[j-nsp] ipip and gre interfaces

[Jesper Skriver]

On Sun, Nov 24, 2002 at 04:49:42PM +0100, Blaz Zupan wrote:
> I have two upstream STM-1's to two different upstream ISP's connected to two
> M5's located in different POPs and two local E3's connecting the M5's. I'd
> like to somehow backup the E3's in case they fail (they are going through the
> same telco). I thought I'd build a tunnel between the two STM-1's in case the
> E3 fails. I don't have a tunnel PIC in any of my M5's and don't want to get on
> just to build this tunnel (it would probably be cheaper to move one of the
> E3's to another telco and get redundancy this way, which is what I'll
> probably eventually do).
> 
> What is the usefulness of the ipip and gre interfaces (not the gr-x/x/x and
> ip-x/x/x interfaces you get when you have a tunnel PIC)? I successfuly built a
> tunnel between the M5's with the ipip interface and can ping the other side
> through the tunnel, but trying to route through the tunnel I get a network
> unreachable for every packet. Configuration was something like
> 
> interfaces {
>   ipip {
>     unit 0 {
>       tunnel {
>         source 192.168.1.1;
>         destination 192.168.2.1;
>       }
>       family inet {
>         address x.x.x.x/30;
>       }
>     }
>   }
> }
> 
> ... and the opposite on the other side.
> 
> Is the usage of those ipip and gre interfaces documented anywhere? I wasn't
> able to find any documentation on them.
> 
> Any help will be appreciated.

My experience is that gre is only usefull for routing-engine sourced
traffic, just as the fxp0 interface is.

So it cannot be used for user traffic.

/Jesper

-- 
Jesper Skriver, jesper(at)skriver(dot)dk  -  CCIE #5456
Senior network engineer @ AS3292, TDC Tele Danmark

One Unix to rule them all, One Resolver to find them,
One IP to bring them all and in the zone to bind them.