[j-nsp] Aggreagte Route Problem

From: Sher, Ryan (RSher@flagtelecom.com)
Date: Tue Jun 04 2002 - 14:46:24 EDT


Hi,

I am trying to announce some aggregate routes from the core of my network
(router: sfc1) to a router on the edge (router tok2). I dont understand the
results I have seen. I have a simple policy on the RR in the core (sfc1)
which takes the aggregate routes and advertises them to the clients on the
edge (tok2). This policy works fine.

The problem occurs on router tok2. It seems that out of two aggregates I
advertise only one gets installed in the routing table while the other is
hidden. I cant see any differences between these two aggregates, so it
doesn't make sense to me why one would be installed in the Routing Table and
the other not. The hidden route is telling me that the next hop is unusable,
however tok2 does have a default route to this next hop (and the route that
works has the identical next hop!)

If I put a static route to the next hop both aggregates start working ...
why?

Thanks
Ryan

Here are some outputs comparing the two routes:

lab@tok2# run show route 20.100.0.0/16 extensive hidden

inet.0: 41 destinations, 60 routes (38 active, 0 holddown, 3 hidden)
20.100.0.0/16 (1 entry, 0 announced)
         BGP Preference: 170/-101
                Next hop type: Unusable
                State: <Hidden Int Ext>
                Local AS: 15412 Peer AS: 15412
                Age: 14:22
                Task: BGP_15412.20.100.11.3+179
                AS path: IAggregator: 15412 20.100.11.3
                Communities: 15412:700
                Localpref: 100
                Router ID: 20.100.11.3
                Indirect nexthops: 1
                        Protocol Nexthop: 20.100.11.3 Indirect nexthop: 0 -

[edit]
lab@tok2# run show route 20.200.0.0/16 extensive

inet.0: 39 destinations, 57 routes (36 active, 0 holddown, 3 hidden)
20.200.0.0/16 (1 entry, 1 announced)
TSI:
KRT in-kernel 20.200.0.0/16 -> {indirect(69)}
Page 0 idx 1 Type 1 val 83c5e8c
    Nexthop: 20.100.11.3
    AS path: I
    Aggregator: 15412 20.100.11.3
    Communities: 15412:700
Path 20.200.0.0 from 20.100.11.3 Vector len 4. Val: 1
        *BGP Preference: 170/-101
                Source: 20.100.11.3
                Nexthop: via t3-0/1/0.0, selected
                Protocol Nexthop: 20.100.11.3 Indirect nexthop: 8469110 69
                State: <Active Int Ext>
                Local AS: 15412 Peer AS: 15412
                Age: 22:02 Metric2: 12
                Task: BGP_15412.20.100.11.3+179
                Announcement bits (3): 0-KRT 4-BGP.0.0.0.0+179 5-Resolve
inet.0
                AS path: IAggregator: 15412 20.100.11.3
                Communities: 15412:700
                Localpref: 100
                Router ID: 20.100.11.3
                Indirect nexthops: 1
                        Protocol Nexthop: 20.100.11.3 Metric: 12 Indirect
nexthop: 8469110 69
                        Indirect path forwarding nexthops: 1
                Nexthop: via t3-0/1/0.0

[edit]
lab@tok2# run show route 20.100/16

inet.0: 39 destinations, 57 routes (36 active, 0 holddown, 3 hidden)
+ = Active Route, - = Last Active, * = Both

20.100.16.1/32 *[Direct/0] 3d 04:13:05
> via lo0.0
20.100.16.2/32 *[OSPF/10] 00:00:28, metric 2
> via t3-0/1/1.0
20.100.50.0/30 *[Direct/0] 3d 03:17:43
> via t3-0/1/0.0
                    [OSPF/10] 00:00:33, metric 2
> via t3-0/1/0.0
20.100.50.2/32 *[Local/0] 3d 04:13:05
                      Local via t3-0/1/0.0
20.100.50.4/30 *[OSPF/10] 00:00:28, metric 4
> via t3-0/1/1.0
20.100.50.8/30 *[Direct/0] 00:00:33
> via t3-0/1/1.0
                    [OSPF/10] 00:00:28, metric 2
> via t3-0/1/1.0
20.100.50.9/32 *[Local/0] 00:00:33
                      Local via t3-0/1/1.0

[edit]
lab@tok2# run show route 20.200/16

inet.0: 39 destinations, 57 routes (36 active, 0 holddown, 3 hidden)
+ = Active Route, - = Last Active, * = Both

20.200.0.0/16 *[BGP/170] 00:20:11, localpref 100, from 20.100.11.3
                      AS path: I
> via t3-0/1/0.0
20.200.1.0/24 *[Direct/0] 3d 04:13:09
> via fe-0/0/0.100
20.200.1.1/32 *[Local/0] 3d 04:13:09
                      Local via fe-0/0/0.100
20.200.2.0/24 *[Direct/0] 3d 04:13:09
> via fe-0/0/0.200
20.200.2.1/32 *[Local/0] 3d 04:13:09
                      Local via fe-0/0/0.200

[edit]
lab@tok2# run show route 20.100.11.3

inet.0: 41 destinations, 60 routes (38 active, 0 holddown, 3 hidden)
+ = Active Route, - = Last Active, * = Both

0.0.0.0/0 *[OSPF/10] 00:01:25, metric 12
> via t3-0/1/0.0
                    

[edit]
lab@tok2# run ping 20.100.11.3
PING 20.100.11.3 (20.100.11.3): 56 data bytes
64 bytes from 20.100.11.3: icmp_seq=0 ttl=255 time=0.924 ms
64 bytes from 20.100.11.3: icmp_seq=1 ttl=255 time=0.848 ms
64 bytes from 20.100.11.3: icmp_seq=2 ttl=255 time=0.825 ms

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