nanog mailing list archives
Re: IPv6 news
From: Michael.Dillon () btradianz com
Date: Mon, 17 Oct 2005 14:17:43 +0100
Is VJ compression considered a violation of the "end-to-end" principle?
VJ compression happens in the middle of the network, between two routers/gateways. End-to-end refers to the hosts, i.e. the computers which "host" the end users' applications. Of course, in the old days, many of these "hosts" also carried out the function of a gateway using a dialup modem, but that is still not violating the end-to-end model because the end user application never knows about the VJ compression. NAT is different because it causes some end-user applications to fail entirely. For instance an application which sends its IP address to another host with the instructions "call me back when something interesting happens". The NAT box in the middle causes the callback to fail in most cases. And end-to-end multihoming solution that is consistent with the end-to-end model will allow any application to communicate with another host even when one of the hosts moves to a different network location. BGP multihoming achieves this by announcing the small number of possible locations where a particular netblock can be found. The telephone system solves this by providing a central directory service where the network looks up an 800 number (or any portable number) to find the current location of the destination. Some people have used DNS techniques to do a similar sort of IPv4 multihoming, notably Paul Vixie and an Israeli box vendor whose name escapes me at the moment. Theoretically, in a network, a router/gateway could have some intelligence/state so that it does not simply forward packets based on destination addresses in the routing table. Instead it does some kind of query/lookup to identify the real destination location. If you stick this functionality directly in the end hosts themselves, then you have SHIM6. If you stick the functionality in the provider edge router then you have MPLS. --Michael Dillon
Current thread:
- Re: And Now for Something Completely Different (was Re: IPv6 news), (continued)
- Re: And Now for Something Completely Different (was Re: IPv6 news) David Conrad (Oct 18)
- Re: And Now for Something Completely Different (was Re: IPv6 news) Elmar K. Bins (Oct 18)
- Re: And Now for Something Completely Different (was Re: IPv6 news) Tony Li (Oct 18)
- Re: And Now for Something Completely Different (was Re: IPv6 news) David Conrad (Oct 18)
- Re: And Now for Something Completely Different (was Re: IPv6 news) Per Heldal (Oct 19)
- Re: And Now for Something Completely Different (was Re: IPv6 news) Joe Abley (Oct 16)
- Re: And Now for Something Completely Different (was Re: IPv6 news) Valdis . Kletnieks (Oct 16)
- Re: And Now for Something Completely Different (was Re: IPv6 news) Joe Abley (Oct 16)
- Re: And Now for Something Completely Different (was Re: IPv6 news) Paul Vixie (Oct 16)
- Re: IPv6 news Paul Vixie (Oct 16)
- Re: IPv6 news Michael . Dillon (Oct 17)
- Re: IPv6 news David Conrad (Oct 18)
- RE: IPv6 news Scott Morris (Oct 16)
- Re: IPv6 news Paul Vixie (Oct 16)
- Re: IPv6 news Mike Leber (Oct 15)
- shim6 (was Re: IPv6 news) David Conrad (Oct 14)
- Re: shim6 (was Re: IPv6 news) Owen DeLong (Oct 14)
- Re: shim6 (was Re: IPv6 news) Joe Abley (Oct 14)
- Re: shim6 (was Re: IPv6 news) Joe Abley (Oct 14)
- Re: shim6 (was Re: IPv6 news) bmanning (Oct 14)
- Re: shim6 (was Re: IPv6 news) william(at)elan.net (Oct 14)