[j-nsp] Forwarding Table Entries represented with ">"

[Jonathan Looney]

Barry,

This is standard behavior.  Enabling multipath only causes the router to
install multiple next-hops to a destination in the routing table.  As the
documentation indicates, the router will choose a single next hop to install
in the forwarding table and it marks this next hop with a carat (>).

If you use a forwarding table policy to cause the router to install multiple
next hops (as your output below indicates you have done), the router will do
so, but it will still indicate with a carat the single next-hop it would use
absent the forwarding table policy modification.

-Jon

On 6/5/07, Barry O'Connell <Barry.O'Connell at irishbroadband.ie> wrote:
>
> I am trying to figure out the significance of the ">" symbol within the
> routing table output on the Juniper routers.
>
> According to juniper docs:
> "Next hop information Routes may be assigned more than one next-hop
> value. Each next hop instructs the router where to forward packets for
> each route. When multiple next hops exist, the routing table selects a
> single next hop to be placed in the forwarding table. This selected next
> hop is marked with a caret (>) in the output. Multiple next-hop values
> can be placed in the forwarding table. "
>
> I have sample output from one of our routers, with BGP multipath
> running.
> Both routes learned to dest are provided as next hops to the active
> route & both are installed in the forwarding table.
>
> Yet only one of the routes is represented with a ">" in the show route
> output.
>
> Any thoughts would be appreciated.
>
> user at SITEA> show route 8.6.80.0/23
>
> inet.0: 221846 destinations, 407889 routes (221845 active, 0 holddown, 1
> hidden)
> + = Active Route, - = Last Active, * = Both
>
> 8.6.80.0/23        *[BGP/170] 3d 00:12:51, MED 0, localpref 100, from
> ip.ip.ip.ip
>                       AS path: 3356 11186 I
>                       to x.x.x.x via ge-0/0/0.208, label-switched-path
> gate-1
>                     > to y.y.y.y via ge-0/0/0.209, label-switched-path
> gate-2
>                     [BGP/170] 3d 00:12:44, MED 0, localpref 100, from
> ip.ip.ip.ip
>                       AS path: 3356 11186 I
>        > to y.y.y.y via ge-0/0/0.209, label-switched-path gate-1
>
>
> user at SITEA> show route forwarding-table destination 8.6.80.0/23 detail
> Routing table: inet
> Internet:
> Destination        Type RtRef Next hop           Type Index NhRef Netif
> 8.6.80.0/23        user     0                    ulst 262153 167465
>                                                  indr 262147 34304
>                               x.x.x.x     Push 364400       ge-0/0/0.208
>                                                  indr 262145 15499
>                               y.y.y.y     Push 336544       ge-0/0/0.209
>
> user at SITEA> show route forwarding-table destination 8.6.80.0/23
> extensive Routing table: inet [Index 0]
> Internet:
>
> Destination:  8.6.80.0/23
>   Route type: user
>   Route reference: 0                   Route interface-index: 0
>   Flags: sent to PFE
>   Next-hop type: unilist               Index: 262153   Reference: 167465
>   Next-hop type: indirect              Index: 262147   Reference: 34304
>   Nexthop: x.x.x.x
>   Next-hop type: Push 364400
>   Next-hop interface: ge-0/0/0.208
>   Next-hop type: indirect              Index: 262145   Reference: 15499
>   Nexthop: y.y.y.y
>   Next-hop type: Push 336544
>   Next-hop interface: ge-0/0/0.209
>
>
>
> Barry O'Connell
> IP Engineering Manager
>
> Irish Broadband
> Unit 6, Sandyford Business Centre
> Sandyford Industrial Estate
> Dublin, Dublin 18
> Republic of Ireland
>
> Mobile:
> Email: barry.oconnell at irishbroadband.ie
>
>
>
>
>
>
>
>
>
>
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