From: Matt Holbert (mholbert@xxxxxxxxxxx)
Date: Thu Jul 06 2000 - 14:59:32 GMT-3
Thanks to John Galt Kupec for pointing me in the direction for a solution.
The answer given by CCIEbootcamp does NOT work. The real solution is to
enter two routes as such:
decnet route default 1.6
decnet route 1.6 bri 0 2 3<--Make this route a floating static
The default route points to 1.6. The router then uses recursive lookup that
points to bri 0 by the floating static route.
Thanks to all who helped or took the time to read...
> -----Original Message-----
> From: Matt Holbert [mailto:mholbert@icscorp.com]
> Sent: Thursday, July 06, 2000 11:14 AM
> To: ccielab@groupstudy.com
> Subject: RE: DECNET over ISDN
>
>
>
> Some of you have sent me snippets of the CCIEbootcamp lab8
> configuration.
> Lab8 is what got me first thinking about this. The Lab8
> DECNET over ISDN
> configuration does NOT work from what I can tell. The BGP keepalives
> between R1 and R6 keeps the ISDN up periodically, just enough to allow
> periodic refreshes of the DECNET routing tables. Try it
> simply router to
> router. IT DOES NOT WORK!
>
> Let me go into detail why. I am on node 1.7, trying to
> decnet ping node
> 1.6. Assume we have a default route like such:
>
> decnet route default 1.6 1 3
>
> This tells the router to route all routes not in the table to
> 1.6. However,
> if you look in the routing table, 1.6 is not specified.
> Because no route is
> available, routing fails as depicted below.
>
> R7#sh decnet route
> Area Cost Hops Next Hop to Node Expires Prio
> *1 0 0 (Local) -> 1.7
> Node Cost Hops Next Hop to Node Expires Prio
> *(Area) 0 0 (Local) -> 1.7
> *1.7 0 0 (Local) -> 1.7
>
> *DEFAULT* : 3 1 using next hop address of 1.6
>
> R7#ping decnet 1.6
>
> Type escape sequence to abort.
> Sending 5, 100-byte DECnet echos to 1.6, timeout is 5 seconds:
>
> Host unreachable+
> Host unreachable+
> Host unreachable+
> Host unreachable+
> Host unreachable+
> Success rate is 0 percent (0/5)
> R7#
>
> If we change the default route to the interface instead of
> the address,
> encapsulation fails as detailed below.
>
> R7#sh decnet route
> Area Cost Hops Next Hop to Node Expires Prio
> *1 0 0 (Local) -> 1.7
> Node Cost Hops Next Hop to Node Expires Prio
> *(Area) 0 0 (Local) -> 1.7
> *1.7 0 0 (Local) -> 1.7
>
> *DEFAULT* : 3 1 out on interface BRI0,
>
> R7#debug decnet events
> DECnet packets (errors) debugging is on
> R7#ping decnet 1.6
> 13:22:40: DNET: Encapsulation failed (3) for interface BRI0
> 13:22:40: DNET: Encapsulation failed (3) for interface BRI0
>
> Type escape sequence to abort.
> Sending 5, 100-byte DECnet echos to 1.6, timeout is 5 seconds:
>
> 13:22:42: DNET: BRI0 Discard packet, waiting for re-enable.
> 13:22:47: DNET: BRI0 Discard packet, waiting for re-enable.
> 13:22:52: DNET: BRI0 Discard packet, waiting for re-enable
> 13:22:54: DNET: Sending level 2 routing updates on interface Ethernet1
> 13:22:54: DNET: Sending level 2 routing updates on interface Serial1
> 13:22:54: DNET: Sending level 2 routing updates on interface BRI0
> 13:22:54: DNET: Encapsulation failed (4) for interface BRI0
> 13:22:55: DNET: Encapsulation failed (3) for interface BRI0
> 13:22:55: DNET: Encapsulation failed (3) for interface BRI0.
> 13:22:57: DNET: BRI0 Discard packet, waiting for re-enable.
> 13:23:02: DNET: BRI0 Discard packet, waiting for re-enable.
> Success rate is 0 percent (0/5)
> R7#
> 13:23:10: DNET: Encapsulation failed (3) for interface BRI0
>
> If I bring up the line with another protocol, say IP, the
> pings are answered
> as detailed below.
>
> R7#sh decnet route
> Area Cost Hops Next Hop to Node Expires Prio
> *1 0 0 (Local) -> 1.7
> Node Cost Hops Next Hop to Node Expires Prio
> *(Area) 0 0 (Local) -> 1.7
> *1.6 2 1 BRI0 -> 1.6
> 40 64 V
> *1.7 0 0 (Local) -> 1.7
> *1.8 3 2 BRI0 -> 1.6
>
> *DEFAULT* : 3 1 out on interface BRI0,
>
> R7#ping decnet 1.6
>
> Type escape sequence to abort.
> Sending 5, 100-byte DECnet echos to 1.6, timeout is 5 seconds:
> !!!!!
> Success rate is 100 percent (5/5), round-trip min/avg/max =
> 20/23/24 ms
> R7#
>
> This works because the decnet routing tables are refreshed
> when the ISDN
> line comes up. Now the BRI is mapped to node 1.7. After the ISDN call
> terminates and the DECNET routes timeout, the pings quit working.
>
> Does anyone have any workarounds?
> Matt
>
> > -----Original Message-----
> > From: Matt Holbert [mailto:mholbert@icscorp.com]
> > Sent: Wednesday, July 05, 2000 5:41 PM
> > To: CCIE Lab (E-mail)
> > Subject: DECNET over ISDN
> >
> >
> >
> > Hey everybody,
> >
> > I am working on DECNET over ISDN. I have a serial connection
> > between two
> > routers and I want the ISDN to be used if the serial fails.
> > My interesting
> > traffic for the BRI is DECNET only, not DECNET routing. The
> > problem is when
> > the serial goes down. If IP activates the ISDN, the DECNET
> > routes enter the
> > routing table. However, when the BRI closes the routes age
> out of the
> > routing table.
> >
> > R1---------Serial-------------R2
> > \ /
> > \ /
> > \ /
> > \------ISDN-------/
> >
> >
> > My solution was a DECNET default route. However, if I use
> the distant
> > DECNET address as the destination, the routing fails because
> > the recursive
> > lookup for the distance route has aged out. If I use the
> > interface as the
> > destination, the encapsulation fails because the dialer map
> > uses the distant
> > address.
> >
> > Anyone have a solution?
> >
> > Thanks,
> > Matt Holbert
> > Network Engineer
> > Integrated Communication Solutions, Inc.
> > mholbert@icscorp.com
> > http://www.icscorp.com
> >
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