[j-nsp] JNCIP EBGP Case Study...

ta hong quang tahongquang at gmail.com
Thu Oct 29 05:41:45 EDT 2009


Hi Hoogen

>> lab at R3# run show route receive-protocol bgp 10.0.6.1
>>
>> inet.0: 66 destinations, 106 routes (63 active, 0 holddown, 17 hidden)
>>   Prefix                  Nexthop              MED     Lclpref    AS path
>> * 192.168.10.0/24         10.0.6.1                     100        I
>> * 192.168.100.0/24        10.0.6.1             101     101        I

In R3, you can see there are 17 hidden routes. You should to use the command
"run show route receive-protocol bgp 10.0.6.1 hidden detail" (i don't
remember exactly) to know why they are hidden?


On Thu, Oct 29, 2009 at 3:50 PM, Hoogen <hoogen82 at gmail.com> wrote:

> Hi Sean,
>
> Thank you for the reply...
>
> lab at R3# run show route 10.0.5.254
>
> inet.0: 66 destinations, 85 routes (63 active, 0 holddown, 3 hidden)
> + = Active Route, - = Last Active, * = Both
>
> 10.0.5.0/24        *[IS-IS/15] 00:23:12, metric 106
>                    > to 10.0.4.14 via ge-0/0/1.200
>                      to 10.0.4.2 via ge-0/0/2.0
>
> [edit]
> lab at R3#
>
> The Link between P1-R1 is being advertised by the IGP.. So next-hop self
> isn't required for this peer. I would assume if the nex-hop is a problem..
> the route would be hidden and set to Unusuable.. But this is not the
> case...
> I just don't seem to receive the route.
>
> -Hoogen
>
> On Thu, Oct 29, 2009 at 1:43 AM, Sean Clarke <sean at clarke-3.demon.nl>
> wrote:
>
> >
> > Are you doing "Next hop self" on R1 to advertise to R3, or are you trying
> > to send the routes without R3 knowing anything about the eBGP next-hop
> > 10.0.5.254 ?  If the latter, advertise the link between R1 and P1
> passively
> > towards R3
> >
> >
> >
> > On 10/29/09 9:27 AM, Hoogen wrote:
> >
> >> Well I am working with my J-Series routers to do most topologies.. This
> >> problem has somehow baffled me alot. Any help is greatly appreciated...
> >>
> >> A part of topology.. I think the problem lies somewhere in this...
> >>
> >> P1---R1---R3 (Both R1 and R3 are in 65000... and R1 is peering with P1
> >> which
> >> is AS 1492)
> >>
> >> R1 receives
> >>
> >> lab at R1# run show route receive-protocol bgp 10.0.5.254
> >>
> >> inet.0: 65 destinations, 69 routes (63 active, 0 holddown, 4 hidden)
> >>   Prefix                  Nexthop              MED     Lclpref    AS
> path
> >> * 3.4.0.0/20              10.0.5.254                              1492
> I
> >> * 6.0.0.0/7               10.0.5.254                              1492
> I
> >> * 120.120.0.0/24          10.0.5.254                              1492
> I
> >> * 120.120.1.0/24          10.0.5.254                              1492
> I
> >> * 120.120.2.0/24          10.0.5.254                              1492
> I
> >> * 120.120.3.0/24          10.0.5.254                              1492
> I
> >> * 120.120.4.0/24          10.0.5.254                              1492
> I
> >> * 120.120.5.0/24          10.0.5.254                              1492
> I
> >> * 120.120.6.0/24          10.0.5.254                              1492
> I
> >> * 120.120.7.0/24          10.0.5.254                              1492
> I
> >> * 120.120.69.128/25       10.0.5.254                              1492
> I
> >>
> >> __juniper_private1__.inet.0: 2 destinations, 2 routes (2 active, 0
> >> holddown,
> >> 0 hidden)
> >>
> >> iso.0: 1 destinations, 1 routes (1 active, 0 holddown, 0 hidden)
> >>
> >> [edit]
> >> lab at R1#
> >>
> >> And then R1 sends this to R3
> >>
> >> lab at R1# run show route advertising-protocol bgp 10.0.3.3
> >>
> >> inet.0: 65 destinations, 69 routes (63 active, 0 holddown, 4 hidden)
> >>   Prefix                  Nexthop              MED     Lclpref    AS
> path
> >> * 3.4.0.0/20              10.0.5.254                   100        65412
> >> 65412 1492 I
> >> * 6.0.0.0/7               10.0.5.254                   100        65412
> >> 65412 1492 I
> >> * 120.120.0.0/24          10.0.5.254                   100        65412
> >> 65412 1492 I
> >> * 120.120.1.0/24          10.0.5.254                   100        65412
> >> 65412 1492 I
> >> * 120.120.2.0/24          10.0.5.254                   100        65412
> >> 65412 1492 I
> >> * 120.120.3.0/24          10.0.5.254                   100        65412
> >> 65412 1492 I
> >> * 120.120.4.0/24          10.0.5.254                   100        65412
> >> 65412 1492 I
> >> * 120.120.5.0/24          10.0.5.254                   100        65412
> >> 65412 1492 I
> >> * 120.120.6.0/24          10.0.5.254                   100        65412
> >> 65412 1492 I
> >> * 120.120.7.0/24          10.0.5.254                   100        65412
> >> 65412 1492 I
> >> * 120.120.69.128/25       10.0.5.254                   100        65412
> >> 65412 1492 I
> >> * 192.168.10.0/24         Self                         100        I
> >> * 192.168.100.0/24        Self                 101     101        I
> >>
> >> [edit]
> >> lab at R1#
> >>
> >> So far so good...
> >>
> >> Now R3 only receives
> >>
> >> lab at R3# run show route receive-protocol bgp 10.0.6.1
> >>
> >> inet.0: 66 destinations, 106 routes (63 active, 0 holddown, 17 hidden)
> >>   Prefix                  Nexthop              MED     Lclpref    AS
> path
> >> * 192.168.10.0/24         10.0.6.1                     100        I
> >> * 192.168.100.0/24        10.0.6.1             101     101        I
> >>
> >> __juniper_private1__.inet.0: 2 destinations, 2 routes (2 active, 0
> >> holddown,
> >> 0 hidden)
> >>
> >> iso.0: 1 destinations, 1 routes (1 active, 0 holddown, 0 hidden)
> >>
> >> [edit]
> >> lab at R3#
> >>
> >> I check to see if I have an import policy but it's not present... I am
> not
> >> sure why I am not receiving any routes from R1 except for those internal
> >> routes...
> >>
> >> group 65000 {
> >>     type internal;
> >>     local-address 10.0.3.3;
> >>     export ibgp;
> >>     neighbor 10.0.6.1;
> >> }
> >>
> >> As you notice there is no policy to deny any routes.. Can someone help
> me
> >> out here..
> >>
> >> -Hoogen
> >> _______________________________________________
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> >>
> >>
> >>
> >>
> >
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