An attempt to clean up the text so far: REQ-2: Transparency to Upper Layers The DMM solutions SHALL provide transparency above the IP layer when needed. Such transparency is needed, when the mobile hosts or entire mobile networks change their point of attachment to the Internet, for the application flows that cannot cope with a change of IP address, but SHOULD NOT be taken as the default behavior.
REQ-2M (Motivation for REQ-2) The goal of this requirement is to enable more efficient use of network resources and more efficient routing when mobility support is implemented by not invoking it for the application flows and nodes that do not need it. RELEVANT problem: PS5: Wasting resources to support mobile nodes not needing mobility support IP mobility support is not always required. For example, some applications do not need a stable IP address during handover, i.e. IP session continuity. Sometimes, the entire application session runs while the terminal does not change the point of attachment. In these situations that do not require IP mobility support, network resources are wasted when including additional info to the mobility context to support the change the point of attachment. Network resources are also wasted when the via routes are set up for many MNs that do not require IP mobility support. OTHER related problem O-PS1: Mobility signaling overhead with peer-to-peer communication While mobility management enables a mobile host to be reachable, the hosts may then communicate directly so that the mobility support is no longer needed. Taking the need of mobility support as the default behavior will waste network resources. O-PS2: Lack of user-centricity Centralized deployment compared with distributed mobility management may be less capable to support user-centricity. Example in the lack of user-centricity is to provide mobility support to all mobile nodes by default regardless of whether the user needs it or not. H Anthony Chan -----Original Message----- From: Peter McCann Sent: Friday, May 18, 2012 9:35 AM To: jouni korhonen; h chan Cc: [email protected] Subject: RE: [DMM] draft requirement REQ-2: Transparency to Upper Layers Hi, Jouni, jouni korhonen wrote: > > Few comments/questions here: > > On May 7, 2012, at 8:58 PM, h chan wrote: > >> REQ-2: Transparency to Upper Layers >> The DMM solutions SHALL enable transparency above the IP layer. Such >> transparency is needed for the application flows that cannot cope with >> a change of IP address and when mobile hosts or entire mobile networks >> change their point of attachment to the Internet, but SHOULD NOT be >> taken as the default behavior. > > "SHALL enable" but "SHOULD NOT be taken as the default behavior" seem > to conflict. So, what is really meant here? Does this mean something > like "MUST implement, SHOULD use" type of solution? Or can one leave > transparency completely away if the applications/hosts just don't care > whether IP changes or not? I think the latter. If the applications don't care about transparency, then we don't need to pay for it with state and signaling in the network. However, we know that some applications do care, so it SHALL be possible to provide it. >> REQ-2M (Motivation for REQ-2) >> The goal of this requirement is to >> enable more efficient use of network resources and more efficient >> routing by not invoking mobility support when there is no such need. > > Does this still mean the mobility support must be implement even if it > is not used? We need some strategy for keeping an IP address through some amount of mobility. However, we needn't optimize the network for this case as it might be rather uncommon to keep an address for a very long period of time. >> RELEVANT problem: >> PS5: Wasting resources to support mobile nodes not needing mobility >> support IP mobility support is not always required. For example, >> some >> applications do not need a stable IP address during handover, i.e. IP >> session continuity. Sometimes, the entire application session runs >> while the terminal does not change the point of attachment. In these >> situations that do not require IP mobility support, network resources >> are wasted when mobility context is set up. Network resources are also >> wasted when the via routes are set up for many MNs that do not require >> IP mobility support. >> >> OTHER related problem >> O-PS1: Mobility signaling overhead with peer-to-peer communication >> While mobility management enables a mobile host to be reachable, the >> hosts may then communicate directly so that the mobility support is no >> longer needed. Taking the need of mobility support as the default >> behavior will waste network resources. >> O-PS2: Lack of user-centricity >> Centralized deployment compared with distributed mobility management >> may be less capable to support user-centricity. Example in the lack of >> user-centricity is to provide mobility support to all mobile nodes by >> default regardless of whether the user needs it or not. > > I have issues to parse O-PS2.. the motivation makes sense though but > the title "lack of user-centricity" is somewhat confusing.. what does > forced/always-on mobility support has to do with user centricity? I think Anthony just meant that we should tailor the mobility management to the needs of the user. I wouldn't mind seeing this explanatory text re-worded. -Pete > > - Jouni > > >> >> (The above has been drafted with contributions, inputs and discussions >> from various people. Additional contributions and comments are most >> welcome.) >> >> H Anthony Chan >> >> >> _______________________________________________ >> dmm mailing list >> [email protected] >> https://www.ietf.org/mailman/listinfo/dmm > > _______________________________________________ > dmm mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/dmm _______________________________________________ dmm mailing list [email protected] https://www.ietf.org/mailman/listinfo/dmm
