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authorDonald Sharp <sharpd@cumulusnetworks.com>2017-10-18 10:24:28 -0400
committerDavid S. Miller <davem@davemloft.net>2017-10-20 13:03:03 +0100
commit17c918840fb07e5819f8df03345d7f4a5e5b791c (patch)
treece6a93f3abc9d42f97b99c04ed180a561f6814de /Documentation/networking
parent9854d758f7215ceea7da625cb421e0674846b53c (diff)
doc: Update VRF documentation metric
Two things: 1) Update examples to show usage of metric 2) Discuss reasoning for using such a high metric. Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com> Acked-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation/networking')
-rw-r--r--Documentation/networking/vrf.txt13
1 files changed, 9 insertions, 4 deletions
diff --git a/Documentation/networking/vrf.txt b/Documentation/networking/vrf.txt
index 3918dae964d4..8ff7b4c8f91b 100644
--- a/Documentation/networking/vrf.txt
+++ b/Documentation/networking/vrf.txt
@@ -71,7 +71,12 @@ Setup
ip ru add iif vrf-blue table 10
3. Set the default route for the table (and hence default route for the VRF).
- ip route add table 10 unreachable default
+ ip route add table 10 unreachable default metric 4278198272
+
+ This high metric value ensures that the default unreachable route can
+ be overridden by a routing protocol suite. FRRouting interprets
+ kernel metrics as a combined admin distance (upper byte) and priority
+ (lower 3 bytes). Thus the above metric translates to [255/8192].
4. Enslave L3 interfaces to a VRF device.
ip link set dev eth1 master vrf-blue
@@ -256,7 +261,7 @@ older form without it.
For example:
$ ip route show vrf red
- prohibit default
+ unreachable default metric 4278198272
broadcast 10.2.1.0 dev eth1 proto kernel scope link src 10.2.1.2
10.2.1.0/24 dev eth1 proto kernel scope link src 10.2.1.2
local 10.2.1.2 dev eth1 proto kernel scope host src 10.2.1.2
@@ -282,7 +287,7 @@ older form without it.
ff00::/8 dev red metric 256 pref medium
ff00::/8 dev eth1 metric 256 pref medium
ff00::/8 dev eth2 metric 256 pref medium
-
+ unreachable default dev lo metric 4278198272 error -101 pref medium
8. Route Lookup for a VRF
@@ -331,7 +336,7 @@ function vrf_create
ip link add ${VRF} type vrf table ${TBID}
if [ "${VRF}" != "mgmt" ]; then
- ip route add table ${TBID} unreachable default
+ ip route add table ${TBID} unreachable default metric 4278198272
fi
ip link set dev ${VRF} up
}