2-4 Riverstone Networks RS 8000/8600 Switch Router Getting Started Guide
Software Overview
Introduction
2.3
SOFTWARE OVERVIEW
This section describes the features and capabilities of the RS 8000/8600 in greater detail.
2.3.1
Bridging
The RS provides the following types of wire-speed bridging:
Address-based bridging
– The RS performs this type of bridging by looking up a packet’s destination address in an
L2 lookup table on the line card that received the packet from the network. The L2 lookup table indicates the exit
port(s) for the bridged packet. If the packet is addressed to the router’s own MAC address, the packet is routed rather
than bridged.
Flow-based bridging
– The RS performs this type of bridging by looking up a packet’s source and destination address
in an L2 lookup table on the line card that received the packet from the network.
Your choice of bridging method does not affect RS performance. However, address-based bridging requires fewer table
entries. Alternately, while flow-based bridging uses more table entries, it provides tighter management and control
over bridged traffic, and greater resolution to RMON I statistics.
The RS ports perform address-based bridging by default, but can be configured to perform flow-based bridging on a
per-port basis. A port cannot be configured to perform both types of bridging at the same time.
2.3.2
Port and Protocol VLANs
The RS supports the following types of Virtual LANs (VLANs):
Port-based VLANs
– A port-based VLAN is a set of ports that comprises a layer-2 broadcast domain. The RS confines
MAC-layer broadcasts to the ports in the VLAN on which the broadcast originates. RS ports outside the VLAN do not
receive the broadcast.
Protocol-based VLANs
– A protocol-based VLAN is a named set of ports that comprises an IP, IPX, AppleTalk,
DECNet, SNA, IPv6, or L2 broadcast domain. The RS confines protocol-specific broadcasts to the ports within the
protocol-based VLAN. Protocol-based VLANs sometimes are called subnet VLANs or layer-3 VLANs.
You can include the same port in more than one VLAN, even in both port-based and protocol-based VLANs.
Moreover, you can define VLANs that span across multiple RS switch routers. To simplify VLAN administration, the
RS supports 802.1Q trunk ports, which allow you to use a single port to “trunk” traffic from multiple VLANs to
another RS or to a switch that supports 802.1Q.
2.3.3
Routing
The RS provides wire-speed routing for the following protocols:
IP
– protocol that switching and routing devices use for moving traffic within the Internet and within many corporate
intranets
IPX
– protocol by Novell used in NetWare products
