2-4 Riverstone Networks RS 3000/3100/3200 Switch Router Getting Started Guide
Software Overview Introduction
2.3 SOFTWARE OVERVIEW
This section describes the features and capabilities of the RS 3000, RS 3100 and RS 3200 in greater detail. For full
information regarding the use of these features and capabilities, see the Riverstone RS Switch Router User Guide.
2.3.1 Bridging
The RS 3000, RS 3100 and RS 3200 provide the following types of wire-speed bridging:
Address-based bridging – The RS 3000, RS 3100 and RS 3200 perform 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 RS Switch Router’s own MAC
address, the packet is routed rather than bridged.
Flow-based bridging – The RS 3000, RS 3100 and RS 3200 perform 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 Switch Router’s 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 3000, RS 3100 and RS 3200 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 3000, RS 3100 and RS 3200 support 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 3000,
RS 3100 and RS 3200 confine MAC-layer broadcasts to the ports in the VLAN on which the broadcast originates.
RS 3000 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 3000 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 3000, RS 3100 and RS 3200 support 802.1Q trunk ports, which allow you to use a single port to “trunk” traffic
from multiple VLANs to another RS 3000, RS 3100 or RS 3200 or to a switch that supports 802.1Q.
2.3.3 Routing
The RS 3000, RS 3100 and RS 3200 provide 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