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Community Member

GRE/IP tunnel with Cisco GSR 12008

We are trying to establish GRE/IP tunnel with Cisco GSR 12008 but are not able to do that. The config is simple:

interface Tunnel0

description GRE-tunnel0-1

ip address a.b.c.d

no ip directed-broadcast

load-interval 30

keepalive 10 3

tunnel source POS1/3

tunnel destination x.y.z.t


The POS1/3 interface is 4OC3 POS.

We are getting some logs like these:

000660: Nov 25 01:00:47: Tunnel0: GRE/IP encapsulated ->x.y.z.t(linktype=7, len=48)

000661: Nov 25 01:00:57: Tunnel0: sending keepalive, x.y.z.t-> ttl=255), counter=2

000662: Nov 25 01:00:57: Tunnel0: GRE/IP encapsulated>x.y.z.t(linktype=7, len=48)

000663: Nov 25 01:01:07: Tunnel0: sending keepalive,>x.y.z.t(len=24 ttl=255), counter=3

000664: Nov 25 01:01:07: Tunnel0: GRE/IP encapsulated>x.y.z.t(linktype=7, len=48)

000665: Nov 25 01:01:17: Tunnel0: sending keepalive, x.y.z.t-> ttl=255), counter=4

000666: Nov 25 01:01:17: Tunnel0: GRE/IP encapsulated>x.y.z.t(linktype=7, len=48),

where is the IP address of POS1/3.

What are we doing wrong?

Thanks in advance,


Hall of Fame Super Gold

Re: GRE/IP tunnel with Cisco GSR 12008


Based on what you have posted, I am not convinced that you have done anything wrong. I see in your config that you have enabled GRE tunnel keepalives (which is a fairly new feature in IOS). You configuration specifies to send a keepalive every 10 seconds. The debug seems to be showing that every 10 seconds there is an exchange of keepalive messages between the two ends of the tunnel. It looks to me like it is working as expected.If you think that something is not right, can you help explain the symptoms?



Community Member

Re: GRE/IP tunnel with Cisco GSR 12008

The problem is that the line protocol of Tunnel interface of GSR is down. We bought an 16OC3/POS interface, that has Engine 2, which, based on supports GRE tunneling on customer-facing interfaces.

Still we have the same results, interface up, line protocol down.

One other problem is that on command:

hw-module slot 3 mode server, the router replies with: Cannot configure - wrong card type for a server card.

The strange thing is that line protocol goes us when we use tunnel mode dvmrp.

Any help appreciated,


Hall of Fame Super Gold

Re: GRE/IP tunnel with Cisco GSR 12008


You are dealing with hardware with which I have no experience and no real expertise. If it is a problem with hardware or of feature support for that hardware in your particular IOS I will not be much help.

The error message you report when you try to enable server mode and the fact that it works for DVMRP do seem to point to it being an issue with support for the GRE feature on this hardware in the particular version of IOS that you are using. Have you checked for any known bugs in your version of software related to support for GRE?

If this router is covered by a maintenance contract I would suggest that opening a case with the TAC would be the most direct way to get it resolved.



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