Subject: (ngtrans) Red Templin's Comment on Shipworm

From: "Michael Cole" <[email-masked]>
Date: Thu, 26 Sep 2002 1:42:58 -0400

Hello,

Actually I think that the Shipworm prefix could be shortened to 16 bits. I 
we eliminate the need for an EUI-64 format as I suggested elsewhere, we would 
have even more bits with which to play around. I also wondered why an address 
needed to be obfuscated. Now I know.

The suggestion that I made was a serious ripoff of RFC 3056, Isatap, and 
Shipworm concepts. Here is the global address format:

    0    1   
1                       4   
4   6  6    7 
7           7  
8        9   
9         12

    0    
5   6                       
7   8   3  4    1 
2           9  
0        5   
6           7 

    1001 : GLOBALv4addr : SLA : Type, Behavior : Port#2 : 
v4addr#2

In the case of say a cable ISP that is stuck with using a NAT box and 
assigning RFC 1918 addresses to their subscribers they would be able to use the 
following setup:

4bone                                                                                         
6bone

|                                                                                                  |

9.0.0.1                                                                       
1001 : 9.0.0.1 ::/48

  ISP NAT 
box(es)                                                       2002 
: 9.0.0.1 ::/48

      |  
192.168.253.Z                                                                          
|

|                                                                                                   |

   4router-----------Shipworm+Isatap 
Server(s)------------------6router

|                       
192.168.250.Z                                                    |

|                       
1001 : 9.0.0.1 : 2300 :: 
/56                                |

IPv4 
subscribers                                                                  IPv6 
customers

In this case, the Shipworm+Isatap servers would be connected ahead of the 
Point of Presence NAT so as to take load off of it. The Site Level 
Aggregator would be used by the 6router to differentiate between the Shipworm 
servers and the customers who have native IPv6 connectivity. The Shipworm+Isatap 
servers could be implemented in such a way as to not really care if 
the IPv4 subscriber is using a NAT - the extra features would not be used. I 
also included the RFC 3056 prefix in this scheme so that native Ipv6 customers 
can use it.

The GLOBALv4addr makes the addresses unique. The Port number and the 
v4addr#2 would be the subscriber's RFC 1918 address and port number for a 
particular connection.

I suspect that having a device Type field would be a good idea as there are 
probably some devices that engage in NAT-like behavior. Examples would be 
encryption boxes and the like and to upgrade we would need some type of Shipworm 
or similar box at each end. The Behavior field would correspond to Mr. Huitema's 
flags field.

There would also be a site-local format:

    1002 : optionalv4addr#1 : SLA : Type, Behavior : Port #2 
:v4addr#2

If you do not need the optional v4addr#1, zero it out.

Same goes for link local:

   1004 : v4addr#1 : Port#1 : Type, Behavior : Port#2 : v4addr#2 
If you do not need v4addr#1 or Port#1, zero them out.

A node local format would be useful when the Shipworm server is 
running on the same CPU as a NAT box:

   1006 : v4addr#1 : Port#1 : Type, Behavior : Port#2 : 
v4addr#2 If you do not need v4 addr#1 or Port#1, zero them out.

In this scheme, global addresses would have an odd prefix and local 
addresses would have an even prefix. The object is to make Shipworm as flexible 
as possible.

--- Michael Cole

--- [email-masked] 

--- EarthLink: It's your Internet.