Dear all, The following describes a mechanism for "Cross Notification in the Routing Registry" to be implemented shortly at the RIPE NCC. The mechanism has been modified to incorporate the feedback received during RIPE 27. Appended is a short history explaining how the proposal reached its current form. If this mechanism is of interest to you, please review the document and send any comments or questions you may have to myself. Unless we hear show stoppers, we will start the implementation in the week of July 21, 1997. Greetings, Carol Orange, RIPE NCC -------------------------------------------------------------------- Cross Notification in the Routing Registry Carol Orange, July 1997 Suppose you register the announcement of a route covering some /24. When you make the announcement, it may be useful to know that the /24 has already been registered as being announced in another AS. Alternatively, if a user of a /24 which is announced by you decides to become multi-homed, it may be of interest to you. Overlapping routes are often unintentionally announced in a single AS, and a mechanism for detecting such errors would certainly be handy. In the following, we propose a simple cross notification mechanism which will allow routing registry users to be notified of overlapping route announcements in the Routing Registry (RR). Consider the route object: route: [mandatory] [single] [primary/look-up key] descr: [mandatory] [multiple] [ ] origin: [mandatory] [single] [primary key] hole: [optional] [multiple] [ ] withdrawn: [optional] [single] [ ] comm-list: [optional] [multiple] [ ] advisory: [optional] [multiple] [ ] remarks: [optional] [multiple] [ ] notify: [optional] [multiple] [inverse key] mnt-by: [mandatory] [multiple] [inverse key] changed: [mandatory] [multiple] [ ] source: [mandatory] [single] [ ] To address the considerations above, we propose the following notification mechanism be implemented in the Routing Registry: 1. Whenever a route object is added to the routing registry, a check is done to see if the address space overlaps with that in any other route object in the RR. If so, a notification will be sent to the submitter of the route object. This will always happen and is not dependent on any notification attributes described below. 2. A new field called "cross-nfy:" will be added to the route and aut-num objects. This field: a) contains a contact reference, specified as either + a NIC-handle pointing to a person or role object, the email address of which will get the notification; or + a mntner ID referencing the maintainer to be notified; b) is optional; and c) is multiple (so that more than one contact can be notified). This attribute is used to request notifications of the addition or removal of route objects which overlap the address space of the already registered route objects in which this attribute is specified. If the "cross-nfy:" attribute is used in: + a route object, then a notification will be sent for any overlaps with the address space specified in the route object; + an aut-num object, then a notification will be sent for overlaps with the address space specified in each route object in which the given AS number is specified in the "origin:" attribute. The contact in "cross-nfy:" will receive an e-mail whenever: + a route is registered which overlaps this address space; or + a route is removed which overlapped this address space. If all is well, the former will indicate the introduction of multi-homing, and the latter will indicate the cancellation of the multi-homing. It is expected, however, that the former will often indicate an error, and the latter its removal. Either way, it will be useful to know about the registration and elimination of overlapping announcements. Some Important Notes -------------------- 1. At the time of implementation, the notification may take up to 24 hours, due to the current mirroring scheme employed in the RR. This time will be reduced when the mirroring scheme is improved. 2. Exact address space matches will be distinguished from non-exact overlaps in the notification messages. 3. After the implementation of RPSL, it will be useful to allow one or more route-sets to be specified in the "cross-nfy:" attribute in addition to the contact reference. For example, using: cross-nfy: <ContactA> <route-set1> <route-set3> cross-nfy: <ContactB> <route-set2> in an aut-num object would allow ContactA to be notified upon registration and deletion of routes overlapping the address space covered in <route-set1> and <route-set3> and ContactB to be notified with regards to route registrations with address space overlapping that covered in <route-set2>. In this way, a more selective notification scheme can be specified without adding "cross-nfy:" to every route object. Acknowledgements ---------------- Thanks to the RIPE Routing and Database working groups for lively discussions resulting in constructive input on this notification mechanism. Daniel Karrenberg was the first to mention the need for a notification mechanism in the RR. Chris Fletcher, Joachim Schmitz and Wilfried Woeber have all made essential contributions. ------------- ------------- ------------- ------------ ------------- Appendix - Some History At the January meeting of the Routing WG in Amsterdam, various possible hierarchies for authorization in the Routing Registry (RR) were considered. During the discussion, a suggestion was made that "hierarchical notification" would be useful even in cases where authority is not well defined. This suggestion enjoyed strong support of both the Routing WG and the Database WG. At the start of May 1997, a proposal was submitted to the mailing lists of the RIPE Routing and Database WG's describing a notification mechanism designed to meet the stated requirements. During the RIPE meeting in Dublin, it was agreed to that the notification mechanism should be implemented, with the following modifications: 1. Whenever a route object is submitted in the RR, a notification should be generated to the submitter if the address space overlaps with any other route object in the RR. [RIPE27 - Routing WG meeting] 2. The attribute should be named "cross-nfy:" rather than "x-notify:" to avoid any misunderstandings with respect to other conventions. In particular, mailers often interpret "X-field:" to mean "ignore this field". [private discussion Chris Fletcher] 3. If the address space covered in the route object matched the address space in another route object, be sure this is clear in the notification message. [RIPE27 - Routing WG meeting] 4. - Notifications should be sent to the appropriate contact not only if an overlap is introduce, but also when an overlap is eliminated. [RIPE27 - Routing WG meeting] 5. The "cross-nfy:" field should be available for the "aut-num:" object as well as for the routing object. If "cross-nfy:" is in the "aut-num:" object, it applies to all routes with that aut-num as origin. [RIPE27 - Database WG meeting] It has since been suggested that it would be useful if the mechanism would be extensible for the "route-set:" objects defined in RPSL (see draft-ietf-rps-rpsl-02). To make use of the route grouping functionality supplied by the "route-set:" object, we suggest the following extension be considered: 6. In the "aut-num:" object, allow "cross-nfy:" to be a multiple attribute, and in addition to specifying who should be notified, specify for which route-sets. If no route-sets are specified, then the notification will take place for all route objects with the given "aut-num:" as origin. [private discussion Joachim Schmitz]