Subject: Re:

From: "aridaman kaushik" <[email-masked]>
Date: 12 Dec 2002 08:56:46 -0000

Hi all,
    I have a doubt regarding ipv6 over ipv4 tunnel.

1. When a tunnel is configured, source and destination is 
configured.
Is it sufficient to configure destination address only. My means 
to say why source address is required.

2. Is it necessary to establish path between source and 
destination before configuring tunnel and use this path in routing 
header of tunneled packet for forwarding the packet.

3. I have one more doubt, when there is concept of fast path and 
slow path, which functionality of the tunnelling should go to the 
fast path and which functionality of tunnelling should go to the 
slow path.

thanks in advance

regards
ari.

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From: Mukesh Gupta <[email-masked]>
Date: Fri, 13 Dec 2002 07:42:46 -0800

Hi Ari,

>     I have a doubt regarding ipv6 over ipv4 tunnel.

I think your questions are pretty generic to any IPinIP tunnels.

> to say why source address is required.

You need to put these source and destination addresses in the tunnel
header of the packet. The source address is required so that the router
at the other end of the tunnel can send the packets back to the router
who tunnelled the packet.

> header of tunneled packet for forwarding the packet.

I don't think that's necessary. You could just tunnel the packet and
forward it as a normal IP packet. The tunnelled packet has the outer IP
header (tunnel IP header) which is sufficient to forward the packet
throughout the path.

> fast path and which functionality of tunnelling should go to the

I think, the tunnel processing (encapsulating the packet in another IP
header) should be done in slow path.

regards
Mukesh