Furquan Ansari

IP switching over fast ATM cell transport (IPSOFACTO): switching multicast flows

This paper describes a method for mapping IP flows to ATM switches. No signaling is necessary to setup a path through ATM switches. Switch controllers run a IP routing protocol and execute IP forwarding. The IPSOFACTO component is responsible for mapping a IP flow to a switched path. The focus of this paper is primarily on switching IP multicast flows.

IP multicast support in MPLS

Multicast support in an MPLS (multiprotocol label switching) network has yet to be defined. An MPLS network consists of label switching devices such as ATM. This document discusses both dense-mode and sparse-mode IP multicast within the context of an MPLS network. Unlike unicast routing, dense-mode multicast routing trees are established in a data-driven manner and it is not possible to topologically aggregate such trees, which are rooted at different sources. In sparse-mode multicast, source-specific trees may coexist with a core/shared tree, and it is not possible to assign a common label to traffic from different sources on a branch of the shared tree. This leads us to suggest a per-source traffic-driven label allocation scheme for supporting all three types of multicast (dense mode, shared tree, source tree) routing trees in an MPLS network.

Framework for IP switching over fast ATM cell transport (IPSOFACTO)

This paper describes a method for mapping IP flows to ATM switches. No signaling is necessary to setup a path through ATM switches. Switch controllers run an IP routing protocol and execute IP forwarding. The IPSOFACTO component is responsible for mapping a IP flow to a switched path. Mechanisms for switching both multicast and unicast flows are described.

IP switching over fast ATM cell transport (IPSOFACTO): IP multicast over wireless ATM

IPSOFACTO is an IP switching technique that directly maps IP flows to ATM VCs without any signalling. This paper extends IP multicast using IPSOFACTO over wireless ATM. A wireless ATM system consists of a fixed core network and a shared wireless access link for mobile terminals. Unlike point-to-point ATM links within the fixed/wired network, wireless ATM link uses a common VC space for all mobile terminals and the medium access (MAC) protocol supports shared multiple access on the downlink, but only point-to-point unicast access on the uplink. This paper describes how IP multicast can be natively supported on such WATM links using IPSOFACTO along with specific extensions to the Internet Group Management Protocol (IGMP). In addition, a cell-level error recovery scheme at the DLC (data link control) layer is described to enhance the packet-level throughput of the transport layer.

A framework for handling route changes and aggregation in IPSOFACTO

IPSOFACTO (IP Switching Over Fast ATM Cell Transport) is an IP switching technique that directly maps IP flows to ATM VCs without any signalling. A switched path for a new flow is setup while routing the first packet through the network. Subsequent packets are forwarded entirely at the cell-level through the switched path, and no further packet-level routing decision is taken at the intermediate nodes. This paper considers how changes in the network topology, as expressed through IP routing tables, can be correctly reflected back into the cell switched path associated with a flow. A simple scheme based on IP source routing and IP-in-IP encapsulation is proposed, which ensures that the impact of route changes is handled in a consistent manner exclusively by the ingress routers of an IPSOFACTO cloud. This scheme is further used by interior routers to identify point-to-point flows that can be aggregated and merged into a multipoint-to-point switched path, thus reducing the VC usage within an IPSOFACTO network. This scheme also allows switched paths with different classes-of-service to be setup within the cloud, when used in conjunction with RSVP. It relies on the underlying routing protocol to either provide a complete topology of the network (e.g. OSPF) or a complete path between every ingress-egress pair (e.g. BGP).

Dynamic QoS for IP switching using RSVP over IPSOFACTO

This paper explores how dynamic quality-of-service may be supported through RSVP over IPSOFACTO within a network of ATM switches. IPSOFACTO is a methodology fur supporting IP directly over ATM switches. Application endpoints communicate exclusively via IP and no ATM signalling is involved. The applications dynamic QoS requirements are communicated by a user through a novel user interface, called CockpitView, and these are signalled through the network via RSVP running directly on ATM switches. Models to accommodate receiver heterogeneity in this environment are described. A Traffic Control module interfacing to both RSVP signalling and IPSOFACTO is presented. Finally, an experimental setup over the MAY/BALI networks integrating IPSOFACTO, RSVP and CockpitView is presented.