[j-nsp] can i see bgp looped AS PATH prefixes on the receiving router

Shamen Snyder shamen.snyder at gmail.com
Fri Jun 16 18:31:18 EDT 2017


Originally you did need bgp keep all to see routes that failed as-path loop
checks. I thought that changed in one of the version releases however, that
doesn't appear to be the case. Its the same on eBGP and cBGP. You need keep
all to see it.

I did this from 12.1.


root at mpr0.rdu.lab# run show route hidden extensive

inet.0: 17 destinations, 19 routes (17 active, 0 holddown, 2 hidden)
1.1.1.0/24 (3 entries, 1 announced)
TSI:
KRT in-kernel 1.1.1.0/24 -> {}
Page 0 idx 0 Type 1 val 9365148
    Nexthop: Self
    Localpref: 100
    AS path: [65000] I
    Communities:
Path 1.1.1.0 Vector len 4.  Val: 0
         BGP
                Next hop type: Unusable
                Address: 0x8f28f64
                Next-hop reference count: 4
                State: <Hidden Int Ext>
                Inactive reason: Unusable path
                Local AS: 65000 Peer AS: 65002
                Age: 1:00
                Task: BGP_65002.10.10.10.5+179
                AS path: (65002 65000) I (Looped: 65000)
                Router ID: 10.0.0.2
                Indirect next hops: 1
                        Protocol next hop: 10.10.10.4
                        Indirect next hop: 0 -
                        Indirect path forwarding next hops: 0
                                Next hop type: Unusable




On Fri, Jun 16, 2017 at 3:04 PM, Aaron Gould <aaron1 at gvtc.com> wrote:

> I wonder if confederations are creating the difference with what y’all are
> expecting to see ?  In other words, perhaps confederations don’t show loop
> AS’s as hidden.  Just guessing as I learn…
>
>
>
> Here’s both sides, of what is sent from r5 and what is received on r4 ?
>
>
>
> [edit]
>
> r4 at lab-mx104:r4# show protocols bgp group my-cbgp | display set
>
> set logical-systems r4 protocols bgp group my-cbgp type external
>
> set logical-systems r4 protocols bgp group my-cbgp traceoptions file r4-cgp
>
> set logical-systems r4 protocols bgp group my-cbgp traceoptions flag state
> detail
>
> set logical-systems r4 protocols bgp group my-cbgp traceoptions flag route
> detail
>
> set logical-systems r4 protocols bgp group my-cbgp traceoptions flag
> update detail
>
> set logical-systems r4 protocols bgp group my-cbgp export my-ibgp
>
> set logical-systems r4 protocols bgp group my-cbgp neighbor 10.0.2.9
> peer-as 65001
>
>
>
> [edit]
>
> r4 at lab-mx104:r4# run show route receive-protocol bgp 10.0.2.9
>
>
>
> inet.0: 35 destinations, 39 routes (35 active, 0 holddown, 0 hidden)
>
>   Prefix                  Nexthop              MED     Lclpref    AS path
>
> * 192.168.50.0/24         10.0.2.9                     100        (65001)
> I
>
>   192.168.60.0/24         10.0.9.6                     100        (65001)
> I
>
>   192.168.70.0/24         10.0.9.7                     100        (65001)
> I
>
>
>
> [edit]
>
>
>
>
>
>
>
> [edit]
>
> r5 at lab-mx104:r5# show protocols bgp group my-cbgp | display set
>
> set logical-systems r5 protocols bgp group my-cbgp type external
>
> set logical-systems r5 protocols bgp group my-cbgp export my-ibgp
>
> set logical-systems r5 protocols bgp group my-cbgp neighbor 10.0.2.2
> peer-as 65000
>
> set logical-systems r5 protocols bgp group my-cbgp neighbor 10.0.2.10
> peer-as 65000
>
>
>
> [edit]
>
> r5 at lab-mx104:r5# run show route advertising-protocol bgp 10.0.2.10
>
>
>
> inet.0: 38 destinations, 43 routes (38 active, 0 holddown, 0 hidden)
>
>   Prefix                  Nexthop              MED     Lclpref    AS path
>
> * 192.168.10.0/24         10.0.6.1                     101        (65000)
> I
>
> * 192.168.20.0/24         10.0.6.2                     100        (65000)
> I
>
> * 192.168.30.0/24         10.0.2.2                     100        (65000)
> I
>
> * 192.168.50.0/24         Self                         100        I
>
> * 192.168.60.0/24         10.0.9.6                     100        I
>
> * 192.168.70.0/24         10.0.9.7                     100        I
>
> * 192.168.100.0/24        10.0.6.1                     101        (65000)
> I
>
>
>
>
>


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