Policy-Based Routing; Unidirectional Link Routing; Vrf-Lite; Qos Features - Cisco 4500M Software Manual

QoS Features

Policy-Based Routing

Traditional IP forwarding decisions are based purely on the destination IP address of the packet being
forwarded. Policy Based Routing (PBR) enables forwarding based upon other information associated
with a packet, such as the source interface, IP source address, Layer 4 ports, and so on. This feature
allows network managers more flexibility in how they configure and design their networks.
For more information on policy-based routing, see

Unidirectional Link Routing

Unidirectional link routing (UDLR) provides a way to forward multicast packets over a physical
unidirectional interface (such as a satellite link of high bandwidth) to stub networks that have a back
channel.
For information on configuring unidirectional link routing, refer to the chapter "Configuring
Unidirectional Link Routing" in the Cisco IP and IP Routing Configuration Guide.

VRF-lite

VPN routing and forwarding (VRF-lite) is an extension of IP routing that provides multiple routing instances.
Along with BGP, it enables the creation of a Layer 3 VPN service by keeping separate IP routing and
forwarding tables for each VPN customer. VRF-lite uses input interfaces to distinguish routes for different
VPNs. It forms virtual packet-forwarding tables by associating one or more Layer 3 interfaces with each VRF,
allowing the creation of multiple Layer 3 VPNs on a single switch. Interfaces in a VRF could be either
physical, such as an Ethernet port, or logical, such as a VLAN switch virtual interface (SVI). However,
interfaces cannot belong to more than one VRF at any time.
For information on VRF-lite, see
QoS Features
The quality of service (QoS) features prevent congestion by selecting network traffic and prioritizing it
according to its relative importance. Implementing QoS in your network makes network performance
more predictable and bandwidth use more effective.
The Catalyst 4500 series switch supports the following QoS features:
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Catalyst 4500 series switch supports trusted boundary, which uses the Cisco Discovery Protocol (CDP)
to detect the presence of a Cisco IP phone (such as the Cisco IP Phone 7910, 7935, 7940, and 7960) on
a switch port. If the telephone is not detected, the trusted boundary feature disables the trusted setting
on the switch port and prevents misuse of a high-priority queue.
The Catalyst 4500 series switch also supports QoS Automation (Auto QoS), which simplifies the
deployment of existing QoS features through automatic configuration.
For information on QoS and Auto QoS, see
Software Configuration Guide—Release 12.2(25)EW
1-10
Classification and marking
Ingress and egress policing
Sharing and shaping
Chapter 26, "Configuring Policy-Based Routing."
Chapter 28, "Configuring VRF-lite."
Chapter 29, "Configuring QoS."
Chapter 1 Product Overview
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