Auto-Tunnel Primary and Backup with CBTS

Unanswered Question
Nov 26th, 2008

Hi, recently been spending quite some times on figuring out a solution that can meet customer's requirement and ease the configuration maintenance in the future.


1. Must have @ least link or node protection aka FRR (so that put LDP signalled LSP out of the question)

2. Only selected traffic among few sites will be routed through explicit path, rest of the traffic follow IGP, that narrow down into CBTS

So I'll have all sites enabled with Auto-tunnel primary and backup of NH and NNH. This works fine, for the selected site that have specific application to routed via an explicit path, i created two manual tunnels, with one tunnel match EXP5 and EXP6, and the other tunnel matching default.

With this configuration, i suppose the end-result is like these:

1. Site without no manually created tunnel will follow the auto-tunnel created dynamically

2. Between sites with the manual tunnel, EXP5 and EXP6 goes into first tunnel without explicit path, rest of the traffic between these sites will get routed into the 2nd manual tunnel which match EXP default. There's no traffics between these sites (with manual tunnels) will get routed into the Auto-Tunnel

Is this workable, I've attached 2 PE configuration, once I enable the manual tunnels (CBTS), one of the PE still have the Auto-Tunnels up and FRR enabled, the other PE have lost the FRR capability, and with only 1 primary auto-tunnel active.

My questions go like this:

1. If there's a scenario where sites without manual tunnel has traffic flow to the site with manual tunnel, the sites with manual tunnels will reply the traffic via the auto-tunnel or the 2nd manual tunnel which match to default EXP? Or it'll smart enough to reply those sites with pure auto-tunnels with its own auto-tunnel?

Hope I dun get the question mess up.

Thanks and have a good day! Its 3 in the morning here..sigh

I have this problem too.
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networknoobs Wed, 11/26/2008 - 11:18

Here's both PE config attached, notice that the R3 has all the auto-tunnel up and with FRR running fine, and that's not the case with R4.

If i delete both "int tunnel 1 and 2", both R3 and R4 will have total of 4 auto-tunnels up and with FRR enabled.

Any ideas?

networknoobs Mon, 12/01/2008 - 07:25

I've tried to building a proper physically full-meshed P router and has PE connected into the P cloud.

With AutoTunnel primary and backup it works flawlessly, then I introduce a manual tunnels which configured to route particular type of traffics over the explicit path, I face 2 issues:

1. If the manual tunnels is up, all traffics goes into the manual tunnel although the tunnel just match a specific EXP value

2. If i take away the manual tunnel "autoroute announce" config, then everything goes through the Auto-Tunnel.

Looking at this, is there a possible way I can force the specific traffic to utilize manual tunnels, while the rest of the traffics going through the AutoTunnel?

I tried to avoid the manual tunnel to participate into the IGP SPF by take away the "autoroute announce", then in each of the PE router I perform a specific destination route in the specific vrf via the manual tunnel, but still, the ping does not want to go through...

Would really appreciate ideas here, thanks a million

Giuseppe Larosa Mon, 12/01/2008 - 13:48

Hello Creed,

if the traffic you want to put on the tunnel belongs to an MPLS L3 VPN you just need a static route on the global routing table for the BGP next-hop you see on the VRF routing table as

B [200/x] remote subnet via remote-PE-loopback

ip route remote-PE-loopback tunnel

for recursion the traffic of the MPLS L3 VPN will be forwarded over the tunnel

Hope to help



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