Cisco Systems 8600 Series manual Definitions, Co-locating Routing Hubs and Shelves

IGX Routing Hubs in a Tiered Network

Definitions

IGX Routing Hub	An IGX node in the routing network which has attached IGX
	interface shelves. Also referred to as a hub node or IGX hub.
IGX Interface Shelf	A special configuration of an IGX switch that is connected as a shelf
	to an IGX routing hub. An IGX interface shelf is sometimes referred
	to as IGX A/F or feeder. The IGX interface shelf does not perform
	routing functions nor keep track of network topology.
Feeder Trunk	Refers to a trunk which interconnects an IGX interface shelf with
	the routing network via an IGX routing hub. A feeder trunk is
	sometimes referred to as an interface shelf trunk.
IGX/AF	Another name for the IGX interface shelf
Routing Network	The portion of the tiered network which performs automatic routing
	between connection endpoints.
VPI	Virtual Path Identifier
VCI	Virtual Connection Identifier

Upgrades

Converting an IGX node to an interface shelf requires re-configuring connections on the node, as no upgrade path is provided in changing a routing node to an interface shelf.

Only IGX nodes are able to act hub nodes for IGX interface shelves for voice and data transport over the IGX tiered network. An IGX node, acting as a hub node, is not restricted from providing any other feature which is normally available on IGX nodes. An IGX hub supports up to 4 IGX interface shelves.

Connections within tiered networks consist of three distinct segments within each tier. A routing segment traverses the routing network, with an interface shelf segment at each end providing connectivity to the interface shelf end-point. Each of these segments are added, configured and deleted independently of the other segments. The Cisco StrataView Plus Connection Manager provides management of these individual segments as a single end-to-end connection.

Interface shelves are attached to the routing network via an IGX node using a BTM E1 trunk. The connection segments within the routing network are terminated on IGX feeder trunks.

Co-locating Routing Hubs and Shelves

The feeder trunk between an interface shelf and the routing network is a single point of failure, therefore, the interface shelves should be co-located with their associated hub node. Card level redundancy is supported by the Y-Cable redundancy for the CVM, LDM, and HDM.

Network Management

Communication between CPE devices and the routing network is provided in accordance with Annex G of Recommendation Q.2931. This is a bidirectional protocol for monitoring the status of connections across a UNI interface.

13-12Cisco BPX 8600 Series Reference