Hi Alper, For an application developer, if there are three kinds of addresses to use which are "Fixed IP Address", "Sustained IP Address" and "Nomadic IP Address",
then I believe the developer would always wants to use the "Fixed IP address", rather than the other ones. Because even though the application could cope with IP address change, but the IP address change is not what the application want. -Xinpeng ________________________________ 发件人: Alper Yegin [[email protected]] 发送时间: 2015年3月27日 2:13 收件人: Weixinpeng (Jackie) 抄送: Dapeng Liu; [email protected] 主题: Re: Re： DMM API Hi Xinpeng, If your app knows how to deal with IP address changes, then it's better if we give it a chance to do so, because (as the I-D explains): Achieving IP session continuity and IP address reachability by using Mobile IP incurs some cost. Mobile IP protocol forces the mobile host's IP traffic to traverse a centrally-located router (Home Agent, HA), which incurs additional transmission latency and use of additional network resources, adds to the network CAPEX and OPEX, and decreases the reliability of the network due to the introduction of a single point of failure [I-D.ietf-dmm-requirements]. Therefore, IP session continuity and IP address reachability should be be provided only when needed. Alper On Mar 26, 2015, at 7:39 PM, Weixinpeng (Jackie) wrote: Hi Alper My understanding about the reason why there needs to define serval types of IP prefixes is that, if the application itself could deal with the change of IP address, i.e. the application itself could deal with session continuty in case of IP address change, so the host would choose a normadic address otherwise the host should choose a sustained address. But my question is that, if the application could deal with session continuty itself, does that mean the application is willing to change its IP address? Because even though a new address might bring some kinds of benefit, but it will also bring additional cost for application to deal with IP address change. Thanks. Xinpeng ________________________________ 发件人: dmm [[email protected]<mailto:[email protected]>] 代表 Dapeng Liu [[email protected]<mailto:[email protected]>] 发送时间: 2015年3月26日 5:01 收件人: Alper Yegin 抄送: [email protected]<mailto:[email protected]> 主题: [DMM] 回复： DMM API Hello Alper, I still have the following comments: 1. Regarding the definition of “fixed IP address” in the draft: “- Fixed IP Address This is what standard Mobile IP provides with a Home Address (HoA). The mobile host is configures a HoA from a centrally-located Home Network. Both IP session continuity and IP address reachability are provided to the mobile host with the help of a router in the Home Network (Home Agent, HA). This router acts as an anchor for the IP address of the mobile host.” If this is equal to HoA, then RFC5014 already cover that. We do not need to repeat it here with another name. 2. Regarding the definition of “sustained IP address” in the draft: "- Sustained IP Address This type of IP address provides IP session continuity but not IP address reachability. It is achieved by ensuring that the IP address used at the beginning of the session remains usable despite the movement of the mobile host. The IP address may change after the termination of the IP session(s), therefore it does not exhibit persistence. " There is no clear dividing line between fixed IP address and sustained IP address. Whether the IP address is used for reachability is not determined by the IP address itself. For example, even when the MN get a HoA, after it moves to another location of the network, it may decide to release current HoA and get another HoA, in this case the "fixed IP address" becomes a "sustained IP address". Further more, the reachability normally is implemented by domain name instead of IP address. For example, we reach “Google” by its domain name, never by it’s server’s IP address. Using temporary private IP address we can also achieve the goal of “reachability”. For example, using dynamic DNS, as shown in http://hsk.oray.com/ , it can provide reachability even the host get a private IP address. 3. Regarding the definition of “nomadic IP address”: “- Nomadic IP Address This type of IP address provides neither IP session continuity nor IP address reachability. The IP address is obtained from the serving IP gateway and it is not maintained across gateway changes. In other words, the IP address may be released and replaced by a new IP address when the IP gateway changes due to the movement of the mobile host.” Seems this IP address is the IP address that we normally used in most cases. If this is the case, why we need a new name for it? -- Dapeng Liu 在 2015年3月25日 星期三，下午2:02，Alper Yegin 写道： Hello Dapeng and Alex, I hope you had a chance to digest our responses to your comments and questions about the API work. If you have any remaining issues, please let us know over the email at your earliest convenience. It'd be good if you can articulate them in detail. Thanks. Alper
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