{"action":"created","issue":{"url":"https://api.github.com/repos/OpenMobileAlliance/OMA_LwM2M_for_Developers/issues/137","repository_url":"https://api.github.com/repos/OpenMobileAlliance/OMA_LwM2M_for_Developers","labels_url":"https://api.github.com/repos/OpenMobileAlliance/OMA_LwM2M_for_Developers/issues/137/labels{/name}","comments_url":"https://api.github.com/repos/OpenMobileAlliance/OMA_LwM2M_for_Developers/issues/137/comments","events_url":"https://api.github.com/repos/OpenMobileAlliance/OMA_LwM2M_for_Developers/issues/137/events","html_url":"https://github.com/OpenMobileAlliance/OMA_LwM2M_for_Developers/issues/137","id":175425166,"number":137,"title":"Observation lifetime, registration interface, and DTLS sessions","user":{"login":"boaks","id":10937819,"avatar_url":"https://avatars.githubusercontent.com/u/10937819?v=3","gravatar_id":"","url":"https://api.github.com/users/boaks","html_url":"https://github.com/boaks","followers_url":"https://api.github.com/users/boaks/followers","following_url":"https://api.github.com/users/boaks/following{/other_user}","gists_url":"https://api.github.com/users/boaks/gists{/gist_id}","starred_url":"https://api.github.com/users/boaks/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/boaks/subscriptions","organizations_url":"https://api.github.com/users/boaks/orgs","repos_url":"https://api.github.com/users/boaks/repos","events_url":"https://api.github.com/users/boaks/events{/privacy}","received_events_url":"https://api.github.com/users/boaks/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":1,"created_at":"2016-09-07T06:44:17Z","updated_at":"2016-09-27T16:14:23Z","closed_at":null,"body":"Though https://github.com/OpenMobileAlliance/OMA_LwM2M_for_Developers/issues/71 started a discussion about observation lifetime according the registration interface, I got aware, that if the DTLS session was broken and a new DTLS session is created, this will also stop the notifies (caused by the definition, that a request and a response mus share teh same DTLS session and epoch for security reasons). \r\nTherefore, a client, which get's aware of a new DTLS session seems currently to be forced to do a registration and not using a \"register update\".\r\nSo the LWM2M TS should add more details of the influence of the DTLS to the upper layers.\r\n\r\n"},"comment":{"url":"https://api.github.com/repos/OpenMobileAlliance/OMA_LwM2M_for_Developers/issues/comments/249915062","html_url":"https://github.com/OpenMobileAlliance/OMA_LwM2M_for_Developers/issues/137#issuecomment-249915062","issue_url":"https://api.github.com/repos/OpenMobileAlliance/OMA_LwM2M_for_Developers/issues/137","id":249915062,"user":{"login":"DanielMaier-BSI","id":9269795,"avatar_url":"https://avatars.githubusercontent.com/u/9269795?v=3","gravatar_id":"","url":"https://api.github.com/users/DanielMaier-BSI","html_url":"https://github.com/DanielMaier-BSI","followers_url":"https://api.github.com/users/DanielMaier-BSI/followers","following_url":"https://api.github.com/users/DanielMaier-BSI/following{/other_user}","gists_url":"https://api.github.com/users/DanielMaier-BSI/gists{/gist_id}","starred_url":"https://api.github.com/users/DanielMaier-BSI/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/DanielMaier-BSI/subscriptions","organizations_url":"https://api.github.com/users/DanielMaier-BSI/orgs","repos_url":"https://api.github.com/users/DanielMaier-BSI/repos","events_url":"https://api.github.com/users/DanielMaier-BSI/events{/privacy}","received_events_url":"https://api.github.com/users/DanielMaier-BSI/received_events","type":"User","site_admin":false},"created_at":"2016-09-27T16:14:23Z","updated_at":"2016-09-27T16:14:23Z","body":"Any other thoughts about this issue?\r\n\r\nHere are mine:\r\n\r\nAn alternative approach to re-register the client after new DTLS handshake would be that the server needs to be aware of the new handshake from lower levels (DTLS layer) and re-establish the observe relations. \r\n\r\nAnother alternative would be to relax the requirement that the response needs to be in the same DTLS session and epoch to the requirement that each response needs to be from the same identity as the request was sent to. I suppose this has no security implications because we have always client authentication in LWM2M scenario anyways. But I think we should not differ CoAP specification for LWM2M use case, because this will be problematic when someone uses a CoAP library that is not aware of this.\r\n\r\nTo be honest I would prefer the re-register solution mentioned above by boaks.\r\n\r\nHowever, I think one of the approaches need to be specified in LWM2M TS to ensure that the server (or client) has predictable behavior."}}
{"actor":{"display_login":"DanielMaier-BSI"}}