Hi Xufeng, Good catch, I think there is a mistake here, the expected behavior is the one described in the draft. We should not use a default value for the level-x leaves. Will fix it in the next release as part of the AD review.
Brgds, Stephane From: Lsr [mailto:[email protected]] On Behalf Of Xufeng Liu Sent: Sunday, June 09, 2019 16:35 To: [email protected]; NETMOD WG Subject: [Lsr] A question on the parameter overriding in draft-ietf-isis-yang-isis-cfg In Section 2.3. and many other locations, the current IS-IS model applies the parameter overriding rule as below: [Quote]: 2.3<https://tools.ietf.org/html/draft-ietf-isis-yang-isis-cfg-35#section-2.3>. Per-Level Parameters Some parameters allow a per level configuration. In this case, the parameter is modeled as a container with three configuration locations: o a top-level container: corresponds to level-1-2, so the configuration applies to both levels. o a level-1 container: corresponds to level-1 specific parameters. o a level-2 container: corresponds to level-2 specific parameters. +--rw priority | +--rw value? uint8 | +--rw level-1 | | +--rw value? uint8 | +--rw level-2 | +--rw value? uint8 Example: <priority> <value>250</value> <level-1> <value>100</value> </level-1> <level-2> <value>200</value> </level-2> </priority> An implementation SHOULD prefer a level specific parameter over a level-all parameter. As example, if the priority is 100 for the level-1, 200 for the level-2 and 250 for the top-level configuration, the implementation should use 100 for the level-1 and 200 for the level-2. [End of Quote] In the model, all three value leaves above have a default statement “default 64”, which brings up my question for the following example: <priority> <value>250</value> <level-1> <value>100</value> </level-1> </priority> The user does not provide a configured value for level-2. According to Section 7.6.1. of RFC7950, because the default value is in use, “the server MUST operationally behave as if the leaf was present in the data tree with the default value as its value”. This means the priority value for level-2 will be 64 (the default value), so the value 250 can never take effect as intended in the above quoted Section 2.3. Is my understanding correct? Since this is a generic question, I am CC’ing NETMOD WG too. Thanks, - Xufeng _________________________________________________________________________________________________________________________ Ce message et ses pieces jointes peuvent contenir des informations confidentielles ou privilegiees et ne doivent donc pas etre diffuses, exploites ou copies sans autorisation. Si vous avez recu ce message par erreur, veuillez le signaler a l'expediteur et le detruire ainsi que les pieces jointes. Les messages electroniques etant susceptibles d'alteration, Orange decline toute responsabilite si ce message a ete altere, deforme ou falsifie. Merci. This message and its attachments may contain confidential or privileged information that may be protected by law; they should not be distributed, used or copied without authorisation. If you have received this email in error, please notify the sender and delete this message and its attachments. As emails may be altered, Orange is not liable for messages that have been modified, changed or falsified. Thank you.
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