Unified Routing Requirements for IPng (RFC1668)
Original Publication Date: 1994-Aug-01
Included in the Prior Art Database: 2000-Sep-12
Internet Society Requests For Comment (RFCs)
D. Estrin: AUTHOR [+3]
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 firstname.lastname@example.org mailing list.
Network Working Group D. Estrin
Request for Comments: 1668 USC
Category: Informational T. Li
T.J. Watson Research Center, IBM Corp.
Unified Routing Requirements for IPng
Status of this Memo
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.
1. IPng Requirements
The following list provides requirements on the IPng from the
perspective of the Unified Routing Architecture, as describe in RFC
1. To provide scalable routing, IPng addressing must provide support
for topologically significant address assignment.
2. Since it is hard to predict how routing information will be
aggregated, the IPng addressing structure should impose as few
preconditions as possible on the number of levels in the hierarchy.
Specifically, the number of levels must be allowed to be different
at different parts in the hierarchy. Further, the levels must not
be statically tied to particular parts (fields) in the addressing
3. Hop-by-hop forwarding algorithm requires IPng to carry enough
information in the Network Layer header to unambiguously determine
a particular next hop. Unless mechanisms to compute
context-sensitive forwarding tables and provide consistent
forwarding are defined, the requirement assumes the presence of
full hierarchical addresses. Therefore, IPng packet format must
provide efficient determination of the full hierarchical
4. Hierarchical address assignment should not imply strictly
hierarchical routing. Therefore, IPng should carry enough
information to provide forwarding along both hierarchical and
5. The IPng packet header should accommodate a "routing label" or
"route ID". This label will be used to identify a particular FIB
to be used for packet forwarding by each router.
Two types of routing labels should be supported: "strong" and
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 FI...