Figure 1-5 Frame Relay To Atm Service Interworking; Tiered Networks; Routing Hubs And Interface Shelves - Cisco BPX-BXM-155-8DX Installation And Configuration Manual

Chapter 1 The BPX Switch: Functional Overview
Figure 1-5
Frame
Relay

Tiered Networks

Networks may be configured as:
•
•
By allowing CPE connections to connect to a non-routing node (interface shelf), a tiered network is able
to grow in size beyond that which would be possible with only routing nodes comprising the network.
Starting with Release 8.5, tiered networks support both BPX switch routing hubs and IGX switch
routing hubs. Voice and data connections originating and terminating on IGX switch interface shelves
(feeders) are routed across the routing network via their associated IGX switch routing hubs.
Tiered networks support multiservice connections, including Frame Relay, circuit data, voice, and
ATM. By allowing customer premiswe equipment to connect to a non-routing node (interface shelf), a
tiered network is able to grow in size beyond that which would be possible with only routing nodes.
Intermediate routing nodes must be IGX switches. IGX switch interface shelves are the only interface
shelves that can be connected to an IGX switch routing hub. With this addition, a tiered network
provides a multiservice capability (Frame Relay, circuit data, voice, and ATM).

Routing Hubs and Interface Shelves

In a tiered network, interface shelves at the access layer (edge) of the network are connected to routing
nodes via feeder trunks (Figure 1-6).
•
•
The routing hubs route the interface shelf connections across the core layer of the network.The interface
shelves do not need to maintain network topology nor connection routing information. This task is left
to their routing hubs.
This architecture provides an expanded network consisting of a number of non-routing nodes (interface
shelves) at the edge of the network that are connected to the network by their routing hubs.
Release 9.3.0, Part Number 78-10674-01 Rev. D0, July 2001
Frame Relay to ATM Service Interworking
Frame
Service
Relay
CPE interworking
function
Flat
All nodes perform routing and communicate fully with one another), or
Tiered
Interface shelves are connected to routing hubs, where the interface shelves are configured as
non-routing nodes.
Routing hubs
Those routing nodes with attached interface shelves are referred to as routing hubs.
Interface shelves
The interface shelves, sometimes referred to as feeders, are non-routing nodes.
CPE using a
standard, non-
ATM
ATM network service specific
convergence
Cisco BPX 8600 Series Installation and Configuration
BPX Switch Operation
protocol
1-13