# ip-nexthop

## 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_ [ **hw_stats**{ **on** | **off**}  ] [
                   **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.
    


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