Network Working Group D. Estrin Request for Comments: 1668 USC Category: Informational T. Li Cisco Systems Y. Rekhter T.J. Watson Research Center, IBM Corp. August 1994
This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind. Distribution of this memo is unlimited.
This document was submitted to the IETF IPng area in response to RFC 1550. Publication of this document does not imply acceptance by the IPng area of any ideas expressed within. Comments should be submitted to the email@example.com mailing list.
The following list provides requirements on the IPng from the perspective of the Unified Routing Architecture, as describe in RFC 1322.
Two types of routing labels should be supported: "strong" and "weak".
When a packet carries a "strong" routing label and a router does not have a FIB with this label, the packet is discarded (and an error message is sent back to the source).
When a packet carries a "weak" routing label and a router does not have a FIB with this label, the packet should be forwarded via a "default" FIB, i.e., according to the destination address. In addition, the packet should carry an indication that somewhere along the path the desired routing label was unavailable.
- Specification of either individual routers or collections of routers as the entities in the source route. - The option to indicate that two consecutive entities in a source route must share a common subnet in order for the source route to be valid. - Specification of the default behavior when the route to the next entry in the source route is unavailable: - The packet is discarded, or - The source route is ignored and the packet is forwarded based only on the destination address (and the packet header will indicate this action). - A mechanism to verify the feasibility of a source route.
Security issues are not discussed in this memo.
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