Provided by: iproute2_6.1.0-1ubuntu2_amd64 
NAME
ip-nexthop - nexthop object management
SYNOPSIS
ip [ ip-OPTIONS ] nexthop { COMMAND | help }
ip nexthop { show | flush } SELECTOR
ip nexthop { add | replace } id ID NH
ip nexthop { get | del } id ID
ip nexthop bucket list BUCKET_SELECTOR
ip nexthop bucket get id ID index INDEX
SELECTOR := [ id ID ] [ dev DEV ] [ vrf NAME ] [ master DEV ] [ groups ] [ fdb ]
BUCKET_SELECTOR := SELECTOR | [ nhid ID ]
NH := { blackhole | [ via ADDRESS ] [ dev DEV ] [ onlink ] [ encap ENCAP ] [ fdb ] | group
GROUP [ fdb ] [ type TYPE [ TYPE_ARGS ] ] }
ENCAP := [ ENCAP_MPLS ]
ENCAP_MPLS := mpls [ LABEL ] [ ttl TTL ]
GROUP := id[,weight[/...]
TYPE := { mpath | resilient }
TYPE_ARGS := [ RESILIENT_ARGS ]
RESILIENT_ARGS := [ buckets BUCKETS ] [ idle_timer IDLE ] [ unbalanced_timer UNBALANCED ]
DESCRIPTION
ip nexthop is used to manipulate entries in the kernel's nexthop tables.
ip nexthop add id ID
add new nexthop entry
ip nexthop replace id ID
change the configuration of a nexthop or add new one
via [ FAMILY ] ADDRESS
the address of the nexthop router, in the address family FAMILY. Address
family must match address family of nexthop instance.
dev NAME
is the output device.
onlink pretend that the nexthop is directly attached to this link, even if it does
not match any interface prefix.
encap ENCAPTYPE ENCAPHDR
attach tunnel encapsulation attributes to this route.
ENCAPTYPE is a string specifying the supported encapsulation type. Namely:
mpls - encapsulation type MPLS
ENCAPHDR is a set of encapsulation attributes specific to the ENCAPTYPE.
mpls
MPLSLABEL - mpls label stack with labels separated by /
ttl TTL - TTL to use for MPLS header or 0 to inherit from IP
header
group GROUP [ type TYPE [ TYPE_ARGS ] ]
create a nexthop group. Group specification is id with an optional weight
(id,weight) and a '/' as a separator between entries.
TYPE is a string specifying the nexthop group type. Namely:
mpath - Multipath nexthop group backed by the hash-threshold
algorithm. The default when the type is unspecified.
resilient - Resilient nexthop group. Group is resilient to addition
and deletion of nexthops.
TYPE_ARGS is a set of attributes specific to the TYPE.
resilient
buckets BUCKETS - Number of nexthop buckets. Cannot be changed for
an existing group
idle_timer IDLE - Time in seconds in which a nexthop bucket does
not see traffic and is therefore considered idle. Default is 120
seconds
unbalanced_timer UNBALANCED - Time in seconds in which a nexthop
group is unbalanced and is therefore considered unbalanced. The
kernel will try to rebalance unbalanced groups, which might result
in some flows being reset. A value of 0 means that no rebalancing
will take place. Default is 0 seconds
blackhole
create a blackhole nexthop
fdb nexthop and nexthop groups for use with layer-2 fdb entries. A fdb nexthop
group can only have fdb nexthops. Example: Used to represent a vxlan remote
vtep ip. layer-2 vxlan fdb entry pointing to an ecmp nexthop group
containing multiple remote vtep ips.
ip nexthop delete id ID
delete nexthop with given id.
ip nexthop show
show the contents of the nexthop table or the nexthops selected by some criteria.
dev DEV
show the nexthops using the given device.
vrf NAME
show the nexthops using devices associated with the vrf name
master DEV
show the nexthops using devices enslaved to given master device
groups show only nexthop groups
fdb show only fdb nexthops and nexthop groups
ip nexthop flush
flushes nexthops selected by some criteria. Criteria options are the same as show.
ip nexthop get id ID
get a single nexthop by id
ip nexthop bucket show
show the contents of the nexthop bucket table or the nexthop buckets selected by
some criteria.
id ID
show the nexthop buckets that belong to a nexthop group with a given id
nhid ID
show the nexthop buckets that hold a nexthop with a given id
dev DEV
show the nexthop buckets using the given device
vrf NAME
show the nexthop buckets using devices associated with the vrf name
master DEV
show the nexthop buckets using devices enslaved to given master device
ip nexthop bucket get id ID index INDEX
get a single nexthop bucket by nexthop group id and bucket index
EXAMPLES
ip nexthop ls
Show all nexthop entries in the kernel.
ip nexthop add id 1 via 192.168.1.1 dev eth0
Adds an IPv4 nexthop with id 1 using the gateway 192.168.1.1 out device eth0.
ip nexthop add id 2 encap mpls 200/300 via 10.1.1.1 dev eth0
Adds an IPv4 nexthop with mpls encapsulation attributes attached to it.
ip nexthop add id 3 group 1/2
Adds a nexthop with id 3. The nexthop is a group using nexthops with ids 1 and 2 at
equal weight.
ip nexthop add id 4 group 1,5/2,11
Adds a nexthop with id 4. The nexthop is a group using nexthops with ids 1 and 2 with
nexthop 1 at weight 5 and nexthop 2 at weight 11.
ip nexthop add id 5 via 192.168.1.2 fdb
Adds a fdb nexthop with id 5.
ip nexthop add id 7 group 5/6 fdb
Adds a fdb nexthop group with id 7. A fdb nexthop group can only have fdb nexthops.
ip nexthop add id 10 group 1/2 type resilient buckets 32
Add a resilient nexthop group with id 10 and 32 nexthop buckets.
SEE ALSO
ip(8)
AUTHOR
Original Manpage by David Ahern <dsahern@kernel.org>