Toshiba's Flow Attribute Notification Protocol (FANP) Specification (RFC2129)
Original Publication Date: 1997-Apr-01
Included in the Prior Art Database: 2019-Feb-15
Internet Society Requests For Comment (RFCs)
K. Nagami: AUTHOR [+6]
This memo discusses Flow Attribute Notification Protocol (FANP), which is a protocol between neighbor nodes for the management of cut-through packet forwarding functionalities. This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind.
Network Working Group K. Nagami Request for Comments: 2129 Y. Katsube Category: Informational Y. Shobatake A. Mogi S. Matsuzawa T. Jinmei H. Esaki Toshiba R&D Center April 1997
Toshiba’s Flow Attribute Notification Protocol (FANP) Specification
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 memo discusses Flow Attribute Notification Protocol (FANP), which is a protocol between neighbor nodes for the management of cut-through packet forwarding functionalities. In cut-through packet forwarding, a router doesn’t have to perform conventional IP packet processing for received packets. FANP indicates mapping information between a datalink connection and a packet flow to the neighbor node and helps a pair of nodes manage the mapping information. By using FANP, routers (e.g., CSR; Cell Switch Router) can forward incoming packets based on their datalink-level connection identifiers, bypassing usual IP packet processing. The design policy of the FANP is;
(1) soft-state cut-through path (Dedicated-VC) management (2) protocol between neighbor nodes instead of end-to-end (3) applicable to any connection oriented datalink platform
Due to the scalability requirement, connection oriented (CO) datalink platforms, e.g., ATM and Frame Relay, are going to be used as well as connection less (CL) datalink platforms, e.g., Ethernet and FDDI. One of the important features of the CO datalink is the presence of a datalink-level connection identifier. In the CO datalink, we can establish multiple virtual connections (VCs) with their VC identifiers among the nodes. When we aggregate packets that have the same direction (e.g., having the same destination IP address) into a single VC, we can forward the packets in the VC without IP
Nagami, et. al. Informational [Page 1]
RFC 2129 FANP Specification April 1997
processing. With this configuration, routers can decide which node is the next-hop for the packets based on the VC identifier. CSRs  can forward the incoming packets using an ATM switch engine bypassing the conventional IP processing. According to the ingress VPI/VCI value with ingress interface information, CSR determines the egress interface and egress VPI/VCI value.
In order to configure the cut-through packet forwarding state, a pair of neighbor nodes have to share the mapping information between the packet flow and the datalink VC. FANP (Flow Attribute Notification Protocol) described in this memo is the protocol to configure and manage the cut-through packet forwarding state.
2. Protocol Requirements and Future Enhancement
2.1 Protocol Requirements
The followings are the protocol requirements for FANP.
(1) Applicable to various types of CO datalink platforms
(2) Available with various connection types (i.e., SVC, PVC, VP)
(3) Robust operation The system should operate correctly even under the followin...