Cisco Systems 3750E manual Large Network Using Catalyst 3750-E and 3560-E Switches

Chapter 1 Overview

Network Configuration Examples

Large Network Using Catalyst 3750-E and 3560-E Switches

Switches in the wiring closet have traditionally been only Layer 2 devices, but as network traffic profiles evolve, switches in the wiring closet are increasingly employing multilayer services such as multicast management and traffic classification. Figure 1-9shows a configuration for a network that uses only Catalyst 3750-E multilayer switch stacks in the wiring closets and two backbone switches, such as the Catalyst 6500 switches, to aggregate up to ten wiring closets. Figure 1-10shows a configuration for a network that uses only Catalyst 3560-E multilayer switches in the wiring closets and two backbone switches, such as the Catalyst 6500 switches, to aggregate up to ten wiring closets.

In the wiring closet, each switch stack or switch has IGMP snooping enabled to efficiently forward multimedia and multicast traffic. QoS ACLs that either drop or mark nonconforming traffic based on bandwidth limits are also configured on each switch stack or switch. VLAN maps provide intra-VLAN security and prevent unauthorized users from accessing critical pieces of the network. QoS features can limit bandwidth on a per-port or per-user basis. The switch ports are configured as either trusted or untrusted. You can configure a trusted port to trust the CoS value, the DSCP value, or the IP precedence. If you configure the port as untrusted, you can use an ACL to mark the frame in accordance with the network policy.

Each switch stack or switch provides inter-VLAN routing. They provide proxy ARP services to get IP and MAC address mapping, thereby removing this task from the routers and decreasing this type of traffic on the WAN links. These switch stacks or switches also have redundant uplink connections to the backbone switches, with each uplink port configured as a trusted routed uplink to provide faster convergence in case of an uplink failure.

The routers and backbone switches have HSRP enabled for load-balancing and redundant connectivity to guarantee mission-critical traffic.

Catalyst 3750-E and 3560-E Switch Software Configuration Guide

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