Comments inline. -----Original Message----- From: Charlie Perkins [mailto:[email protected]] Sent: Monday, January 22, 2018 11:54 AM To: Bertz, Lyle T [CTO] <[email protected]>; Marco Liebsch <[email protected]> Cc: [email protected] Subject: Re: Parent versus child mobility context
Hello Lyle and all, I think I agree with most of what you say below. I'm concerned with how to organize the information in the model. So, for that purpose, please verify whether my following understandings are correct. - The mobility context resides on a DPN. - The mobility context provides necessary information (e.g., QoS) for a single mobile node. - The DPN uses it to manage data-plane traffic for that mobile node. >> This may be too broad of a view. What about a mobile node with multiple >> mobility sessions? In such a case it may be managing one or more (but not >> necessarily all of) the mobile node's mobility sessions - Your description seems to imply that there are separate mobility contexts for each mobility session (i.e., for each bearer, or flow) that terminates (or originates) on the mobile node. >> Yes. In my earlier email on this subject, I was using Mobility Context as describing something more associated with a mobile node, than with a particular flow. If you want it to mean "bearer", then we ought to call it a Bearer. Maybe it would be easier to understand if we had something called a "Mobile-Node Context", and in that context we had a set of Bearer Contexts (or, just Bearers). Each bearer would inherit from the Mobile Node context simply by being part of it. The Mobile Node context (serving as "parent") would determine max bandwidth, IP address, etc. Back in the old days, we also defined security aspects and some other factors, as part of what FPC would call the "mobility context". >> We have several concepts that have hierarchy, e.g. Service Level (sr-id or >> APN - apn-oi if I recall), device level, Mobility Session, bearers, flow >> based filters (effectively living within a bearer). We also have the 5G >> concepts as well. The one thing that is obvious is that the idea of >> hierarchy applies whether it is pacers/shapers, bearers or filters that >> apply some charging / gating / marking. A light touch of lifecycle (fate >> sharing) amongst the hierarchy, data does not need to be repeated within >> the hierarchy and building the data structure by requiring a parent id if it >> was a child (implying the parent must exist!) was the best we could do >> without necessarily making decisions that may appear to preclude a specific >> set of mobile network technologies. If you really want to maintain Parent Context and Child Context as independent structure elements, then we need to make a new indexed set for them. >> We just used a pointer from a Context to a Parent Context. If the value was >> non-empty it was a child and the parent Id must point to a valid Context. Regards, Charlie P. On 1/22/2018 5:30 AM, Bertz, Lyle T [CTO] wrote: > ++ mailing list > > I agree with you Marco. > > Keeping the parent/child relation is crucial. Although we often cite > dedicated vs. default bearers (LTE) we need to also ack that we use > hierarchical concepts throughout mobility and forwarding management > protocols, e.g. meters, session and sub-session (includes accounting), etc. > > Lifecycle association here (fate sharing of the children with the parent) is > an important concept. Many of the mobility systems assume gateways (LMAs and > MAGs) have knowledge of the relationships between sessions and sub-session > and will often kill the session in order to reduce signaling overhead. They > also assume when installing a session / sub-session that any violation of > hierarchy rules, e.g. setting a child's max bit rate above a parent's, would > be properly enforced, i.e. it is an error or the child's value is ignored. > > For FPC we also use it to avoid sending redundant data (does one need > to send the mobile's IP address for any sort of sub-session work if it > is tied to a parent that already has it?) > > -----Original Message----- > From: Marco Liebsch [mailto:[email protected]] > Sent: Monday, January 22, 2018 5:49 AM > To: Charlie Perkins <[email protected]>; Bertz, Lyle T > [CTO] <[email protected]> > Cc: Satoru Matsushima <[email protected]>; Sri Gundavelli > (sgundave) <[email protected]>; Moses, Danny <[email protected]>; > Weaver, Farni [CTO] <[email protected]>; Matsushima Satoru > <[email protected]> > Subject: RE: Parent versus child mobility context > > That has been introduced to reflect e.g. dedicated bearers which come on top > of default bearers hence have some level of dependency. If context associated > with a default bearer gets closed, dependent context will follow. To me it > makes sense. Others? > > marco > > -----Original Message----- > From: Charlie Perkins [mailto:[email protected]] > Sent: Montag, 22. Januar 2018 06:29 > To: Bertz, Lyle T [CTO] > Cc: Marco Liebsch; Satoru Matsushima; Sri Gundavelli (sgundave); > Moses, Danny; Weaver, Farni [CTO]; Matsushima Satoru > Subject: Parent versus child mobility context > > > Hello folks, > > I have looked at this several times, and I would like to propose simplifying > it to simply be a mobility context. I don't see that the extra complication > is worth it, especially right now. If, in the future, we need it for > something, we could put it back in. > > Thanks for your consideration of this request. > > Regards, > Charlie P. > > ________________________________ > > This e-mail may contain Sprint proprietary information intended for the sole > use of the recipient(s). Any use by others is prohibited. If you are not the > intended recipient, please contact the sender and delete all copies of the > message. _______________________________________________ dmm mailing list [email protected] https://www.ietf.org/mailman/listinfo/dmm
