Re: ISP and NAT (question and some thoughts)
just a thought... why not expand the IPv4 address field using the 'Fragment offset' and 'Identification' fields? Use those fields to mark packets at the edge with the destination AS number, for example. Customer equipment could use private address space and not bother with the edge remarking process. (I know that the fragmentation function would be lost due to this 'extension'.) (I am also aware of transitioning problems related to what I am proposing; the routers in the network cannot be upgrade all at once...) thoughts/comments? jld. "Alex P. Rudnev" <alex@virgin.relcom.eu.net> on 10/18/99 12:46:50 PM To: nanog@merit.edu cc: (bcc: Jeanlou Dupont/RMQ/RELTECCORP) Subject: ISP and NAT (question and some thoughts) Today we see the classical schema ISP/customer; this means - the customer have his own address space, requested by him (directly or undirectly) - due to the lack of public addresses, the customers are forced to use NAT; just NAT provide some extra security - ISP do not provide NAT themself; NAT configuration is not easy task and cause a lot of headache for the customers (just as a lot of money they pay to the network admins). First question - is this picture right or it is wrong? The second question. What prevent the _future ISP_ from some another schema, when: - the customer always use the private address space, for example, 10.0.0.0/8; - the provider bother about address translation, just as about name translation (DNS re-writing), just as about the address allocation (not the customer but the provider - if existing address space is not enough); - the providers's software learn about _open, or public_ services which must be translated statically, from the customer using (for example) DNS. Don't answer _it's too slow_. This is my attempt to predict where we are going this days. Today the _know-how_ the customer should know is too huge - if (if I am the admin of the company, not ISP!) I open electronic market or want to get Internet for the companies employees, I must allocate space (why? What for? It's not my concern, if we think a little), I must prove I need this addresses (why? This is my business how much addresses I need internally; and let's software decide how much addresses I need externally), and I should configure firewalls and NAT's. We used to think about it as about the normal admin's knowledge; but why we are sure it's normal. If you got a car (in USA, not in the Russia), you don't bother about the oil stations or about the roads - you just use it. This is not really a dump question. If it is possible to build such Internet service when every customer should be free to use any address space in the hidden way, and ISP (not the customer) bother about the global address and name translation, we should have just this hierarchical address schema IPv6 offer to us. On the other hand, it means a great increase in the NAT engine. Aleksei Roudnev, Network Operations Center, Relcom, Moscow (+7 095) 194-19-95 (Network Operations Center Hot Line),(+7 095) 230-41-41, N 13729 (pager) (+7 095) 196-72-12 (Support), (+7 095) 194-33-28 (Fax)
The problem with the address space is not in the packets themself (the IP address can be _easily_ increased by the source-routing, for example); the primary problem is in the existing applications which has only 1 DST ip address and 1 DST port. The address space can be increased by the DST-port space, but DST port exist only at the L4 (if we treat IP as L3 and TCP as L4, don't blame me please) level and this prevent a lot of Internat interaction (ICMP interaction, for example) from work. NAT does the same, but in the hidden manner, and it can use IP<->IP direct translation if necessary. There was a few papers sent here, all with the same mistake - the lack of address space exist not in the IP packet (use the pair PROVIDER,CUSTOMER) address schema to deliver the packet, with the SO option; but in the TCP, UDP and other IP stacks (TCP connection is identified ny the DST(A,P),SRC(A,P) set of parameters, where to place PROVIDER address here). On the other hand, NAT engine became more and more robust, it allow to do more and more with it; but just this make this engine more and more complex - too complex for the end customer... This was the core reason of my message below. / All written was not the set of axioms, of course. Alex. On Mon, 18 Oct 1999 jeanlou.dupont@na.marconicomms.com wrote:
Date: Mon, 18 Oct 1999 13:13:18 -0400 From: jeanlou.dupont@na.marconicomms.com To: Alex P. Rudnev <alex@virgin.relcom.eu.net> Cc: nanog@merit.edu Subject: Re: ISP and NAT (question and some thoughts)
just a thought...
why not expand the IPv4 address field using the 'Fragment offset' and 'Identification' fields? Use those fields to mark packets at the edge with the destination AS number, for example. Customer equipment could use private address space and not bother with the edge remarking process. (I know that the fragmentation function would be lost due to this 'extension'.) (I am also aware of transitioning problems related to what I am proposing; the routers in the network cannot be upgrade all at once...)
thoughts/comments?
jld.
"Alex P. Rudnev" <alex@virgin.relcom.eu.net> on 10/18/99 12:46:50 PM
To: nanog@merit.edu cc: (bcc: Jeanlou Dupont/RMQ/RELTECCORP)
Subject: ISP and NAT (question and some thoughts)
Today we see the classical schema ISP/customer; this means - the customer have his own address space, requested by him (directly or undirectly) - due to the lack of public addresses, the customers are forced to use NAT; just NAT provide some extra security - ISP do not provide NAT themself; NAT configuration is not easy task and cause a lot of headache for the customers (just as a lot of money they pay to the network admins).
First question - is this picture right or it is wrong?
The second question. What prevent the _future ISP_ from some another schema, when: - the customer always use the private address space, for example, 10.0.0.0/8; - the provider bother about address translation, just as about name translation (DNS re-writing), just as about the address allocation (not the customer but the provider - if existing address space is not enough); - the providers's software learn about _open, or public_ services which must be translated statically, from the customer using (for example) DNS.
Don't answer _it's too slow_.
This is my attempt to predict where we are going this days. Today the _know-how_ the customer should know is too huge - if (if I am the admin of the company, not ISP!) I open electronic market or want to get Internet for the companies employees, I must allocate space (why? What for? It's not my concern, if we think a little), I must prove I need this addresses (why? This is my business how much addresses I need internally; and let's software decide how much addresses I need externally), and I should configure firewalls and NAT's. We used to think about it as about the normal admin's knowledge; but why we are sure it's normal. If you got a car (in USA, not in the Russia), you don't bother about the oil stations or about the roads - you just use it.
This is not really a dump question. If it is possible to build such Internet service when every customer should be free to use any address space in the hidden way, and ISP (not the customer) bother about the global address and name translation, we should have just this hierarchical address schema IPv6 offer to us. On the other hand, it means a great increase in the NAT engine.
Aleksei Roudnev, Network Operations Center, Relcom, Moscow (+7 095) 194-19-95 (Network Operations Center Hot Line),(+7 095) 230-41-41, N 13729 (pager) (+7 095) 196-72-12 (Support), (+7 095) 194-33-28 (Fax)
Aleksei Roudnev, Network Operations Center, Relcom, Moscow (+7 095) 194-19-95 (Network Operations Center Hot Line),(+7 095) 230-41-41, N 13729 (pager) (+7 095) 196-72-12 (Support), (+7 095) 194-33-28 (Fax)
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