ISDN backup stay connected

[fisko]

Hello! I have 3 routers. 2 of them are connected over frame relay and third router is used for backup. All 3 using eigrp and backup router is using static floating route to make backup. The problem is that ISDN stay connected when frame relay become up.

[fisko]

If I put the bandwidth 40 will this decrease speed on logical level.....on ISDN? Or is it a just used for best route calculation?

[kerek]

The bandwidth and delay configuration only affects the routing protocol metric calculation and does not affect the physical behaviour of the link.

[fisko]

Here is the EIGRP topology and neigbors after all link are up

BACKUP ROUTER

EIGRP Neighbour

D 172.20.91.0 [90/40514560] via 172.30.30.2, (this is ISDN IP)

EIGRP Topology

P 172.20.91.0/24, 1 successors, FD is 40514560

via 172.30.30.2 (40514560/28160), BRI2/7

FRAME RELAY ROUTER

EIGRP NEighbor (It puts ISDN router in eigrp table not serial link)

D 172.20.91.0 [90/40517120] via 172.30.100.3, 00:02:57, FastEthernet1

EIGRP Topology

P 172.20.91.0/24, 1 successors, FD is 40517120

via 172.30.100.3 (40517120/40514560), FastEthernet1 (This is eigrp route over ISDN ROUTER )

via 172.30.160.2 (297246976/28160), Tunnel1

(This is EIGRP route over frame relay that is encapsulated in GRE)

What to configure on ISDN BACKUP router and Frame relay router in order to get

172.30.160.2 (297246976/28160), Tunnel1

As primary EIGRP route....

It seems that tunnel traffic have a big delay so ISDN is brinnging up and say up

[kerek]

You didn't mentioned so far there is a GRE tunnel through the FR link.

In this case eigrp will calculate the metric based on the bandwidth and delay of the tunnel interface.

Let's set the bandwidth under tunnel interface to much higher than on bri. What's the cir of the FR link? Anyway why do you use GRE over FR? It just introduce additional overhead.

[fisko]

It is little complicated......this is not real point to point frame relay........I must have VPN for solution and also want to use EIGRP as my routing protocol in topology.....so i encapsulate EIGRP in GRE.... CIR is 512 Kbps

[fisko]

I have also few same EIGRP....GRE...ISDN static floating combinations and they working fine....just this one making a problem....

[kerek]

So the problem is with GRE is that its default bandwidth is 9kbit/s and the delay is also very high.

For instance:

Tunnel0 is up, line protocol is down

Hardware is Tunnel

MTU 1514 bytes, BW 9 Kbit, DLY 500000 usec,

So let's change it to 512 and if needed reduce the delay here or increase the delay on bri.

You will see how the FD changed on the ROUTER using the show ip topology.

You have to alter these values until the route table will be changed.

Another solution is to use eigrp offset list to anounce the remote LAN prefix with much higher delay but now try the above.

[fisko]

THANKS A LOT! Give You the feedback!

[fisko]

It seems that is working. After I put bandwidth to Tunnel interface ISDN stay down....THANKS AGAIN!

[kerek]

Happy to help.