RFC 2098 (rfc2098) - Page 2 of 18
Toshiba's Router Architecture Extensions for ATM : Overview
Alternative Format: Original Text Document
RFC 2098 Toshiba's Router Extension for ATM February 1997
- It makes the best use of ATM's property while retaining current
router-based internetworking and routing architecture.
- It takes into account interoperability with future IP that
supports flow concept and resource reservations.
Section 2 of this draft explains background and motivations of our
proposal. Section 3 describes an overview of the proposed
internetworking architecture and its several remarkable features.
Section 4 discusses control architectures for CSR, which will need to
be further investigated.
2. Background and Motivation
It is considered that the current hop-by-hop best effort datagram
forwarding paradigm will not be adequate to support future large
scale Internet which accommodates huge amount of traffic with certain
QoS requirements. Two major schools of investigations can be seen in
IETF whose main purpose is to improve ability of the Internet with
regard to its throughput and QoS. One is to utilize ATM technology
as much as possible, and the other is to introduce the concept of
resource reservation and flow into IP.
1) Utilization of ATM
Although basic properties of ATM; necessity of connection setup,
necessity of traffic contract, etc.; is not necessarily suited to
conventional IP datagram transmission, its excellent throughput and
delay characteristics let us to investigate the realization of IP
datagram transmission over ATM.
A typical internetworking architecture is the "Classical IP Model"
[RFC 1577]. This model allows direct ATM connectivities only between
nodes that share the same IP address prefix. IP datagrams should
traverse routers whenever they go beyond IP subnet boundaries even
though their source and destination are accommodated in the same ATM
cloud. Although an ATMARP is introduced which is not based on legacy
datalink broadcast but on centralized ATMARP servers, this model does
not require drastic changes to the legacy internetworking
architectures with regard to the IP datagram forwarding process.
This model still has problems of limited throughput and large
latency, compared with the ability of ATM, due to IP header
processing at every router. It will become more critical when
multimedia applications that require much larger bandwidth and lower
latency become dominant in the near future.
Katsube, et. al. Informational