Hi, Xiaohu,
I just show how IP Gateway works, not show how SARP works. Eric
already shows how SARP works, I do not want to repeat. You misunderstand my
meanings, I just want to show how similar between IP Gateway and SARP.
Please go through the thread. (I have to cut the previous mails
because the mail size limitations from IETF)
Hewen
From: Xuxiaohu [mailto:[email protected]]
Sent: Friday, October 11, 2013 1:11 PM
To: Zhenghewen; 'Eric Gray'; [email protected]
Subject: 答复: [Int-area] FW: Re: Call for adoption of draft-nachum-sarp
发件人: [email protected] [mailto:[email protected]] 代表 Zhenghewen
发送时间: 2013年10月11日 11:25
收件人: 'Eric Gray'; [email protected]
主题: Re: [Int-area] FW: Re: Call for adoption of draft-nachum-sarp
Hi, Eric,
I have the same understanding with you about the behaviour of
SARP, but I do not think that it is NAT, I think that it is more similar to
Gateway.
Let’s reuse your figure,
IP-S
IP-D
ES-1 T-W T-E
ES-2
[MAC-S] ------(?) (MAC-W)------(MAC-E) (?)------[MAC-D]
S-A S-B
S-C
Now, let’s assume that T-W is the gateway for ES-1 and T-E is
the gateway for ES-2,
For traffic going West-to-East:
In the ARP model, T-W responds to an ARP request from ES-1 for IP-D with MAC-W.
[Xiaohu] I think you misunderstand the concept of SARP. ES-1 is expected to
receive an ARP reply containing a mapping from IP-D to MAC-E, rather than a
mapping from IP-D to MAC-W. Therefore, the following illustration is also
wrong.
Xiaohu
In traditional IP routing model:
o ES-1 sends a frame with (D-MAC=MAC-W, S-MAC=MAC-S) to T-W;
o T-W translate S-MAC=MAC-S to S-MAC=MAC-W, translate D-MAC=MAC-W
to D-MAC=MAC-E, and forwards the frame (otherwise as is) to T-E
o T-E translates D-MAC=MAC-E to D-MAC=MAC-D according to IP-D, and
forwards the frame to ES-2.
Now, do we think that the gateway T-W and T-E also provide MAC-NAT function?
I think that SARP use some mechanism like MAC-Gateway to hide hosts’ MAC
address from outer data centers. It does not purely work via simple address
mapping (for example, IP NAT or PNAT), it works with help IP-MAC host-route
like the IP gateway, so I think it is not MAC-NAT.
Hewen
(In the first try to response your mail, the response is blocked by the IETF
mail system because "Message body is too big: 52215 bytes with a limit of 40 KB
", so I have to retry after deleting some previous info; If IETF mail system
finally let the first response go, please ignore it, sorry the duplicated mail)
From: Eric Gray [mailto:[email protected]]
Sent: Friday, October 11, 2013 12:26 AM
To: Zhenghewen; [email protected]
Subject: RE: [Int-area] FW: Re: Call for adoption of draft-nachum-sarp
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