Self Configuring Routing and 802.1D Bridging Bridge with automatic hierarchical local MAC addresses

Profil Titel	Self Configuring Routing and 802.1D Bridging Bridge with automatic hierarchical local MAC addresses
Referenz	09 ES 28F8 3G0Y
Herkunftsland	Spain
Kooperationsart	Angebot
Eintrag/Änderung	2010-03-03 / 2011-01-18
Status	Dieses Profil ist abgelaufen! Falls Sie denoch Interesse haben, kontaktieren Sie uns. (2012-01-18)

Kurzfassung

A Spanish research center offers the first hierarchical routing protocol on layer two using self configured standard local MAC addresses. Makes Ethernet networks scalable without encapsulation. Compatible and self configurable within IEEE 802.1D standard bridges through a combined spanning tree protocol. Simple application of Up/Down routing and Distance Vector principles, enhanced Turn Prohibition mechanisms that allow last turn to destination branch to be permitted.License agreement is sought.

Details

CHT (Combined Hierarchical Tree) protocol is a datalink level network protocol that can be considered of as composed by two partial protocols: CSTP and HURP.
CSTP is a spanning tree protocol tree which builds up a central spanning tree exclusively formed by the combined capacity bridges with connectivity among them. The Standard 802.1D bridges, , get connected to it automatically, grouped in standard spanning subtrees.

HURP (Hierarchical Up/down Routing) Protocol broadcasts the routes to neighbouring network bridges (those directly connected by a link) and routes the frames destined to the hierarchically assigned local MAC addresses complementing the standard (802.1D) routing through different schemes: with vertical and cross routing and with Turn Prohibition mechanisms.

HLMAC addressing and vertical routing through tree:
HURP protocol allows direct routing through expansion tree links with no use of tables, frame broadcasting or address learning on the ports, by means of direct switching by decoding the frame’s hierarchical HLMAC destination address. The frame rises up to the bridge whose prefix address is on the destination HLMAC address, and then goes down by the branch to the destination host. (Figure 2. Block diagram of HLMAC addressing and HURP (vertical) routing through tree)

Transversal HURP Routing:
HURP routing allows selecting transversal routes, alternative to the spanning tree. The use of distance vectors allows bridges to calculate optimal routes and assess whether they will go through the tree or transversal links. Figure 3 shows the route, represented by a discontinuous arrow, that follows a frame starting from a origin end equipment (O”), whose hierarchical local MAC address is 32.7.6.5.1, until arriving to a destination end equipment (F”), with hierarchical local MAC address 32.7.1.5.0.0. The first leaf bridge (H1) acknowledges an intermediate bridge (BR3) which allows for a faster route by routing the frame through the (A2) transversal link between bridges H1 and BR3, and then continuing through the A3 transversal link connecting said (BR3) intermediate bridge until reaching BR2 bridge that is connected to the (F”) destination end equipment.

Combined spanning tree. CSTP protocol: a spanning tree protocol that builds up a central spanning tree exclusively formed by the combined capacity bridges with connectivity among them and to whom the standard bridges, grouped in spanning subtrees, are connected. The figure below shows a mixed network composed by 802.1D standard and combined bridges. Standard bridges are connected in subtrees to the main tree composed by the interconnected combined bridges (Figure 3)

Turn Prohibition: HURP protocol employs turn prohibition mechanisms to avoid user frame loops due to the transitory inconsistency of routing tables. These mechanisms also prevent the deadlocks that may occur due to de cyclic dependence of the paths of the devices.

The standard spanning tree protocol, STP or RSTP, ensures by itself the absence of loops during its convergence by blocking the network bridge ports that may originate a loop, including all designated ports that block and those that get blocked following the protocol.

The HLMAC hierarchical coordinates allow applying the Up/Down conventional turn prohibition (Autonet, Smartbridge), and those enhanced using additional information included on the HLMAC addresses.

Innovative Aspects:
Technology based on a RSTP generated hierarchical address tree which assigns each bridge a hierarchical address with topological meaning and that is employed for simple routing.

Includes a procedure for building up a hierarchical spanning tree from a root bridge with at least a bridge branching from it through a designated port and to whom a local MAC address expressing the bridge’s position on the spanning tree is automatically assigned.

The frames with local destination address (HLMAC) are routed through a procedure using the hierarchical spanning tree with no address learning, and an innovative routing through transversal links (which are disabled by STP protocol) if the route cost is less or equal or when the use of the installed network wants to be improved.

All the (combined) extended bridges that have been assigned a hierarchical local MAC address can also process frames with universal MAC addresses assigned to destination terminals, such as an 802.1D standard bridge.

This hierarchical tree is build up together with the 802.1D standard bridge resulting in a combined spanning tree that comprises both expanded bridges and the 25 conventional bridges operating under 802.1D.

Standard 802.1D bridges can be turned into extended bridges by adding this functionality through a simple software migration.