8/128 [1/0] unreachable (blackhole), XX:XX:XX S>* 4:5::6:9/128 [1/0] unreachable (ICMP unreachable), XX:XX:XX diff --git a/tests/topotests/all-protocol-startup/r1/zebra.conf b/tests/topotests/all-protocol-startup/r1/zebra.conf index c621593ef7..85c8676964 100644 --- a/tests/topotests/all-protocol-startup/r1/zebra.conf +++ b/tests/topotests/all-protocol-startup/r1/zebra.conf @@ -20,7 +20,12 @@ ip route 4.5.6.11/32 192.168.0.2 r1-eth0 ipv6 route 4:5::6:11/128 fc00:0:0:0::2 r1-eth0 # Create ifname routes ip route 4.5.6.12/32 r1-eth0 -ipv6 route 4:5::6:12/32 r1-eth0 +ipv6 route 4:5::6:12/128 r1-eth0 +# Create a route that has a large admin distance +# an admin distance of 255 should be accepted +# by zebra but not installed. +ip route 4.5.6.15/32 192.168.0.2 255 +ipv6 route 4:5::6:15/128 fc00:0:0:0::2 255 ! interface r1-eth0 description to sw0 - no routing protocol |